diff --git a/CHANGES b/CHANGES
index bbee3c57d37..4cef97c8a8e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -19,6 +19,14 @@ $ pipx install --suffix=@next 'tmuxp' --pip-args '\--pre' --force
 
 <!-- Maintainers, insert changes / features for the next release here -->
 
+### Development
+
+- Code quality improved via [ruff] rules (#879)
+
+  This includes fixes made by hand alongside ruff's automated fixes. The more
+  stringent rules include import sorting, and still runs almost instantly
+  against the whole codebase.
+
 ## tmuxp 1.29.1 (2023-09-02)
 
 ### Development
diff --git a/conftest.py b/conftest.py
index 5ee456980de..024ccbf9d96 100644
--- a/conftest.py
+++ b/conftest.py
@@ -10,10 +10,9 @@
 import typing as t
 
 import pytest
-
 from _pytest.doctest import DoctestItem
-
 from libtmux.test import namer
+
 from tests.fixtures import utils as test_utils
 from tmuxp.workspace.finders import get_workspace_dir
 
@@ -24,7 +23,7 @@
 USING_ZSH = "zsh" in os.getenv("SHELL", "")
 
 
-@pytest.mark.skipif(USING_ZSH, reason="Using ZSH")
+@pytest.mark.skipif(not USING_ZSH, reason="Using ZSH")
 @pytest.fixture(autouse=USING_ZSH, scope="session")
 def zshrc(user_path: pathlib.Path) -> pathlib.Path:
     """This quiets ZSH default message.
@@ -70,7 +69,7 @@ def monkeypatch_plugin_test_packages(monkeypatch: pytest.MonkeyPatch) -> None:
         "tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/",
     ]
     for path in paths:
-        monkeypatch.syspath_prepend(os.path.abspath(os.path.relpath(path)))
+        monkeypatch.syspath_prepend(str(pathlib.Path(path).resolve()))
 
 
 @pytest.fixture(scope="function")
diff --git a/docs/_ext/aafig.py b/docs/_ext/aafig.py
index 2c5775043c0..3770613d68e 100644
--- a/docs/_ext/aafig.py
+++ b/docs/_ext/aafig.py
@@ -12,6 +12,7 @@
 """
 import logging
 import posixpath
+import typing as t
 from hashlib import sha1 as sha
 from os import path
 
@@ -28,11 +29,11 @@
 
 logger = logging.getLogger(__name__)
 
-DEFAULT_FORMATS = dict(html="svg", latex="pdf", text=None)
+DEFAULT_FORMATS = {"html": "svg", "latex": "pdf", "text": None}
 
 
 def merge_dict(dst, src):
-    for (k, v) in src.items():
+    for k, v in src.items():
         if k not in dst:
             dst[k] = v
     return dst
@@ -58,22 +59,22 @@ class AafigDirective(images.Image):
 
     has_content = True
     required_arguments = 0
-    own_option_spec = dict(
-        line_width=float,
-        background=str,
-        foreground=str,
-        fill=str,
-        aspect=nonnegative_int,
-        textual=flag,
-        proportional=flag,
-    )
+    own_option_spec: t.ClassVar = {
+        "line_width": float,
+        "background": str,
+        "foreground": str,
+        "fill": str,
+        "aspect": nonnegative_int,
+        "textual": flag,
+        "proportional": flag,
+    }
     option_spec = images.Image.option_spec.copy()
     option_spec.update(own_option_spec)
 
     def run(self):
-        aafig_options = dict()
-        own_options_keys = [self.own_option_spec.keys()] + ["scale"]
-        for (k, v) in self.options.items():
+        aafig_options = {}
+        own_options_keys = [self.own_option_spec.keys(), "scale"]
+        for k, v in self.options.items():
             if k in own_options_keys:
                 # convert flags to booleans
                 if v is None:
@@ -88,7 +89,7 @@ def run(self):
         if isinstance(image_node, nodes.system_message):
             return [image_node]
         text = "\n".join(self.content)
-        image_node.aafig = dict(options=aafig_options, text=text)
+        image_node.aafig = {"options": aafig_options, "text": text}
         return [image_node]
 
 
@@ -138,13 +139,18 @@ def render_aafig_images(app, doctree):
                 img["height"] = height
 
 
+class AafigureNotInstalled(AafigError):
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        return super().__init__("aafigure module not installed", *args, **kwargs)
+
+
 def render_aafigure(app, text, options):
     """
     Render an ASCII art figure into the requested format output file.
     """
 
     if aafigure is None:
-        raise AafigError("aafigure module not installed")
+        raise AafigureNotInstalled()
 
     fname = get_basename(text, options)
     fname = "{}.{}".format(get_basename(text, options), options["format"])
@@ -173,10 +179,10 @@ def render_aafigure(app, text, options):
                 f = None
                 try:
                     try:
-                        f = open(metadata_fname)
-                        extra = f.read()
-                    except Exception:
-                        raise AafigError()
+                        with open(metadata_fname) as f:
+                            extra = f.read()
+                    except Exception as e:
+                        raise AafigError() from e
                 finally:
                     if f is not None:
                         f.close()
@@ -190,14 +196,13 @@ def render_aafigure(app, text, options):
         (visitor, output) = aafigure.render(text, outfn, options)
         output.close()
     except aafigure.UnsupportedFormatError as e:
-        raise AafigError(str(e))
+        raise AafigError(str(e)) from e
 
     extra = None
     if options["format"].lower() == "svg":
         extra = visitor.get_size_attrs()
-        f = open(metadata_fname, "w")
-        f.write(extra)
-        f.close()
+        with open(metadata_fname, "w") as f:
+            f.write(extra)
 
     return relfn, outfn, id, extra
 
@@ -206,7 +211,7 @@ def setup(app):
     app.add_directive("aafig", AafigDirective)
     app.connect("doctree-read", render_aafig_images)
     app.add_config_value("aafig_format", DEFAULT_FORMATS, "html")
-    app.add_config_value("aafig_default_options", dict(), "html")
+    app.add_config_value("aafig_default_options", {}, "html")
 
 
 # vim: set expandtab shiftwidth=4 softtabstop=4 :
diff --git a/docs/conf.py b/docs/conf.py
index 5bf2406606b..fea1c2e785f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,10 +1,10 @@
 # flake8: NOQA: E501
 import contextlib
 import inspect
+import pathlib
 import sys
 import typing as t
 from os.path import relpath
-import pathlib
 
 import tmuxp
 
@@ -172,12 +172,12 @@
 }
 
 # aafig format, try to get working with pdf
-aafig_format = dict(latex="pdf", html="gif")
+aafig_format = {"latex": "pdf", "html": "gif"}
 
-aafig_default_options = dict(scale=0.75, aspect=0.5, proportional=True)
+aafig_default_options = {"scale": 0.75, "aspect": 0.5, "proportional": True}
 
 
-def linkcode_resolve(domain, info):  # NOQA: C901
+def linkcode_resolve(domain, info):
     """
     Determine the URL corresponding to Python object
 
@@ -200,7 +200,7 @@ def linkcode_resolve(domain, info):  # NOQA: C901
     for part in fullname.split("."):
         try:
             obj = getattr(obj, part)
-        except Exception:
+        except Exception:  # NOQA: PERF203
             return None
 
     # strip decorators, which would resolve to the source of the decorator
@@ -224,10 +224,7 @@ def linkcode_resolve(domain, info):  # NOQA: C901
     except Exception:
         lineno = None
 
-    if lineno:
-        linespec = "#L%d-L%d" % (lineno, lineno + len(source) - 1)
-    else:
-        linespec = ""
+    linespec = "#L%d-L%d" % (lineno, lineno + len(source) - 1) if lineno else ""
 
     fn = relpath(fn, start=pathlib.Path(tmuxp.__file__).parent)
 
diff --git a/pyproject.toml b/pyproject.toml
index 85e938d9dd8..e90bba676ae 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -155,6 +155,35 @@ module = [
 ]
 ignore_missing_imports = true
 
+[tool.ruff]
+target-version = "py37"
+select = [
+  "E", # pycodestyle
+  "F", # pyflakes
+  "I", # isort
+  "UP",  # pyupgrade
+  "B", # flake8-bugbear
+  "C4", # flake8-comprehensions
+  "Q", # flake8-quotes
+  "PTH", # flake8-use-pathlib
+  "SIM",  # flake8-simplify
+  "TRY", # Trycertatops
+  "PERF", # Perflint
+  "RUF" # Ruff-specific rules
+]
+
+[tool.ruff.isort]
+known-first-party = [
+  "tmuxp"
+]
+combine-as-imports = true
+
+[tool.ruff.per-file-ignores]
+"*/__init__.py" = ["F401"]
+"src/tmuxp/workspace/finders.py" = ["PTH"]
+"src/tmuxp/cli/*.py" = ["PTH"]
+"docs/_ext/aafig.py" = ["PTH"]
+
 [build-system]
 requires = ["poetry_core>=1.0.0"]
 build-backend = "poetry.core.masonry.api"
diff --git a/src/tmuxp/cli/convert.py b/src/tmuxp/cli/convert.py
index d10e5bd4359..96251cec721 100644
--- a/src/tmuxp/cli/convert.py
+++ b/src/tmuxp/cli/convert.py
@@ -6,6 +6,7 @@
 from tmuxp.config_reader import ConfigReader
 from tmuxp.workspace.finders import find_workspace_file, get_workspace_dir
 
+from .. import exc
 from .utils import prompt_yes_no
 
 if t.TYPE_CHECKING:
@@ -40,6 +41,13 @@ def create_convert_subparser(
     return parser
 
 
+class ConvertUnknownFileType(exc.TmuxpException):
+    def __init__(self, ext: str, *args: object, **kwargs: object) -> None:
+        return super().__init__(
+            f"Unknown filetype: {ext} (valid: [.json, .yaml, .yml])"
+        )
+
+
 def command_convert(
     workspace_file: t.Union[str, pathlib.Path],
     answer_yes: bool,
@@ -61,7 +69,7 @@ def command_convert(
     elif ext in [".yaml", ".yml"]:
         to_filetype = "json"
     else:
-        raise Exception(f"Unknown filetype: {ext} (valid: [.json, .yaml, .yml])")
+        raise ConvertUnknownFileType(ext)
 
     configparser = ConfigReader.from_file(workspace_file)
     newfile = workspace_file.parent / (str(workspace_file.stem) + f".{to_filetype}")
@@ -72,13 +80,14 @@ def command_convert(
         **{"default_flow_style": False} if to_filetype == "yaml" else {},
     )
 
