REF/TST: Add more pytest idiom to util/test_util (#24141)

Also breaks up test_util into multiple test modules
by the function or method tested.

Author: gfyoung

pandas/tests/util/test_deprecate_kwarg.py

@@ -0,0 +1,93 @@
+# -*- coding: utf-8 -*-
+import pytest
+
+from pandas.util._decorators import deprecate_kwarg
+
+import pandas.util.testing as tm
+
+
+@deprecate_kwarg("old", "new")
+def _f1(new=False):
+    return new
+
+
+_f2_mappings = {"yes": True, "no": False}
+
+
+@deprecate_kwarg("old", "new", _f2_mappings)
+def _f2(new=False):
+    return new
+
+
+def _f3_mapping(x):
+    return x + 1
+
+
+@deprecate_kwarg("old", "new", _f3_mapping)
+def _f3(new=0):
+    return new
+
+
+@pytest.mark.parametrize("key,klass", [
+    ("old", FutureWarning),
+    ("new", None)
+])
+def test_deprecate_kwarg(key, klass):
+    x = 78
+
+    with tm.assert_produces_warning(klass):
+        assert _f1(**{key: x}) == x
+
+
+@pytest.mark.parametrize("key", list(_f2_mappings.keys()))
+def test_dict_deprecate_kwarg(key):
+    with tm.assert_produces_warning(FutureWarning):
+        assert _f2(old=key) == _f2_mappings[key]
+
+
+@pytest.mark.parametrize("key", ["bogus", 12345, -1.23])
+def test_missing_deprecate_kwarg(key):
+    with tm.assert_produces_warning(FutureWarning):
+        assert _f2(old=key) == key
+
+
+@pytest.mark.parametrize("x", [1, -1.4, 0])
+def test_callable_deprecate_kwarg(x):
+    with tm.assert_produces_warning(FutureWarning):
+        assert _f3(old=x) == _f3_mapping(x)
+
+
+def test_callable_deprecate_kwarg_fail():
+    msg = "((can only|cannot) concatenate)|(must be str)|(Can't convert)"
+
+    with pytest.raises(TypeError, match=msg):
+        _f3(old="hello")
+
+
+def test_bad_deprecate_kwarg():
+    msg = "mapping from old to new argument values must be dict or callable!"
+
+    with pytest.raises(TypeError, match=msg):
+        @deprecate_kwarg("old", "new", 0)
+        def f4(new=None):
+            return new
+
+
+@deprecate_kwarg("old", None)
+def _f4(old=True, unchanged=True):
+    return old, unchanged
+
+
+@pytest.mark.parametrize("key", ["old", "unchanged"])
+def test_deprecate_keyword(key):
+    x = 9
+
+    if key == "old":
+        klass = FutureWarning
+        expected = (x, True)
+    else:
+        klass = None
+        expected = (True, x)
+
+    with tm.assert_produces_warning(klass):
+        assert _f4(**{key: x}) == expected

pandas/tests/util/test_locale.py

@@ -0,0 +1,94 @@
+# -*- coding: utf-8 -*-
+import codecs
+import locale
+import os
+
+import pytest
+
+from pandas.compat import is_platform_windows
+
+import pandas.core.common as com
+import pandas.util.testing as tm
+
+_all_locales = tm.get_locales() or []
+_current_locale = locale.getlocale()
+
+# Don't run any of these tests if we are on Windows or have no locales.
+pytestmark = pytest.mark.skipif(is_platform_windows() or not _all_locales,
+                                reason="Need non-Windows and locales")
+
+_skip_if_only_one_locale = pytest.mark.skipif(
+    len(_all_locales) <= 1, reason="Need multiple locales for meaningful test")
+
+
+def test_can_set_locale_valid_set():
+    # Can set the default locale.
+    assert tm.can_set_locale("")
+
+
+def test_can_set_locale_invalid_set():
+    # Cannot set an invalid locale.
+    assert not tm.can_set_locale("non-existent_locale")
+
+
+def test_can_set_locale_invalid_get(monkeypatch):
+    # see gh-22129
+    #
+    # In some cases, an invalid locale can be set,
+    # but a subsequent getlocale() raises a ValueError.
+
+    def mock_get_locale():
+        raise ValueError()
+
+    with monkeypatch.context() as m:
+        m.setattr(locale, "getlocale", mock_get_locale)
+        assert not tm.can_set_locale("")
+
+
+def test_get_locales_at_least_one():
+    # see gh-9744
+    assert len(_all_locales) > 0
+
+
+@_skip_if_only_one_locale
+def test_get_locales_prefix():
+    first_locale = _all_locales[0]
+    assert len(tm.get_locales(prefix=first_locale[:2])) > 0
+
+
+@_skip_if_only_one_locale
+def test_set_locale():
+    if com._all_none(_current_locale):
+        # Not sure why, but on some Travis runs with pytest,
+        # getlocale() returned (None, None).
+        pytest.skip("Current locale is not set.")
+
+    locale_override = os.environ.get("LOCALE_OVERRIDE", None)
+
+    if locale_override is None:
+        lang, enc = "it_CH", "UTF-8"
+    elif locale_override == "C":
+        lang, enc = "en_US", "ascii"
+    else:
+        lang, enc = locale_override.split(".")
+
+    enc = codecs.lookup(enc).name
+    new_locale = lang, enc
+
+    if not tm.can_set_locale(new_locale):
+        msg = "unsupported locale setting"
+
+        with pytest.raises(locale.Error, match=msg):
+            with tm.set_locale(new_locale):
+                pass
+    else:
+        with tm.set_locale(new_locale) as normalized_locale:
+            new_lang, new_enc = normalized_locale.split(".")
+            new_enc = codecs.lookup(enc).name
+
+            normalized_locale = new_lang, new_enc
+            assert normalized_locale == new_locale
+
+    # Once we exit the "with" statement, locale should be back to what it was.
+    current_locale = locale.getlocale()
+    assert current_locale == _current_locale