-    if not answer_yes:
-        if prompt_yes_no(f"Convert to <{workspace_file}> to {to_filetype}?"):
-            if prompt_yes_no("Save workspace to %s?" % newfile):
-                answer_yes = True
+    if (
+        not answer_yes
+        and prompt_yes_no(f"Convert to <{workspace_file}> to {to_filetype}?")
+        and prompt_yes_no("Save workspace to %s?" % newfile)
+    ):
+        answer_yes = True
 
     if answer_yes:
-        buf = open(newfile, "w")
-        buf.write(new_workspace)
-        buf.close()
+        with open(newfile, "w") as buf:
+            buf.write(new_workspace)
         print(f"New workspace file saved to <{newfile}>.")
diff --git a/src/tmuxp/cli/debug_info.py b/src/tmuxp/cli/debug_info.py
index a23fac1f88f..d72e3fc1ac6 100644
--- a/src/tmuxp/cli/debug_info.py
+++ b/src/tmuxp/cli/debug_info.py
@@ -7,7 +7,6 @@
 import typing as t
 
 from colorama import Fore
-
 from libtmux.__about__ import __version__ as libtmux_version
 from libtmux.common import get_version, tmux_cmd
 
@@ -34,7 +33,7 @@ def prepend_tab(strings):
         """
         Prepend tab to strings in list.
         """
-        return list(map(lambda x: "\t%s" % x, strings))
+        return ["\t%s" % x for x in strings]
 
     def output_break():
         """
diff --git a/src/tmuxp/cli/freeze.py b/src/tmuxp/cli/freeze.py
index 2383a435ba5..0f22257fc18 100644
--- a/src/tmuxp/cli/freeze.py
+++ b/src/tmuxp/cli/freeze.py
@@ -5,11 +5,12 @@
 import typing as t
 
 from libtmux.server import Server
+
 from tmuxp.config_reader import ConfigReader
 from tmuxp.exc import TmuxpException
 from tmuxp.workspace.finders import get_workspace_dir
 
-from .. import util
+from .. import exc, util
 from ..workspace import freezer
 from .utils import prompt, prompt_choices, prompt_yes_no
 
@@ -105,7 +106,7 @@ def command_freeze(
             session = util.get_session(server)
 
         if not session:
-            raise TmuxpException("Session not found.")
+            raise exc.SessionNotFound()
     except TmuxpException as e:
         print(e)
         return
@@ -194,9 +195,8 @@ def extract_workspace_format(
         destdir = os.path.dirname(dest)
         if not os.path.isdir(destdir):
             os.makedirs(destdir)
-        buf = open(dest, "w")
-        buf.write(workspace)
-        buf.close()
+        with open(dest, "w") as buf:
+            buf.write(workspace)
 
         if not args.quiet:
             print("Saved to %s." % dest)
diff --git a/src/tmuxp/cli/import_config.py b/src/tmuxp/cli/import_config.py
index 895ee6f2141..301f0dd8cfb 100644
--- a/src/tmuxp/cli/import_config.py
+++ b/src/tmuxp/cli/import_config.py
@@ -11,7 +11,7 @@
 from .utils import prompt, prompt_choices, prompt_yes_no, tmuxp_echo
 
 
-def get_tmuxinator_dir() -> str:
+def get_tmuxinator_dir() -> pathlib.Path:
     """
     Return tmuxinator configuration directory.
 
@@ -19,7 +19,7 @@ def get_tmuxinator_dir() -> str:
 
     Returns
     -------
-    str :
+    pathlib.Path :
         absolute path to tmuxinator config directory
 
     See Also
@@ -27,25 +27,25 @@ def get_tmuxinator_dir() -> str:
     :meth:`tmuxp.workspace.importers.tmuxinator.import_tmuxinator`
     """
     if "TMUXINATOR_CONFIG" in os.environ:
-        return os.path.expanduser(os.environ["TMUXINATOR_CONFIG"])
+        return pathlib.Path(os.environ["TMUXINATOR_CONFIG"]).expanduser()
 
-    return os.path.expanduser("~/.tmuxinator/")
+    return pathlib.Path("~/.tmuxinator/").expanduser()
 
 
-def get_teamocil_dir() -> str:
+def get_teamocil_dir() -> pathlib.Path:
     """
     Return teamocil configuration directory.
 
     Returns
     -------
-    str :
+    pathlib.Path :
         absolute path to teamocil config directory
 
     See Also
     --------
     :meth:`tmuxp.workspace.importers.teamocil.import_teamocil`
     """
-    return os.path.expanduser("~/.teamocil/")
+    return pathlib.Path("~/.teamocil/").expanduser()
 
 
 def _resolve_path_no_overwrite(workspace_file: str) -> str:
@@ -153,9 +153,8 @@ def import_config(
             if prompt_yes_no("Save to %s?" % dest_path):
                 dest = dest_path
 
-        buf = open(dest, "w")
-        buf.write(new_config)
-        buf.close()
+        with open(dest, "w") as buf:
+            buf.write(new_config)
 
         tmuxp_echo("Saved to %s." % dest)
     else:
diff --git a/src/tmuxp/cli/load.py b/src/tmuxp/cli/load.py
index 46862bb4238..de21db1aa6a 100644
--- a/src/tmuxp/cli/load.py
+++ b/src/tmuxp/cli/load.py
@@ -16,6 +16,7 @@
 from libtmux.common import has_gte_version
 from libtmux.server import Server
 from libtmux.session import Session
+
 from tmuxp.types import StrPath
 
 from .. import config_reader, exc, log, util
@@ -90,11 +91,7 @@ def set_layout_hook(session: Session, hook_name: str) -> None:
         hook_cmd.append("selectw -p")
 
     # unset the hook immediately after executing
-    hook_cmd.append(
-        "set-hook -u -t {target_session} {hook_name}".format(
-            target_session=session.id, hook_name=hook_name
-        )
-    )
+    hook_cmd.append(f"set-hook -u -t {session.id} {hook_name}")
     hook_cmd.append(f"selectw -t {attached_window.id}")
 
     # join the hook's commands with semicolons
@@ -118,12 +115,26 @@ def load_plugins(session_config: t.Dict[str, t.Any]) -> t.List[t.Any]:
                 module_name = plugin.split(".")
                 module_name = ".".join(module_name[:-1])
                 plugin_name = plugin.split(".")[-1]
+            except Exception as error:
+                tmuxp_echo(
+                    style("[Plugin Error] ", fg="red")
+                    + f"Couldn't load {plugin}\n"
+                    + style(f"{error}", fg="yellow")
+                )
+                sys.exit(1)
+
+            try:
                 plugin = getattr(importlib.import_module(module_name), plugin_name)
                 plugins.append(plugin())
             except exc.TmuxpPluginException as error:
                 if not prompt_yes_no(
-                    "%sSkip loading %s?"
-                    % (style(str(error), fg="yellow"), plugin_name),
+                    "{}Skip loading {}?".format(
+                        style(
+                            str(error),
+                            fg="yellow",
+                        ),
+                        plugin_name,
+                    ),
                     default=True,
                 ):
                     tmuxp_echo(
diff --git a/src/tmuxp/cli/shell.py b/src/tmuxp/cli/shell.py
index 7ea117cbf20..d0774b2dffa 100644
--- a/src/tmuxp/cli/shell.py
+++ b/src/tmuxp/cli/shell.py
@@ -166,7 +166,7 @@ def command_shell(
         session=session, window_name=args.window_name, current_pane=current_pane
     )
 
-    pane = util.get_pane(window=window, current_pane=current_pane)  # NOQA: F841
+    pane = util.get_pane(window=window, current_pane=current_pane)
 
     if args.command is not None:
         exec(args.command)
diff --git a/src/tmuxp/cli/utils.py b/src/tmuxp/cli/utils.py
index 9a2d41df9c4..91f2ef165c5 100644
--- a/src/tmuxp/cli/utils.py
+++ b/src/tmuxp/cli/utils.py
@@ -4,6 +4,12 @@
 
 from .. import log
 
+if t.TYPE_CHECKING:
+    from typing_extensions import TypeAlias
+
+    CLIColour: TypeAlias = t.Union[int, t.Tuple[int, int, int], str]
+
+
 logger = logging.getLogger(__name__)
 
 
@@ -126,7 +132,7 @@ def prompt_choices(
         if isinstance(choice, str):
             options.append(choice)
         elif isinstance(choice, tuple):
-            options.append("%s [%s]" % (choice, choice[0]))
+            options.append(f"{choice} [{choice[0]}]")
             choice = choice[0]
         _choices.append(choice)
 
@@ -183,10 +189,15 @@ def _interpret_color(
     return str(_ansi_colors[color] + offset)
 
 
+class UnknownStyleColor(Exception):
+    def __init__(self, color: "CLIColour", *args: object, **kwargs: object) -> None:
+        return super().__init__(f"Unknown color {color!r}", *args, **kwargs)
+
+
 def style(
     text: t.Any,
-    fg: t.Optional[t.Union[int, t.Tuple[int, int, int], str]] = None,
-    bg: t.Optional[t.Union[int, t.Tuple[int, int, int], str]] = None,
+    fg: t.Optional["CLIColour"] = None,
+    bg: t.Optional["CLIColour"] = None,
     bold: t.Optional[bool] = None,
     dim: t.Optional[bool] = None,
     underline: t.Optional[bool] = None,
@@ -207,13 +218,13 @@ def style(
         try:
             bits.append(f"\033[{_interpret_color(fg)}m")
         except KeyError:
-            raise TypeError(f"Unknown color {fg!r}") from None
+            raise UnknownStyleColor(color=fg) from None
 
     if bg:
         try:
             bits.append(f"\033[{_interpret_color(bg, 10)}m")
         except KeyError:
-            raise TypeError(f"Unknown color {bg!r}") from None
+            raise UnknownStyleColor(color=bg) from None
 
     if bold is not None:
         bits.append(f"\033[{1 if bold else 22}m")
diff --git a/src/tmuxp/config_reader.py b/src/tmuxp/config_reader.py
index 6f3683c6dbb..b3562da7d7a 100644
--- a/src/tmuxp/config_reader.py
+++ b/src/tmuxp/config_reader.py
@@ -99,7 +99,7 @@ def _from_file(cls, path: pathlib.Path) -> t.Dict[str, t.Any]:
         {'session_name': 'my session'}
         """
         assert isinstance(path, pathlib.Path)
-        content = open(path).read()
+        content = path.open().read()
 
         if path.suffix in [".yaml", ".yml"]:
             format: "FormatLiteral" = "yaml"
diff --git a/src/tmuxp/exc.py b/src/tmuxp/exc.py
index e8801e19f0c..5fb0d9f722f 100644
--- a/src/tmuxp/exc.py
+++ b/src/tmuxp/exc.py
@@ -6,6 +6,8 @@
 """
 import typing as t
 
+from libtmux._internal.query_list import ObjectDoesNotExist
+
 from ._compat import implements_to_string
 
 
@@ -19,10 +21,58 @@ class WorkspaceError(TmuxpException):
     """Error parsing tmuxp workspace data."""
 