pandas/tests/util/test_move.py

@@ -0,0 +1,79 @@
+# -*- coding: utf-8 -*-
+import sys
+from uuid import uuid4
+
+import pytest
+
+from pandas.compat import PY3, intern
+from pandas.util._move import BadMove, move_into_mutable_buffer, stolenbuf
+
+
+def test_cannot_create_instance_of_stolen_buffer():
+    # Stolen buffers need to be created through the smart constructor
+    # "move_into_mutable_buffer," which has a bunch of checks in it.
+
+    msg = "cannot create 'pandas.util._move.stolenbuf' instances"
+    with pytest.raises(TypeError, match=msg):
+        stolenbuf()
+
+
+def test_more_than_one_ref():
+    # Test case for when we try to use "move_into_mutable_buffer"
+    # when the object being moved has other references.
+
+    b = b"testing"
+
+    with pytest.raises(BadMove) as e:
+        def handle_success(type_, value, tb):
+            assert value.args[0] is b
+            return type(e).handle_success(e, type_, value, tb)  # super
+
+        e.handle_success = handle_success
+        move_into_mutable_buffer(b)
+
+
+def test_exactly_one_ref():
+    # Test case for when the object being moved has exactly one reference.
+
+    b = b"testing"
+
+    # We need to pass an expression on the stack to ensure that there are
+    # not extra references hanging around. We cannot rewrite this test as
+    #   buf = b[:-3]
+    #   as_stolen_buf = move_into_mutable_buffer(buf)
+    # because then we would have more than one reference to buf.
+    as_stolen_buf = move_into_mutable_buffer(b[:-3])
+
+    # Materialize as byte-array to show that it is mutable.
+    assert bytearray(as_stolen_buf) == b"test"
+
+
+@pytest.mark.skipif(PY3, reason="bytes objects cannot be interned in PY3")
+def test_interned():
+    salt = uuid4().hex
+
+    def make_string():
+        # We need to actually create a new string so that it has refcount
+        # one. We use a uuid so that we know the string could not already
+        # be in the intern table.
+        return "".join(("testing: ", salt))
+
+    # This should work, the string has one reference on the stack.
+    move_into_mutable_buffer(make_string())
+    refcount = [None]  # nonlocal
+
+    def ref_capture(ob):
+        # Subtract two because those are the references owned by this frame:
+        #   1. The local variables of this stack frame.
+        #   2. The python data stack of this stack frame.
+        refcount[0] = sys.getrefcount(ob) - 2
+        return ob
+
+    with pytest.raises(BadMove, match="testing"):
+        # If we intern the string, it will still have one reference. Now,
+        # it is in the intern table, so if other people intern the same
+        # string while the mutable buffer holds the first string they will
+        # be the same instance.
+        move_into_mutable_buffer(ref_capture(intern(make_string())))  # noqa
+
+    assert refcount[0] == 1

pandas/tests/util/test_safe_import.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+import sys
+import types
+
+import pytest
+
+import pandas.util._test_decorators as td
+
+
+@pytest.mark.parametrize("name", ["foo", "hello123"])
+def test_safe_import_non_existent(name):
+    assert not td.safe_import(name)
+
+
+def test_safe_import_exists():
+    assert td.safe_import("pandas")
+
+
+@pytest.mark.parametrize("min_version,valid", [
+    ("0.0.0", True),
+    ("99.99.99", False)
+])
+def test_safe_import_versions(min_version, valid):
+    result = td.safe_import("pandas", min_version=min_version)
+    result = result if valid else not result
+    assert result
+
+
+@pytest.mark.parametrize("min_version,valid", [
+    (None, False),
+    ("1.0", True),
+    ("2.0", False)
+])
+def test_safe_import_dummy(monkeypatch, min_version, valid):
+    mod_name = "hello123"
+
+    mod = types.ModuleType(mod_name)
+    mod.__version__ = "1.5"
+
+    if min_version is not None:
+        monkeypatch.setitem(sys.modules, mod_name, mod)
+
+    result = td.safe_import(mod_name, min_version=min_version)
+    result = result if valid else not result
+    assert result