 
+class SessionNotFound(TmuxpException):
+    def __init__(
+        self, session_target: t.Optional[str] = None, *args: object, **kwargs: object
+    ) -> None:
+        msg = "Session not found"
+        if session_target is not None:
+            msg += f": {session_target}"
+        return super().__init__(msg, *args, **kwargs)
+
+
+class WindowNotFound(TmuxpException):
+    def __init__(
+        self, window_target: t.Optional[str] = None, *args: object, **kwargs: object
+    ) -> None:
+        msg = "Window not found"
+        if window_target is not None:
+            msg += f": {window_target}"
+        return super().__init__(msg, *args, **kwargs)
+
+
+class PaneNotFound(TmuxpException):
+    def __init__(
+        self, pane_target: t.Optional[str] = None, *args: object, **kwargs: object
+    ) -> None:
+        msg = "Pane not found"
+        if pane_target is not None:
+            msg += f": {pane_target}"
+        return super().__init__(msg, *args, **kwargs)
+
+
 class EmptyWorkspaceException(WorkspaceError):
 
     """Workspace file is empty."""
 
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        return super().__init__("Session configuration is empty.", *args, **kwargs)
+
+
+class SessionMissingWorkspaceException(WorkspaceError, ObjectDoesNotExist):
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        return super().__init__(
+            "No session object exists for WorkspaceBuilder. "
+            "Tip: Add session_name in constructor or run WorkspaceBuilder.build()",
+            *args,
+            **kwargs,
+        )
+
+
+class ActiveSessionMissingWorkspaceException(WorkspaceError):
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        return super().__init__("No session active.", *args, **kwargs)
+
 
 class TmuxpPluginException(TmuxpException):
 
@@ -50,11 +100,11 @@ def __init__(
         self.cmd = cmd
         self.output = output
         self.message = (
-            "before_script failed with returncode {returncode}.\n"
-            "command: {cmd}\n"
+            f"before_script failed with returncode {self.returncode}.\n"
+            f"command: {self.cmd}\n"
             "Error output:\n"
-            "{output}"
-        ).format(returncode=self.returncode, cmd=self.cmd, output=self.output)
+            f"{self.output}"
+        )
 
     def __str__(self):
         return self.message
diff --git a/src/tmuxp/plugin.py b/src/tmuxp/plugin.py
index 8417d28f6c1..7d56316630c 100644
--- a/src/tmuxp/plugin.py
+++ b/src/tmuxp/plugin.py
@@ -139,14 +139,14 @@ def _version_check(self) -> None:
             assert isinstance(constraints, dict)
             try:
                 assert self._pass_version_check(**constraints)
-            except AssertionError:
+            except AssertionError as e:
                 raise TmuxpPluginException(
                     "Incompatible {dep} version: {version}\n{plugin_name} "
                     "requirements:\nmin: {vmin} | max: {vmax} | "
                     "incompatible: {incompatible}\n".format(
                         dep=dep, plugin_name=self.plugin_name, **constraints
                     )
-                )
+                ) from e
 
     def _pass_version_check(
         self,
diff --git a/src/tmuxp/shell.py b/src/tmuxp/shell.py
index 44aa6fe55e1..0f73721d6c3 100644
--- a/src/tmuxp/shell.py
+++ b/src/tmuxp/shell.py
@@ -6,6 +6,7 @@
 """
 import logging
 import os
+import pathlib
 import typing as t
 
 logger = logging.getLogger(__name__)
@@ -32,7 +33,7 @@ def has_ipython() -> bool:
 
 def has_ptpython() -> bool:
     try:
-        from ptpython.repl import embed, run_config  # NOQA F841
+        from ptpython.repl import embed, run_config  # F841
     except ImportError:
         try:
             from prompt_toolkit.contrib.repl import embed, run_config  # NOQA F841
@@ -44,8 +45,8 @@ def has_ptpython() -> bool:
 
 def has_ptipython() -> bool:
     try:
-        from ptpython.ipython import embed  # NOQA F841
-        from ptpython.repl import run_config  # NOQA F841
+        from ptpython.ipython import embed  # F841
+        from ptpython.repl import run_config  # F841
     except ImportError:
         try:
             from prompt_toolkit.contrib.ipython import embed  # NOQA F841
@@ -80,7 +81,7 @@ def get_bpython(options, extra_args=None):
     if extra_args is None:
         extra_args = {}
 
-    from bpython import embed  # NOQA F841
+    from bpython import embed  # F841
 
     def launch_bpython():
         imported_objects = get_launch_args(**options)
@@ -106,7 +107,7 @@ def launch_ipython():
             ipython_arguments = extra_args or get_ipython_arguments()
             start_ipython(argv=ipython_arguments, user_ns=imported_objects)
 
-        return launch_ipython
+        return launch_ipython  # NOQA: TRY300
     except ImportError:
         # IPython < 0.11
         # Explicitly pass an empty list as arguments, because otherwise
@@ -130,7 +131,7 @@ def get_ptpython(options, vi_mode=False):
 
     def launch_ptpython():
         imported_objects = get_launch_args(**options)
-        history_filename = os.path.expanduser("~/.ptpython_history")
+        history_filename = str(pathlib.Path("~/.ptpython_history").expanduser())
         embed(
             globals=imported_objects,
             history_filename=history_filename,
@@ -156,7 +157,7 @@ def get_ptipython(options, vi_mode=False):
 
     def launch_ptipython():
         imported_objects = get_launch_args(**options)
-        history_filename = os.path.expanduser("~/.ptpython_history")
+        history_filename = str(pathlib.Path("~/.ptpython_history").expanduser())
         embed(
             user_ns=imported_objects,
             history_filename=history_filename,
@@ -169,13 +170,17 @@ def launch_ptipython():
 
 def get_launch_args(**kwargs):
     import libtmux
+    from libtmux.pane import Pane
+    from libtmux.server import Server
+    from libtmux.session import Session
+    from libtmux.window import Window
 
     return {
         "libtmux": libtmux,
-        "Server": libtmux.Server,
-        "Session": libtmux.Session,
-        "Window": libtmux.Window,
-        "Pane": libtmux.Pane,
+        "Server": Server,
+        "Session": Session,
+        "Window": Window,
+        "Pane": Pane,
         "server": kwargs.get("server"),
         "session": kwargs.get("session"),
         "window": kwargs.get("window"),
@@ -208,15 +213,16 @@ def get_code(use_pythonrc, imported_objects):
     # We want to honor both $PYTHONSTARTUP and .pythonrc.py, so follow system
     # conventions and get $PYTHONSTARTUP first then .pythonrc.py.
     if use_pythonrc:
+        PYTHONSTARTUP = os.environ.get("PYTHONSTARTUP")
         for pythonrc in {
-            os.environ.get("PYTHONSTARTUP"),
-            os.path.expanduser("~/.pythonrc.py"),
+            *([pathlib.Path(PYTHONSTARTUP)] if PYTHONSTARTUP is not None else []),
+            pathlib.Path("~/.pythonrc.py").expanduser(),
         }:
             if not pythonrc:
                 continue
-            if not os.path.isfile(pythonrc):
+            if not pythonrc.is_file():
                 continue
-            with open(pythonrc) as handle:
+            with pythonrc.open() as handle:
                 pythonrc_code = handle.read()
             # Match the behavior of the cpython shell where an error in
             # PYTHONSTARTUP prints an exception and continues.
diff --git a/src/tmuxp/types.py b/src/tmuxp/types.py
index 536225c9f1d..f1f6c138f88 100644
--- a/src/tmuxp/types.py
+++ b/src/tmuxp/types.py
@@ -6,7 +6,7 @@
 :class:`StrPath` and :class:`StrOrBytesPath` is based on `typeshed's`_.
 
 .. _typeshed's: https://github.com/python/typeshed/blob/9687d5/stdlib/_typeshed/__init__.pyi#L98
-"""  # NOQA E501
+"""  # E501
 from os import PathLike
 from typing import Union
 
diff --git a/src/tmuxp/util.py b/src/tmuxp/util.py
index 90acacf05a7..8a306fbedf7 100644
--- a/src/tmuxp/util.py
+++ b/src/tmuxp/util.py
@@ -50,15 +50,20 @@ def run_before_script(
             stderr_str = "\n".join(list(filter(None, stderr_strlist)))  # filter empty
 
             raise exc.BeforeLoadScriptError(
-                proc.returncode, os.path.abspath(script_file), stderr_str
+                proc.returncode,
+                os.path.abspath(script_file),  # NOQA: PTH100
+                stderr_str,
             )
-
-        return proc.returncode
+        else:
+            return proc.returncode
     except OSError as e:
         if e.errno == 2:
-            raise exc.BeforeLoadScriptNotExists(e, os.path.abspath(script_file))
+            raise exc.BeforeLoadScriptNotExists(
+                e,
+                os.path.abspath(script_file),  # NOQA: PTH100
+            ) from e
         else:
-            raise e
+            raise
 
 
 def oh_my_zsh_auto_title() -> None:
@@ -66,29 +71,31 @@ def oh_my_zsh_auto_title() -> None:
 
     See: https://github.com/robbyrussell/oh-my-zsh/pull/257
     """
-    if "SHELL" in os.environ and "zsh" in os.environ.get("SHELL", ""):
-        if os.path.exists(os.path.expanduser("~/.oh-my-zsh")):
-            # oh-my-zsh exists
-            if (
-                "DISABLE_AUTO_TITLE" not in os.environ
-                or os.environ.get("DISABLE_AUTO_TITLE") == "false"
-            ):
-                print(
-                    "Please set:\n\n"
-                    "\texport DISABLE_AUTO_TITLE='true'\n\n"
-                    "in ~/.zshrc or where your zsh profile is stored.\n"
-                    'Remember the "export" at the beginning!\n\n'
-                    "Then create a new shell or type:\n\n"
-                    "\t$ source ~/.zshrc"
-                )
+    if (
+        "SHELL" in os.environ
+        and "zsh" in os.environ.get("SHELL", "")
+        and os.path.exists(os.path.expanduser("~/.oh-my-zsh"))  # NOQA PTH110, PTH111
+        and (
+            "DISABLE_AUTO_TITLE" not in os.environ
+            or os.environ.get("DISABLE_AUTO_TITLE") == "false"
+        )
+    ):
+        print(
+            "Please set:\n\n"
+            "\texport DISABLE_AUTO_TITLE='true'\n\n"
+            "in ~/.zshrc or where your zsh profile is stored.\n"
+            'Remember the "export" at the beginning!\n\n'
+            "Then create a new shell or type:\n\n"
+            "\t$ source ~/.zshrc"
+        )
 
 
 def get_current_pane(server: "Server") -> t.Optional["Pane"]:
     """Return Pane if one found in env"""
     if os.getenv("TMUX_PANE") is not None:
         try:
-            return [p for p in server.panes if p.pane_id == os.getenv("TMUX_PANE")][0]
-        except IndexError:
+            return next(p for p in server.panes if p.pane_id == os.getenv("TMUX_PANE"))
+        except StopIteration:
             pass
     return None
 
@@ -109,15 +116,13 @@ def get_session(
                 session = server.sessions.get(session_id=current_pane.session_id)
             else:
                 session = server.sessions[0]
-    except Exception:
-        session = None
 
-    if session is None:
+    except Exception as e:
         if session_name:
-            raise exc.TmuxpException("Session not found: %s" % session_name)
-        else:
-            raise exc.TmuxpException("Session not found")
+            raise exc.SessionNotFound(session_name) from e
+        raise exc.SessionNotFound() from e
 
+    assert session is not None
     return session
 
 
@@ -133,17 +138,14 @@ def get_window(
             window = session.windows.get(window_id=current_pane.window_id)
         else:
             window = session.windows[0]
-    except Exception:
-        window = None
-
-    if window is None:
+    except Exception as e:
         if window_name:
-            raise exc.TmuxpException("Window not found: %s" % window_name)
-        if current_pane:
-            raise exc.TmuxpException("Window not found: %s" % current_pane)
-        else:
-            raise exc.TmuxpException("Window not found")
+            raise exc.WindowNotFound(window_target=window_name) from e
+        elif current_pane:
+            raise exc.WindowNotFound(window_target=str(current_pane)) from e
+        raise exc.WindowNotFound() from e
 
+    assert window is not None
     return window
 
 
@@ -151,16 +153,15 @@ def get_pane(window: "Window", current_pane: t.Optional["Pane"] = None) -> "Pane
     pane = None
     try:
         if current_pane is not None:
-            pane = window.panes.get(pane_id=current_pane.pane_id)  # NOQA: F841
+            pane = window.panes.get(pane_id=current_pane.pane_id)
         else:
-            pane = window.attached_pane  # NOQA: F841
+            pane = window.attached_pane
     except exc.TmuxpException as e:
         print(e)
 
     if pane is None:
         if current_pane:
-            raise exc.TmuxpException("Pane not found: %s" % current_pane)
-        else:
-            raise exc.TmuxpException("Pane not found")
+            raise exc.PaneNotFound(str(current_pane))
+        raise exc.PaneNotFound()
 
     return pane
diff --git a/src/tmuxp/workspace/builder.py b/src/tmuxp/workspace/builder.py
index efd2f2fc6aa..b73a250fecd 100644
--- a/src/tmuxp/workspace/builder.py
+++ b/src/tmuxp/workspace/builder.py
@@ -141,7 +141,7 @@ def __init__(
         self,
         session_config: t.Dict[str, t.Any],
         server: Server,
-        plugins: t.List[t.Any] = [],
+        plugins: t.Optional[t.List[t.Any]] = None,
     ) -> None:
         """Initialize workspace loading.
 
@@ -162,8 +162,10 @@ def __init__(
         ``self.session``.
         """
 
+        if plugins is None:
+            plugins = []
         if not session_config:
-            raise exc.EmptyWorkspaceException("Session configuration is empty.")
+            raise exc.EmptyWorkspaceException()
 
         # validation.validate_schema(session_config)
 
@@ -188,10 +190,7 @@ def __init__(
     @property
     def session(self):
         if self._session is None:
-            raise ObjectDoesNotExist(
-                "No session object exists for WorkspaceBuilder. "
-                "Tip: Add session_name in constructor or run WorkspaceBuilder.build()"
-            )
+            raise exc.SessionMissingWorkspaceException()
         return self._session
 
     def session_exists(self, session_name: str) -> bool:
@@ -256,7 +255,7 @@ def build(self, session: t.Optional[Session] = None, append: bool = False) -> No
         assert session.server is not None
 
         self.server: "Server" = session.server
-        self.server.sessions
+        assert self.server.sessions is not None
         assert self.server.has_session(session.name)
         assert session.id
 
@@ -276,9 +275,9 @@ def build(self, session: t.Optional[Session] = None, append: bool = False) -> No
                 if "start_directory" in self.session_config:
                     cwd = self.session_config["start_directory"]
                 run_before_script(self.session_config["before_script"], cwd=cwd)
-            except Exception as e:
+            except Exception:
                 self.session.kill_session()
-                raise e
+                raise
 
         if "options" in self.session_config:
             for option, value in self.session_config["options"].items():
@@ -349,10 +348,7 @@ def iter_create_windows(
         for window_iterator, window_config in enumerate(
             self.session_config["windows"], start=1
         ):
-            if "window_name" not in window_config:
-                window_name = None
-            else:
-                window_name = window_config["window_name"]
+            window_name = window_config.get("window_name", None)
 
             is_first_window_pass = self.first_window_pass(
                 window_iterator, session, append
@@ -363,20 +359,14 @@ def iter_create_windows(
                 w1 = session.attached_window
                 w1.move_window("99")
 
-            if "start_directory" in window_config:
-                start_directory = window_config["start_directory"]
-            else:
-                start_directory = None
+            start_directory = window_config.get("start_directory", None)
 
             # If the first pane specifies a start_directory, use that instead.
             panes = window_config["panes"]
             if panes and "start_directory" in panes[0]:
                 start_directory = panes[0]["start_directory"]
 
-            if "window_shell" in window_config:
-                window_shell = window_config["window_shell"]
-            else:
-                window_shell = None
+            window_shell = window_config.get("window_shell", None)
 
             # If the first pane specifies a shell, use that instead.
             try:
@@ -462,7 +452,9 @@ def iter_create_panes(
                 pane = window.attached_pane
             else:
 
-                def get_pane_start_directory():
+                def get_pane_start_directory(
+                    pane_config: t.Dict[str, str], window_config: t.Dict[str, str]
+                ) -> t.Optional[str]:
                     if "start_directory" in pane_config:
                         return pane_config["start_directory"]
                     elif "start_directory" in window_config:
@@ -470,7 +462,9 @@ def get_pane_start_directory():
                     else:
                         return None
 
-                def get_pane_shell():
+                def get_pane_shell(
+                    pane_config: t.Dict[str, str], window_config: t.Dict[str, str]
+                ) -> t.Optional[str]:
                     if "shell" in pane_config:
                         return pane_config["shell"]
                     elif "window_shell" in window_config:
@@ -496,8 +490,14 @@ def get_pane_shell():
 
                 pane = window.split_window(
                     attach=True,
-                    start_directory=get_pane_start_directory(),
-                    shell=get_pane_shell(),
+                    start_directory=get_pane_start_directory(
+                        pane_config=pane_config,
+                        window_config=window_config,
+                    ),
+                    shell=get_pane_shell(
+                        pane_config=pane_config,
+                        window_config=window_config,
+                    ),
                     target=pane.id,
                     environment=environment,
                 )
@@ -564,7 +564,7 @@ def find_current_attached_session(self) -> Session:
         current_active_pane = get_current_pane(self.server)
 
         if current_active_pane is None:
-            raise exc.TmuxpException("No session active.")
+            raise exc.ActiveSessionMissingWorkspaceException()
 
         return next(
             (
diff --git a/src/tmuxp/workspace/finders.py b/src/tmuxp/workspace/finders.py
index 943de30bff6..16b805c498f 100644
--- a/src/tmuxp/workspace/finders.py
+++ b/src/tmuxp/workspace/finders.py
@@ -19,11 +19,7 @@
 
 def is_workspace_file(
     filename: str,
-    extensions: t.Union["ValidExtensions", t.List["ValidExtensions"]] = [
-        ".yml",
-        ".yaml",
-        ".json",
-    ],
+    extensions: t.Union["ValidExtensions", t.List["ValidExtensions"], None] = None,
 ) -> bool:
     """
     Return True if file has a valid workspace file type.
@@ -39,13 +35,15 @@ def is_workspace_file(
     -------
     bool
     """
+    if extensions is None:
+        extensions = [".yml", ".yaml", ".json"]
     extensions = [extensions] if isinstance(extensions, str) else extensions
     return any(filename.endswith(e) for e in extensions)
 
 
 def in_dir(
-    workspace_dir: t.Union[pathlib.Path, str] = os.path.expanduser("~/.tmuxp"),
-    extensions: t.List["ValidExtensions"] = [".yml", ".yaml", ".json"],
+    workspace_dir: t.Union[pathlib.Path, str, None] = None,
+    extensions: t.Optional[t.List["ValidExtensions"]] = None,
 ) -> t.List[str]:
     """
     Return a list of workspace_files in ``workspace_dir``.
@@ -61,11 +59,17 @@ def in_dir(
     -------
     list
     """
-    workspace_files = []
+    if workspace_dir is None:
+        workspace_dir = os.path.expanduser("~/.tmuxp")
 
-    for filename in os.listdir(workspace_dir):
-        if is_workspace_file(filename, extensions) and not filename.startswith("."):
-            workspace_files.append(filename)
+    if extensions is None:
+        extensions = [".yml", ".yaml", ".json"]
+
+    workspace_files = [
+        filename
+        for filename in os.listdir(workspace_dir)
+        if is_workspace_file(filename, extensions) and not filename.startswith(".")
+    ]
 
     return workspace_files
 
@@ -86,11 +90,11 @@ def in_cwd() -> t.List[str]:
     >>> sorted(in_cwd())
     ['.tmuxp.json', '.tmuxp.yaml']
     """
-    workspace_files = []
-
-    for filename in os.listdir(os.getcwd()):
-        if filename.startswith(".tmuxp") and is_workspace_file(filename):
-            workspace_files.append(filename)
+    workspace_files = [
+        filename
+        for filename in os.listdir(os.getcwd())
+        if filename.startswith(".tmuxp") and is_workspace_file(filename)
+    ]
 
     return workspace_files
 
diff --git a/src/tmuxp/workspace/freezer.py b/src/tmuxp/workspace/freezer.py
index b9b4ab9ddb3..8f38e7be4bd 100644
--- a/src/tmuxp/workspace/freezer.py
+++ b/src/tmuxp/workspace/freezer.py
@@ -1,6 +1,10 @@
+import typing as t
+
 from libtmux.pane import Pane
 from libtmux.session import Session
-import typing as t
+
+if t.TYPE_CHECKING:
+    from libtmux.window import Window
 
 
 def inline(workspace_dict):
@@ -23,7 +27,7 @@ def inline(workspace_dict):
     ):
         workspace_dict["shell_command"] = workspace_dict["shell_command"][0]
 
-        if len(workspace_dict.keys()) == int(1):
+        if len(workspace_dict.keys()) == 1:
             workspace_dict = workspace_dict["shell_command"]
     if (
         "shell_command_before" in workspace_dict
@@ -76,10 +80,10 @@ def freeze(session: Session) -> t.Dict[str, t.Any]:
 
         # If all panes have same path, set 'start_directory' instead
         # of using 'cd' shell commands.
-        def pane_has_same_path(pane: Pane) -> bool:
+        def pane_has_same_path(window: "Window", pane: Pane) -> bool:
             return window.panes[0].pane_current_path == pane.pane_current_path
 
-        if all(pane_has_same_path(pane=pane) for pane in window.panes):
+        if all(pane_has_same_path(window=window, pane=pane) for pane in window.panes):
             window_config["start_directory"] = window.panes[0].pane_current_path
 
         for pane in window.panes:
@@ -94,7 +98,7 @@ def pane_has_same_path(pane: Pane) -> bool:
 
             current_cmd = pane.pane_current_command
 
-            def filter_interpretters_and_shells() -> bool:
+            def filter_interpretters_and_shells(current_cmd: t.Optional[str]) -> bool:
                 return current_cmd is not None and (
                     current_cmd.startswith("-")
                     or any(
@@ -102,7 +106,7 @@ def filter_interpretters_and_shells() -> bool:
                     )
                 )
 
-            if filter_interpretters_and_shells():
+            if filter_interpretters_and_shells(current_cmd=current_cmd):
                 current_cmd = None
 
             if current_cmd:
diff --git a/src/tmuxp/workspace/importers.py b/src/tmuxp/workspace/importers.py
index b5eff6606ba..9f60208f28c 100644
--- a/src/tmuxp/workspace/importers.py
+++ b/src/tmuxp/workspace/importers.py
@@ -126,10 +126,7 @@ def import_teamocil(workspace_dict: t.Dict[str, t.Any]) -> t.Dict[str, t.Any]:
     if "session" in workspace_dict:
         workspace_dict = workspace_dict["session"]
 
-    if "name" in workspace_dict:
-        tmuxp_workspace["session_name"] = workspace_dict["name"]
-    else:
-        tmuxp_workspace["session_name"] = None
+    tmuxp_workspace["session_name"] = workspace_dict.get("name", None)
 
     if "root" in workspace_dict:
         tmuxp_workspace["start_directory"] = workspace_dict.pop("root")
@@ -144,10 +141,10 @@ def import_teamocil(workspace_dict: t.Dict[str, t.Any]) -> t.Dict[str, t.Any]:
 
         if "filters" in w:
             if "before" in w["filters"]:
-                for b in w["filters"]["before"]:
+                for _b in w["filters"]["before"]:
                     window_dict["shell_command_before"] = w["filters"]["before"]
             if "after" in w["filters"]:
-                for b in w["filters"]["after"]:
+                for _b in w["filters"]["after"]:
                     window_dict["shell_command_after"] = w["filters"]["after"]
 
         if "root" in w:
diff --git a/src/tmuxp/workspace/loader.py b/src/tmuxp/workspace/loader.py
index 9fc30330b3a..1668a554547 100644
--- a/src/tmuxp/workspace/loader.py
+++ b/src/tmuxp/workspace/loader.py
@@ -6,28 +6,28 @@
 """
 import logging
 import os
+import pathlib
 from typing import Dict
 
 logger = logging.getLogger(__name__)
 
 
-def expandshell(_path):
-    """
-    Return expanded path based on user's ``$HOME`` and ``env``.
+def expandshell(value: str) -> str:
+    """Returned wih variables expanded based on user's ``$HOME`` and ``env``.
 
-    :py:func:`os.path.expanduser` and :py:func:`os.path.expandvars`.
+    :py:func:`os.path.expanduser` and :py:fubasednc:`os.path.expandvars`.
 
     Parameters
     ----------
-    path : str
-        path to expand
+    value : str
+        value to expand
 
     Returns
     -------
     str
-        path with shell variables expanded
+        value with shell variables expanded
     """
-    return os.path.expandvars(os.path.expanduser(_path))
+    return os.path.expandvars(os.path.expanduser(value))  # NOQA: PTH111
 
 
 def expand_cmd(p: Dict) -> Dict:
@@ -48,9 +48,12 @@ def expand_cmd(p: Dict) -> Dict:
         if not cmds or any(a == cmds for a in [None, "blank", "pane"]):
             cmds = []
 
-        if isinstance(cmds, list) and len(cmds) == int(1):
-            if any(a in cmds for a in [None, "blank", "pane"]):
-                cmds = []
+        if (
+            isinstance(cmds, list)
+            and len(cmds) == 1
+            and any(a in cmds for a in [None, "blank", "pane"])
+        ):
+            cmds = []
 
         for cmd_idx, cmd in enumerate(cmds):
             if isinstance(cmd, str):
@@ -98,8 +101,7 @@ def expand(workspace_dict, cwd=None, parent=None):
 
     # Note: cli.py will expand workspaces relative to project's workspace directory
     # for the first cwd argument.
-    if not cwd:
-        cwd = os.getcwd()
+    cwd = pathlib.Path().cwd() if not cwd else pathlib.Path(cwd)
 
     if "session_name" in workspace_dict:
         workspace_dict["session_name"] = expandshell(workspace_dict["session_name"])
@@ -110,7 +112,7 @@ def expand(workspace_dict, cwd=None, parent=None):
             val = workspace_dict["environment"][key]
             val = expandshell(val)
             if any(val.startswith(a) for a in [".", "./"]):
-                val = os.path.normpath(os.path.join(cwd, val))
+                val = str(cwd / val)
             workspace_dict["environment"][key] = val
     if "global_options" in workspace_dict:
         for key in workspace_dict["global_options"]:
@@ -118,7 +120,7 @@ def expand(workspace_dict, cwd=None, parent=None):
             if isinstance(val, str):
                 val = expandshell(val)
                 if any(val.startswith(a) for a in [".", "./"]):
-                    val = os.path.normpath(os.path.join(cwd, val))
+                    val = str(cwd / val)
             workspace_dict["global_options"][key] = val
     if "options" in workspace_dict:
         for key in workspace_dict["options"]:
@@ -126,7 +128,7 @@ def expand(workspace_dict, cwd=None, parent=None):
             if isinstance(val, str):
                 val = expandshell(val)
                 if any(val.startswith(a) for a in [".", "./"]):
-                    val = os.path.normpath(os.path.join(cwd, val))
+                    val = str(cwd / val)
             workspace_dict["options"][key] = val
 
     # Any workspace section, session, window, pane that can contain the
@@ -144,16 +146,16 @@ def expand(workspace_dict, cwd=None, parent=None):
             # This is for the case where you may be loading a workspace from
             # outside your shell current directory.
             if parent:
-                cwd = parent["start_directory"]
-            start_path = os.path.normpath(os.path.join(cwd, start_path))
+                cwd = pathlib.Path(parent["start_directory"])
+
+            start_path = str((cwd / start_path).resolve(strict=False))
+
             workspace_dict["start_directory"] = start_path
 
     if "before_script" in workspace_dict:
         workspace_dict["before_script"] = expandshell(workspace_dict["before_script"])
         if any(workspace_dict["before_script"].startswith(a) for a in [".", "./"]):
-            workspace_dict["before_script"] = os.path.normpath(
-                os.path.join(cwd, workspace_dict["before_script"])
-            )
+            workspace_dict["before_script"] = str(cwd / workspace_dict["before_script"])
 
     if "shell_command" in workspace_dict and isinstance(
         workspace_dict["shell_command"], str
@@ -206,34 +208,29 @@ def trickle(workspace_dict):
     # prepends a pane's ``shell_command`` list with the window and sessions'
     # ``shell_command_before``.
 
-    if "start_directory" in workspace_dict:
-        session_start_directory = workspace_dict["start_directory"]
-    else:
-        session_start_directory = None
+    session_start_directory = workspace_dict.get("start_directory", None)
 
-    if "suppress_history" in workspace_dict:
-        suppress_history = workspace_dict["suppress_history"]
-    else:
-        suppress_history = None
+    suppress_history = workspace_dict.get("suppress_history", None)
 
     for window_dict in workspace_dict["windows"]:
         # Prepend start_directory to relative window commands
         if session_start_directory:
+            session_start_directory = session_start_directory
             if "start_directory" not in window_dict:
                 window_dict["start_directory"] = session_start_directory
             else:
                 if not any(
                     window_dict["start_directory"].startswith(a) for a in ["~", "/"]
                 ):
-                    window_start_path = os.path.join(
-                        session_start_directory, window_dict["start_directory"]
+                    window_start_path = (
+                        pathlib.Path(session_start_directory)
+                        / window_dict["start_directory"]
                     )
-                    window_dict["start_directory"] = window_start_path
+                    window_dict["start_directory"] = str(window_start_path)
 
         # We only need to trickle to the window, workspace builder checks wconf
-        if suppress_history is not None:
-            if "suppress_history" not in window_dict:
-                window_dict["suppress_history"] = suppress_history
+        if suppress_history is not None and "suppress_history" not in window_dict:
+            window_dict["suppress_history"] = suppress_history
 
         # If panes were NOT specified for a window, assume that a single pane
         # with no shell commands is desired
diff --git a/src/tmuxp/workspace/validation.py b/src/tmuxp/workspace/validation.py
index bbe1ede7f9e..02578e1de80 100644
--- a/src/tmuxp/workspace/validation.py
+++ b/src/tmuxp/workspace/validation.py
@@ -3,6 +3,48 @@
 from .. import exc
 
 
+class SchemaValidationError(exc.WorkspaceError):
+    pass
+
+
+class SessionNameMissingValidationError(SchemaValidationError):
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        return super().__init__(
+            'workspace requires "session_name"',
+            *args,
+            **kwargs,
+        )
+
+
+class WindowListMissingValidationError(SchemaValidationError):
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        return super().__init__(
+            'workspace requires list of "windows"',
+            *args,
+            **kwargs,
+        )
+
+
+class WindowNameMissingValidationError(SchemaValidationError):
+    def __init__(self, *args: object, **kwargs: object) -> None:
+        return super().__init__(
+            'workspace window is missing "window_name"',
+            *args,
+            **kwargs,
+        )
+
+
+class InvalidPluginsValidationError(SchemaValidationError):
+    def __init__(self, plugins: t.Any, *args: object, **kwargs: object) -> None:
+        return super().__init__(
+            '"plugins" only supports list type. '
+            + f" Received {type(plugins)}, "
+            + f"value: {plugins}",
+            *args,
+            **kwargs,
+        )
+
+
 def validate_schema(workspace_dict: t.Any) -> bool:
     """
     Return True if workspace schema is correct.
@@ -18,17 +60,16 @@ def validate_schema(workspace_dict: t.Any) -> bool:
     """
     # verify session_name
     if "session_name" not in workspace_dict:
-        raise exc.WorkspaceError('workspace requires "session_name"')
+        raise SessionNameMissingValidationError()
 
     if "windows" not in workspace_dict:
-        raise exc.WorkspaceError('workspace requires list of "windows"')
+        raise WindowListMissingValidationError()
 
     for window in workspace_dict["windows"]:
         if "window_name" not in window:
-            raise exc.WorkspaceError('workspace window is missing "window_name"')
+            raise WindowNameMissingValidationError()
 
-    if "plugins" in workspace_dict:
-        if not isinstance(workspace_dict["plugins"], list):
-            raise exc.WorkspaceError('"plugins" only supports list type')
+    if "plugins" in workspace_dict and not isinstance(workspace_dict["plugins"], list):
+        raise InvalidPluginsValidationError(plugins=workspace_dict.get("plugins"))
 
     return True
diff --git a/tests/cli/test_cli.py b/tests/cli/test_cli.py
index eacf8506973..ea49fb59fe7 100644
--- a/tests/cli/test_cli.py
+++ b/tests/cli/test_cli.py
@@ -1,12 +1,12 @@
 import argparse
-import os
+import contextlib
 import pathlib
 import typing as t
 
-import pytest
-
 import libtmux
+import pytest
 from libtmux.server import Server
+
 from tmuxp import cli
 from tmuxp.cli.import_config import get_teamocil_dir, get_tmuxinator_dir
 from tmuxp.cli.load import _reattach, load_plugins
@@ -26,7 +26,7 @@ def test_creates_config_dir_not_exists(tmp_path: pathlib.Path) -> None:
     """cli.startup() creates config dir if not exists."""
 
     cli.startup(tmp_path)
-    assert os.path.exists(tmp_path)
+    assert tmp_path.exists()
 
 
 @pytest.mark.parametrize(
@@ -42,10 +42,13 @@ def test_help(
     monkeypatch: pytest.MonkeyPatch,
     capsys: pytest.CaptureFixture,
 ) -> None:
-    try:
+    # In scrunched terminals, prevent width causing differantiation in result.out.
+    monkeypatch.setenv("COLUMNS", "100")
+    monkeypatch.setenv("LINES", "100")
+
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
+
     result = capsys.readouterr()
 
     assert "usage: tmuxp [-h] [--version] [--log-level log-level]" in result.out
@@ -56,26 +59,28 @@ def test_resolve_behavior(
 ) -> None:
     expect = tmp_path
     monkeypatch.chdir(tmp_path)
-    assert pathlib.Path("../").resolve() == pathlib.Path(os.path.dirname(expect))
-    assert pathlib.Path(".").resolve() == expect
+    assert pathlib.Path("../").resolve() == expect.parent
+    assert pathlib.Path().resolve() == expect
     assert pathlib.Path("./").resolve() == expect
     assert pathlib.Path(expect).resolve() == expect
 
 
 def test_get_tmuxinator_dir(monkeypatch: pytest.MonkeyPatch) -> None:
-    assert get_tmuxinator_dir() == os.path.expanduser("~/.tmuxinator/")
+    assert get_tmuxinator_dir() == pathlib.Path("~/.tmuxinator").expanduser()
 
     monkeypatch.setenv("HOME", "/moo")
-    assert get_tmuxinator_dir() == "/moo/.tmuxinator/"
-    assert get_tmuxinator_dir() == os.path.expanduser("~/.tmuxinator/")
+    assert get_tmuxinator_dir() == pathlib.Path("/moo/.tmuxinator/")
+    assert str(get_tmuxinator_dir()) == "/moo/.tmuxinator"
+    assert get_tmuxinator_dir() == pathlib.Path("~/.tmuxinator/").expanduser()
 
 
 def test_get_teamocil_dir(monkeypatch: pytest.MonkeyPatch) -> None:
-    assert get_teamocil_dir() == os.path.expanduser("~/.teamocil/")
+    assert get_teamocil_dir() == pathlib.Path("~/.teamocil/").expanduser()
 
     monkeypatch.setenv("HOME", "/moo")
-    assert get_teamocil_dir() == "/moo/.teamocil/"
-    assert get_teamocil_dir() == os.path.expanduser("~/.teamocil/")
+    assert get_teamocil_dir() == pathlib.Path("/moo/.teamocil/")
+    assert str(get_teamocil_dir()) == "/moo/.teamocil"
+    assert get_teamocil_dir() == pathlib.Path("~/.teamocil/").expanduser()
 
 
 def test_pass_config_dir_ClickPath(
@@ -129,10 +134,8 @@ def test_reattach_plugins(
     )
     builder.build()
 
-    try:
+    with contextlib.suppress(libtmux.exc.LibTmuxException):
         _reattach(builder)
-    except libtmux.exc.LibTmuxException:
-        pass
 
     assert builder.session is not None
     proc = builder.session.cmd("display-message", "-p", "'#S'")
diff --git a/tests/cli/test_convert.py b/tests/cli/test_convert.py
index b923c4ea1d2..6a36e3e46d6 100644
--- a/tests/cli/test_convert.py
+++ b/tests/cli/test_convert.py
@@ -1,3 +1,4 @@
+import contextlib
 import io
 import json
 import pathlib
@@ -41,10 +42,9 @@ def test_convert(
     input_args = "y\ny\n" if "-y" not in cli_args else ""
 
     monkeypatch.setattr("sys.stdin", io.StringIO(input_args))
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
+
     tmuxp_json = tmp_path / ".tmuxp.json"
     assert tmuxp_json.exists()
     assert tmuxp_json.open().read() == json.dumps({"session_name": "hello"}, indent=2)
@@ -76,10 +76,8 @@ def test_convert_json(
     input_args = "y\ny\n" if "-y" not in cli_args else ""
 
     monkeypatch.setattr("sys.stdin", io.StringIO(input_args))
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
 
     tmuxp_yaml = tmp_path / ".tmuxp.yaml"
     assert tmuxp_yaml.exists()
diff --git a/tests/cli/test_freeze.py b/tests/cli/test_freeze.py
index 87ddc58c143..9d5fac36e2a 100644
--- a/tests/cli/test_freeze.py
+++ b/tests/cli/test_freeze.py
@@ -1,10 +1,11 @@
+import contextlib
 import io
 import pathlib
 import typing as t
 
 import pytest
-
 from libtmux.server import Server
+
 from tmuxp import cli
 from tmuxp.config_reader import ConfigReader
 
@@ -47,13 +48,11 @@ def test_freeze(
     monkeypatch.chdir(tmp_path)
     # Use tmux server (socket name) used in the test
     assert server.socket_name is not None
-    cli_args = cli_args + ["-L", server.socket_name]
+    cli_args = [*cli_args, "-L", server.socket_name]
 
     monkeypatch.setattr("sys.stdin", io.StringIO("".join(inputs)))
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
 
     yaml_config_path = tmp_path / "la.yaml"
     assert yaml_config_path.exists()
@@ -93,13 +92,11 @@ def test_freeze_overwrite(
     monkeypatch.chdir(tmp_path)
     # Use tmux server (socket name) used in the test
     assert server.socket_name is not None
-    cli_args = cli_args + ["-L", server.socket_name]
+    cli_args = [*cli_args, "-L", server.socket_name]
 
     monkeypatch.setattr("sys.stdin", io.StringIO("".join(inputs)))
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
 
     yaml_config_path = tmp_path / "exists.yaml"
     assert yaml_config_path.exists()
diff --git a/tests/cli/test_import.py b/tests/cli/test_import.py
index 0d1e76a9220..ac8c295a4d9 100644
--- a/tests/cli/test_import.py
+++ b/tests/cli/test_import.py
@@ -1,3 +1,4 @@
+import contextlib
 import io
 import pathlib
 import typing as t
@@ -61,10 +62,8 @@ def test_import_teamocil(
     monkeypatch.chdir(tmp_path)
     monkeypatch.setattr("sys.stdin", io.StringIO("".join(inputs)))
 
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
 
     new_config_yaml = tmp_path / "la.yaml"
     assert new_config_yaml.exists()
@@ -109,10 +108,8 @@ def test_import_tmuxinator(
     monkeypatch.chdir(tmp_path)
 
     monkeypatch.setattr("sys.stdin", io.StringIO("".join(inputs)))
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
 
     new_config_yaml = tmp_path / "la.yaml"
     assert new_config_yaml.exists()
diff --git a/tests/cli/test_load.py b/tests/cli/test_load.py
index 6a42ce1ef75..aa341245ab3 100644
--- a/tests/cli/test_load.py
+++ b/tests/cli/test_load.py
@@ -1,15 +1,15 @@
+import contextlib
 import io
 import pathlib
 import typing as t
 
-import pytest
-
-from pytest_mock import MockerFixture
-
 import libtmux
+import pytest
 from libtmux.common import has_lt_version
 from libtmux.server import Server
 from libtmux.session import Session
+from pytest_mock import MockerFixture
+
 from tmuxp import cli
 from tmuxp.cli.load import (
     _load_append_windows_to_current_session,
@@ -282,22 +282,18 @@ def test_load(
             config_path.format(tmp_path=tmp_path, TMUXP_CONFIGDIR=tmuxp_configdir)
         )
         tmuxp_config.write_text(
-            """
+            f"""
         session_name: {session_name}
         windows:
         - window_name: test
           panes:
           -
-        """.format(
-                session_name=session_name
-            ),
+        """,
             encoding="utf-8",
         )
 
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli([*cli_args, "-d", "-L", server.socket_name, "-y"])
-    except SystemExit:
-        pass
 
     result = capsys.readouterr()
     output = "".join(list(result.out))
@@ -363,7 +359,7 @@ def test_load_zsh_autotitle_warning(
 
     # Use tmux server (socket name) used in the test
     assert server.socket_name is not None
-    cli_args = cli_args + ["-L", server.socket_name]
+    cli_args = [*cli_args, "-L", server.socket_name]
 
     cli.cli(cli_args)
     result = capsys.readouterr()
@@ -413,10 +409,9 @@ def test_load_log_file(
 
     monkeypatch.chdir(tmp_path)
 
-    try:
+    with contextlib.suppress(Exception):
         cli.cli(cli_args)
-    except Exception:
-        pass
+
     result = capsys.readouterr()
     log_file_path = tmp_path / "log.txt"
     assert "Loading" in log_file_path.open().read()
@@ -457,10 +452,9 @@ def test_load_plugins(monkeypatch_plugin_test_packages: None) -> None:
 def test_load_plugins_version_fail_skip(
     monkeypatch_plugin_test_packages, cli_args, inputs, capsys: pytest.CaptureFixture
 ) -> None:
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
+
     result = capsys.readouterr()
 
     assert "[Loading]" in result.out
@@ -484,10 +478,9 @@ def test_load_plugins_version_fail_no_skip(
 ) -> None:
     monkeypatch.setattr("sys.stdin", io.StringIO("".join(inputs)))
 
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
+
     result = capsys.readouterr()
 
     assert "[Not Skipping]" in result.out
@@ -502,10 +495,9 @@ def test_load_plugins_plugin_missing(
     cli_args: t.List[str],
     capsys: pytest.CaptureFixture,
 ) -> None:
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
+
     result = capsys.readouterr()
 
     assert "[Plugin Error]" in result.out
diff --git a/tests/cli/test_ls.py b/tests/cli/test_ls.py
index 75d6de7db54..89579d70937 100644
--- a/tests/cli/test_ls.py
+++ b/tests/cli/test_ls.py
@@ -1,4 +1,4 @@
-import os
+import contextlib
 import pathlib
 
 import pytest
@@ -27,7 +27,7 @@ def test_ls_cli(
     # - directories should be ignored
     # - extensions not covered in VALID_WORKSPACE_DIR_FILE_EXTENSIONS
     ignored_filenames = [".git/", ".gitignore/", "session_4.txt"]
-    stems = [os.path.splitext(f)[0] for f in filenames if f not in ignored_filenames]
+    stems = [pathlib.Path(f).stem for f in filenames if f not in ignored_filenames]
 
     for filename in filenames:
         location = tmp_path / f".tmuxp/{filename}"
@@ -36,10 +36,9 @@ def test_ls_cli(
         else:
             location.touch()
 
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(["ls"])
-    except SystemExit:
-        pass
+
     cli_output = capsys.readouterr().out
 
     assert cli_output == "\n".join(stems) + "\n"
diff --git a/tests/cli/test_shell.py b/tests/cli/test_shell.py
index 8dafac33462..c95d918c919 100644
--- a/tests/cli/test_shell.py
+++ b/tests/cli/test_shell.py
@@ -1,12 +1,13 @@
+import contextlib
 import io
 import pathlib
 import subprocess
 import typing as t
 
 import pytest
-
 from libtmux.server import Server
 from libtmux.session import Session
+
 from tmuxp import cli, exc
 
 
@@ -98,13 +99,13 @@ def test_shell(
 
     assert window.attached_pane is not None
 
-    template_ctx = dict(
-        SOCKET_NAME=server.socket_name,
-        SESSION_NAME=session.name,
-        WINDOW_NAME=window_name,
-        PANE_ID=window.attached_pane.id,
-        SERVER_SOCKET_NAME=server.socket_name,
-    )
+    template_ctx = {
+        "SOCKET_NAME": server.socket_name,
+        "SESSION_NAME": session.name,
+        "WINDOW_NAME": window_name,
+        "PANE_ID": window.attached_pane.id,
+        "SERVER_SOCKET_NAME": server.socket_name,
+    }
 
     cli_args = cli_cmd + [cli_arg.format(**template_ctx) for cli_arg in cli_args]
 
@@ -191,11 +192,11 @@ def test_shell_target_missing(
     assert session.name is not None
 
     template_ctx.update(
-        dict(
-            SOCKET_NAME=server.socket_name,
-            SESSION_NAME=session.name,
-            WINDOW_NAME=template_ctx.get("window_name", window_name),
-        )
+        {
+            "SOCKET_NAME": server.socket_name,
+            "SESSION_NAME": session.name,
+            "WINDOW_NAME": template_ctx.get("window_name", window_name),
+        }
     )
     cli_args = cli_cmd + [cli_arg.format(**template_ctx) for cli_arg in cli_args]
 
@@ -265,13 +266,13 @@ def test_shell_interactive(
 
     assert window.attached_pane is not None
 
-    template_ctx = dict(
-        SOCKET_NAME=server.socket_name,
-        SESSION_NAME=session.name,
-        WINDOW_NAME=window_name,
-        PANE_ID=window.attached_pane.id,
-        SERVER_SOCKET_NAME=server.socket_name,
-    )
+    template_ctx = {
+        "SOCKET_NAME": server.socket_name,
+        "SESSION_NAME": session.name,
+        "WINDOW_NAME": window_name,
+        "PANE_ID": window.attached_pane.id,
+        "SERVER_SOCKET_NAME": server.socket_name,
+    }
 
     cli_args = cli_cmd + [cli_arg.format(**template_ctx) for cli_arg in cli_args]
 
@@ -280,9 +281,8 @@ def test_shell_interactive(
 
     monkeypatch.chdir(tmp_path)
     monkeypatch.setattr("sys.stdin", io.StringIO("exit()\r"))
-    try:
+    with contextlib.suppress(SystemExit):
         cli.cli(cli_args)
-    except SystemExit:
-        pass
+
     result = capsys.readouterr()
     assert message.format(**template_ctx) in result.err
diff --git a/tests/fixtures/__init__.py b/tests/fixtures/__init__.py
index a81b5f2914d..eb018c3ff09 100644
--- a/tests/fixtures/__init__.py
+++ b/tests/fixtures/__init__.py
@@ -1 +1 @@
-from . import utils  # noqa
+from . import utils
diff --git a/tests/fixtures/import_teamocil/__init__.py b/tests/fixtures/import_teamocil/__init__.py
index 7fe671395a8..6d5ce91af9e 100644
--- a/tests/fixtures/import_teamocil/__init__.py
+++ b/tests/fixtures/import_teamocil/__init__.py
@@ -1 +1 @@
-from . import layouts, test1, test2, test3, test4  # noqa
+from . import layouts, test1, test2, test3, test4
diff --git a/tests/fixtures/import_tmuxinator/__init__.py b/tests/fixtures/import_tmuxinator/__init__.py
index bbdbf699ad0..91bc1d0f43e 100644
--- a/tests/fixtures/import_tmuxinator/__init__.py
+++ b/tests/fixtures/import_tmuxinator/__init__.py
@@ -1 +1 @@
-from . import test1, test2, test3  # noqa
+from . import test1, test2, test3
diff --git a/tests/fixtures/utils.py b/tests/fixtures/utils.py
index d6eb9cbbac4..858227c5b3a 100644
--- a/tests/fixtures/utils.py
+++ b/tests/fixtures/utils.py
@@ -10,13 +10,16 @@ def get_workspace_file(
     """Return fixture data, relative to __file__"""
     if isinstance(_file, str):
         _file = pathlib.Path(_file)
+
     return FIXTURE_PATH / _file
 
 
 def read_workspace_file(_file: t.Union[pathlib.Path, str]) -> str:
     """Return fixture data, relative to __file__"""
+    if isinstance(_file, str):
+        _file = pathlib.Path(_file)
 
-    return open(get_workspace_file(_file)).read()
+    return get_workspace_file(_file).open().read()
 
 
 def write_config(
diff --git a/tests/fixtures/workspace/__init__.py b/tests/fixtures/workspace/__init__.py
index 11692230916..097409c1569 100644
--- a/tests/fixtures/workspace/__init__.py
+++ b/tests/fixtures/workspace/__init__.py
@@ -1,4 +1,4 @@
-from . import (  # noqa
+from . import (
     expand1,
     expand2,
     expand_blank,
diff --git a/tests/fixtures/workspace/expand1.py b/tests/fixtures/workspace/expand1.py
index 4cd6c401aad..fa898a06b14 100644
--- a/tests/fixtures/workspace/expand1.py
+++ b/tests/fixtures/workspace/expand1.py
@@ -1,4 +1,4 @@
-import os
+import pathlib
 
 before_workspace = {
     "session_name": "sample workspace",
@@ -33,7 +33,7 @@
 def after_workspace():
     return {
         "session_name": "sample workspace",
-        "start_directory": os.path.expanduser("~"),
+        "start_directory": str(pathlib.Path().home()),
         "windows": [
             {
                 "window_name": "editor",
@@ -57,21 +57,15 @@ def after_workspace():
                 ],
             },
             {
-                "start_directory": os.path.normpath(
-                    os.path.join(os.path.expanduser("~"), "./")
-                ),
+                "start_directory": str(pathlib.Path().home()),
                 "panes": [{"shell_command": [{"cmd": "pwd"}]}],
             },
             {
-                "start_directory": os.path.normpath(
-                    os.path.join(os.path.expanduser("~"), "./asdf")
-                ),
+                "start_directory": str(pathlib.Path().home() / "asdf"),
                 "panes": [{"shell_command": [{"cmd": "pwd"}]}],
             },
             {
-                "start_directory": os.path.normpath(
-                    os.path.join(os.path.expanduser("~"), "../")
-                ),
+                "start_directory": str(pathlib.Path().home().parent.resolve()),
                 "panes": [{"shell_command": [{"cmd": "pwd"}]}],
             },
             {"panes": [{"shell_command": [{"cmd": "top"}]}]},
diff --git a/tests/fixtures/workspace/expand2.py b/tests/fixtures/workspace/expand2.py
index 3aa5bd3aa67..21f30403748 100644
--- a/tests/fixtures/workspace/expand2.py
+++ b/tests/fixtures/workspace/expand2.py
@@ -1,4 +1,4 @@
-import os
+import pathlib
 
 from .. import utils as test_utils
 
@@ -9,5 +9,5 @@ def unexpanded_yaml():
 
 def expanded_yaml():
     return test_utils.read_workspace_file("workspace/expand2-expanded.yaml").format(
-        HOME=os.path.expanduser("~")
+        HOME=str(pathlib.Path().home())
     )
diff --git a/tests/fixtures/workspace/shell_command_before.py b/tests/fixtures/workspace/shell_command_before.py
index a952a3db543..69f5c2f2b4e 100644
--- a/tests/fixtures/workspace/shell_command_before.py
+++ b/tests/fixtures/workspace/shell_command_before.py
@@ -1,5 +1,5 @@
-import os
-from typing import Any, Dict
+import pathlib
+import typing as t
 
 config_unexpanded = {  # shell_command_before is string in some areas
     "session_name": "sample workspace",
@@ -38,14 +38,14 @@
 }
 
 
-def config_expanded() -> Dict[str, Any]:
+def config_expanded() -> t.Dict[str, t.Any]:
     return {  # shell_command_before is string in some areas
         "session_name": "sample workspace",
         "start_directory": "/",
         "windows": [
             {
                 "window_name": "editor",
-                "start_directory": os.path.expanduser("~"),
+                "start_directory": str(pathlib.Path().home()),
                 "shell_command_before": {
                     "shell_command": [{"cmd": "source .venv/bin/activate"}]
                 },
@@ -90,14 +90,14 @@ def config_expanded() -> Dict[str, Any]:
     }
 
 
-def config_after() -> Dict[str, Any]:
+def config_after() -> t.Dict[str, t.Any]:
     return {  # shell_command_before is string in some areas
         "session_name": "sample workspace",
         "start_directory": "/",
         "windows": [
             {
                 "window_name": "editor",
-                "start_directory": os.path.expanduser("~"),
+                "start_directory": str(pathlib.Path().home()),
                 "shell_command_before": {
                     "shell_command": [{"cmd": "source .venv/bin/activate"}]
                 },
diff --git a/tests/tests/test_helpers.py b/tests/tests/test_helpers.py
index 0cb9ba21b83..5928f73937a 100644
--- a/tests/tests/test_helpers.py
+++ b/tests/tests/test_helpers.py
@@ -1,6 +1,5 @@
 """Tests for .'s helper and utility functions."""
 import pytest
-
 from libtmux.server import Server
 from libtmux.test import get_test_session_name, temp_session
 
diff --git a/tests/workspace/test_builder.py b/tests/workspace/test_builder.py
index 30d0e85ade4..111ff8b440c 100644
--- a/tests/workspace/test_builder.py
+++ b/tests/workspace/test_builder.py
@@ -1,18 +1,21 @@
 """Test for tmuxp workspacebuilder."""
+import functools
 import os
 import pathlib
 import textwrap
 import time
 import typing as t
 
-import pytest
-
 import libtmux
+import pytest
+from libtmux._internal.query_list import ObjectDoesNotExist
 from libtmux.common import has_gte_version, has_lt_version
+from libtmux.exc import LibTmuxException
 from libtmux.pane import Pane
 from libtmux.session import Session
 from libtmux.test import retry_until, temp_session
 from libtmux.window import Window
+
 from tmuxp import exc
 from tmuxp.cli.load import load_plugins
 from tmuxp.config_reader import ConfigReader
@@ -24,6 +27,11 @@
 
 if t.TYPE_CHECKING:
     from libtmux.server import Server
+    from typing_extensions import Protocol
+
+    class AssertCallbackProtocol(Protocol):
+        def __call__(self, cmd: str, hist: str) -> bool:
+            ...
 
 
 def test_split_windows(session):
@@ -87,15 +95,10 @@ def test_focus_pane_index(session):
     assert isinstance(_pane_base_index, int)
     pane_base_index = int(_pane_base_index)
 
-    if not pane_base_index:
-        pane_base_index = 0
-    else:
-        pane_base_index = int(pane_base_index)
+    pane_base_index = 0 if not pane_base_index else int(pane_base_index)
 
     # get the pane index for each pane
-    pane_base_indexes = []
-    for pane in session.attached_window.panes:
-        pane_base_indexes.append(int(pane.index))
+    pane_base_indexes = [int(pane.index) for pane in session.attached_window.panes]
 
     pane_indexes_should_be = [pane_base_index + x for x in range(0, 3)]
     assert pane_indexes_should_be == pane_base_indexes
@@ -182,7 +185,7 @@ def assertIsMissing(cmd, hist):
         buffer_name = "test"
         sent_cmd = None
 
-        def f():
+        def f(p: Pane, buffer_name: str, assertCase: AssertCallbackProtocol) -> bool:
             # from v0.7.4 libtmux session.cmd adds target -t self.id by default
             # show-buffer doesn't accept -t, use global cmd.
 
@@ -198,7 +201,9 @@ def f():
 
             return assertCase(sent_cmd, history_cmd)
 
-        assert retry_until(f), f"Unknown sent command: [{sent_cmd}] in {assertCase}"
+        _f = functools.partial(f, p=p, buffer_name=buffer_name, assertCase=assertCase)
+
+        assert retry_until(_f), f"Unknown sent command: [{sent_cmd}] in {assertCase}"
 
 
 def test_session_options(session):
@@ -231,7 +236,7 @@ def test_global_options(session):
     _status_position = session.show_option("status-position", _global=True)
     assert isinstance(_status_position, str)
     assert "top" in _status_position
-    assert 493 == session.show_option("repeat-time", _global=True)
+    assert session.show_option("repeat-time", _global=True) == 493
 
 
 def test_global_session_env_options(session, monkeypatch):
@@ -338,10 +343,12 @@ def test_window_shell(session):
         if "window_shell" in wconf:
             assert wconf["window_shell"] == "top"
 
-        def f():
+        def f(w: Window) -> bool:
             return w.window_name != "top"
 
-        retry_until(f)
+        _f = functools.partial(f, w=w)
+
+        retry_until(_f)
 
         assert w.name != "top"
 
@@ -530,12 +537,16 @@ def test_start_directory(session, tmp_path: pathlib.Path):
     for path, window in zip(dirs, session.windows):
         for p in window.panes:
 
-            def f():
+            def f(path: str, p: Pane) -> bool:
                 pane_path = p.pane_current_path
-                return path in pane_path or pane_path == path
+                return (
+                    pane_path is not None and path in pane_path
+                ) or pane_path == path
+
+            _f = functools.partial(f, path=path, p=p)
 
             # handle case with OS X adding /private/ to /tmp/ paths
-            assert retry_until(f)
+            assert retry_until(_f)
 
 
 def test_start_directory_relative(session, tmp_path: pathlib.Path):
@@ -567,8 +578,8 @@ def test_start_directory_relative(session, tmp_path: pathlib.Path):
 
     workspace = loader.trickle(workspace)
 
-    assert os.path.exists(config_dir)
-    assert os.path.exists(test_dir)
+    assert config_dir.exists()
+    assert test_dir.exists()
     builder = WorkspaceBuilder(session_config=workspace, server=session.server)
     builder.build(session=session)
 
@@ -579,12 +590,16 @@ def test_start_directory_relative(session, tmp_path: pathlib.Path):
     for path, window in zip(dirs, session.windows):
         for p in window.panes:
 
-            def f():
-                # Handle case where directories resolve to /private/ in OSX
+            def f(path: str, p: Pane) -> bool:
                 pane_path = p.pane_current_path
-                return path in pane_path or pane_path == path
+                return (
+                    pane_path is not None and path in pane_path
+                ) or pane_path == path
 
-            assert retry_until(f)
+            _f = functools.partial(f, path=path, p=p)
+
+            # handle case with OS X adding /private/ to /tmp/ paths
+            assert retry_until(_f)
 
 
 @pytest.mark.skipif(
@@ -603,7 +618,7 @@ def test_start_directory_sets_session_path(server):
     builder.build()
 
     session = builder.session
-    expected = "{0}|/usr".format(session.id)
+    expected = f"{session.id}|/usr"
 
     cmd = server.cmd("list-sessions", "-F", "#{session_id}|#{session_path}")
     assert expected in cmd.stdout
@@ -616,14 +631,14 @@ def test_pane_order(session):
     """
     yaml_workspace = test_utils.read_workspace_file(
         "workspace/builder/pane_ordering.yaml"
-    ).format(HOME=os.path.realpath(os.path.expanduser("~")))
+    ).format(HOME=str(pathlib.Path().home().resolve()))
 
     # test order of `panes` (and pane_index) above against pane_dirs
     pane_paths = [
         "/usr/bin",
         "/usr",
         "/etc",
-        os.path.realpath(os.path.expanduser("~")),
+        str(pathlib.Path().home().resolve()),
     ]
 
     workspace = ConfigReader._load(format="yaml", content=yaml_workspace)
@@ -636,7 +651,7 @@ def test_pane_order(session):
     assert len(session.windows) == window_count
 
     for w, wconf in builder.iter_create_windows(session):
-        for p in builder.iter_create_panes(w, wconf):
+        for _ in builder.iter_create_panes(w, wconf):
             w.select_layout("tiled")  # fix glitch with pane size
             assert len(session.windows) == window_count
 
@@ -654,11 +669,13 @@ def test_pane_order(session):
             # at 0 since python list.
             pane_path = pane_paths[p_index - pane_base_index]
 
-            def f():
+            def f(pane_path: str, p: Pane):
                 p.refresh()
                 return p.pane_current_path == pane_path
 
-            assert retry_until(f)
+            _f = functools.partial(f, pane_path=pane_path, p=p)
+
+            assert retry_until(_f)
 
 
 def test_window_index(session):
@@ -1268,12 +1285,14 @@ def test_first_pane_start_directory(session, tmp_path: pathlib.Path):
     window = session.windows[0]
     for path, p in zip(dirs, window.panes):
 
-        def f():
+        def f(path: str, p: Pane) -> bool:
             pane_path = p.pane_current_path
-            return path in pane_path or pane_path == path
+            return (pane_path is not None and path in pane_path) or pane_path == path
+
+        _f = functools.partial(f, path=path, p=p)
 
         # handle case with OS X adding /private/ to /tmp/ paths
-        assert retry_until(f)
+        assert retry_until(_f)
 
 
 @pytest.mark.skipif(
@@ -1384,7 +1403,14 @@ def test_issue_800_default_size_many_windows(
     builder = WorkspaceBuilder(session_config=workspace, server=server)
 
     if raises:
-        with pytest.raises(Exception):
+        with pytest.raises(
+            (
+                LibTmuxException,
+                exc.TmuxpException,
+                exc.EmptyWorkspaceException,
+                ObjectDoesNotExist,
+            )
+        ):
             builder.build()
 
         assert builder is not None
diff --git a/tests/workspace/test_config.py b/tests/workspace/test_config.py
index 4bc142b9ecb..436175d4d79 100644
--- a/tests/workspace/test_config.py
+++ b/tests/workspace/test_config.py
@@ -1,5 +1,4 @@
 """Test for tmuxp configuration import, inlining, expanding and export."""
-import os
 import pathlib
 import typing as t
 
@@ -44,14 +43,15 @@ def test_export_json(tmp_path: pathlib.Path, config_fixture: "WorkspaceTestData"
 # There's no tests for this
 #
 def test_find_workspace_file(tmp_path: pathlib.Path):
-    configs = []
+    configs = [str(tmp_path / x) for x in tmp_path.rglob("*.[json][ini][yaml]")]
 
     garbage_file = tmp_path / "config.psd"
     garbage_file.write_text("wat", encoding="utf-8")
 
-    for r, d, f in os.walk(str(tmp_path)):
-        for filela in (x for x in f if x.endswith((".json", ".ini", "yaml"))):
-            configs.append(str(tmp_path / filela))
+    # for _r, _d, f in os.walk(str(tmp_path)):
+    #     configs.extend(
+    #         [str(tmp_path / x) for x in f if x.endswith((".json", ".ini", "yaml"))]
+    #     )
 
     files = 0
     config_json = tmp_path / "config.json"
diff --git a/tests/workspace/test_finder.py b/tests/workspace/test_finder.py
index 1d64505a4a5..cdb33e7323a 100644
--- a/tests/workspace/test_finder.py
+++ b/tests/workspace/test_finder.py
@@ -53,8 +53,8 @@ def test_get_configs_cwd(
     confdir.mkdir()
 
     monkeypatch.chdir(confdir)
-    config1 = open(".tmuxp.json", "w+b")
-    config1.close()
+    with pathlib.Path(".tmuxp.json").open("w+b") as config1:
+        config1.close()
 
     configs_found = in_cwd()
     assert len(configs_found) == 1
@@ -153,13 +153,13 @@ def test_resolve_dot(
     assert find_workspace_file("myconfig") == str(user_config)
     assert find_workspace_file("~/.tmuxp/myconfig.yaml") == str(user_config)
 
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".tmuxp.json")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".tmuxp.ini")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("../")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("mooooooo")
 
     monkeypatch.chdir(homedir)
@@ -176,15 +176,15 @@ def test_resolve_dot(
     assert find_workspace_file("myconfig") == str(user_config)
     assert find_workspace_file("~/.tmuxp/myconfig.yaml") == str(user_config)
 
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".tmuxp.yaml")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("../")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("mooooooo")
 
     monkeypatch.chdir(configdir)
@@ -198,15 +198,15 @@ def test_resolve_dot(
     assert find_workspace_file("myconfig") == str(user_config)
     assert find_workspace_file("~/.tmuxp/myconfig.yaml") == str(user_config)
 
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".tmuxp.yaml")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("../")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("mooooooo")
 
     monkeypatch.chdir(tmp_path)
@@ -223,15 +223,15 @@ def test_resolve_dot(
     assert find_workspace_file("myconfig") == str(user_config)
     assert find_workspace_file("~/.tmuxp/myconfig.yaml") == str(user_config)
 
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file(".tmuxp.yaml")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("../")
-    with pytest.raises(Exception):
+    with pytest.raises(FileNotFoundError):
         find_workspace_file("mooooooo")