From 7ab927948e15551410a3e56b5222d23dc6c4522a Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 11:39:11 -0300
Subject: [PATCH 01/22] Accepts integer/float string with units and raises when
 unit is ambiguous.

---
 pandas/_libs/tslibs/timedeltas.pyx            | 214 +++++-------------
 .../scalar/timedelta/test_construction.py     |  27 +++
 2 files changed, 80 insertions(+), 161 deletions(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index 9c8be1901d1dc..cb0534cbb6d0d 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+# cython: profile=False
 import collections
 import textwrap
 import warnings
@@ -6,13 +7,13 @@ import warnings
 import sys
 cdef bint PY3 = (sys.version_info[0] >= 3)
 
-from cython import Py_ssize_t
+from cython cimport Py_ssize_t
 
-from cpython cimport Py_NE, Py_EQ, PyObject_RichCompare
+from cpython cimport PyUnicode_Check, Py_NE, Py_EQ, PyObject_RichCompare
 
 import numpy as np
 cimport numpy as cnp
-from numpy cimport int64_t
+from numpy cimport int64_t, ndarray
 cnp.import_array()
 
 from cpython.datetime cimport (datetime, timedelta,
@@ -32,7 +33,6 @@ from np_datetime cimport (cmp_scalar, reverse_ops, td64_to_tdstruct,
 
 from nattype import nat_strings, NaT
 from nattype cimport checknull_with_nat, NPY_NAT
-from offsets cimport to_offset
 
 # ----------------------------------------------------------------------
 # Constants
@@ -78,44 +78,6 @@ cdef dict timedelta_abbrevs = { 'D': 'd',
 
 _no_input = object()
 
-
-# ----------------------------------------------------------------------
-# API
-
-def ints_to_pytimedelta(int64_t[:] arr, box=False):
-    """
-    convert an i8 repr to an ndarray of timedelta or Timedelta (if box ==
-    True)
-
-    Parameters
-    ----------
-    arr : ndarray[int64_t]
-    box : bool, default False
-
-    Returns
-    -------
-    result : ndarray[object]
-        array of Timedelta or timedeltas objects
-    """
-    cdef:
-        Py_ssize_t i, n = len(arr)
-        int64_t value
-        object[:] result = np.empty(n, dtype=object)
-
-    for i in range(n):
-
-        value = arr[i]
-        if value == NPY_NAT:
-            result[i] = NaT
-        else:
-            if box:
-                result[i] = Timedelta(value)
-            else:
-                result[i] = timedelta(microseconds=int(value) / 1000)
-
-    return result.base  # .base to access underlying np.ndarray
-
-
 # ----------------------------------------------------------------------
 
 cpdef int64_t delta_to_nanoseconds(delta) except? -1:
@@ -161,7 +123,7 @@ cpdef convert_to_timedelta64(object ts, object unit):
         if ts.astype('int64') == NPY_NAT:
             return np.timedelta64(NPY_NAT)
     elif is_timedelta64_object(ts):
-        ts = ts.astype("m8[{unit}]".format(unit=unit.lower()))
+        ts = ts.astype("m8[{0}]".format(unit.lower()))
     elif is_integer_object(ts):
         if ts == NPY_NAT:
             return np.timedelta64(NPY_NAT)
@@ -182,11 +144,7 @@ cpdef convert_to_timedelta64(object ts, object unit):
             ts = cast_from_unit(ts, unit)
             ts = np.timedelta64(ts)
     elif is_string_object(ts):
-        if len(ts) > 0 and ts[0] == 'P':
-            ts = parse_iso_format_string(ts)
-        else:
-            ts = parse_timedelta_string(ts)
-        ts = np.timedelta64(ts)
+        ts = np.timedelta64(parse_timedelta_string(ts))
     elif hasattr(ts, 'delta'):
         ts = np.timedelta64(delta_to_nanoseconds(ts), 'ns')
 
@@ -198,7 +156,7 @@ cpdef convert_to_timedelta64(object ts, object unit):
     return ts.astype('timedelta64[ns]')
 
 
-cpdef array_to_timedelta64(object[:] values, unit='ns', errors='raise'):
+cpdef array_to_timedelta64(ndarray[object] values, unit='ns', errors='raise'):
     """
     Convert an ndarray to an array of timedeltas. If errors == 'coerce',
     coerce non-convertible objects to NaT. Otherwise, raise.
@@ -206,7 +164,7 @@ cpdef array_to_timedelta64(object[:] values, unit='ns', errors='raise'):
 
     cdef:
         Py_ssize_t i, n
-        int64_t[:] iresult
+        ndarray[int64_t] iresult
 
     if errors not in ('ignore', 'raise', 'coerce'):
         raise ValueError("errors must be one of 'ignore', "
@@ -232,7 +190,7 @@ cpdef array_to_timedelta64(object[:] values, unit='ns', errors='raise'):
                 else:
                     raise
 
-    return iresult.base  # .base to access underlying np.ndarray
+    return iresult
 
 
 cpdef inline int64_t cast_from_unit(object ts, object unit) except? -1:
@@ -264,7 +222,7 @@ cpdef inline int64_t cast_from_unit(object ts, object unit) except? -1:
         m = 1L
         p = 0
     else:
-        raise ValueError("cannot cast unit {unit}".format(unit=unit))
+        raise ValueError("cannot cast unit {0}".format(unit))
 
     # just give me the unit back
     if ts is None:
@@ -272,22 +230,22 @@ cpdef inline int64_t cast_from_unit(object ts, object unit) except? -1:
 
     # cast the unit, multiply base/frace separately
     # to avoid precision issues from float -> int
-    base = <int64_t>ts
+    base = <int64_t> ts
     frac = ts - base
     if p:
         frac = round(frac, p)
-    return <int64_t>(base * m) + <int64_t>(frac * m)
+    return <int64_t> (base * m) + <int64_t> (frac * m)
 
 
 cdef inline _decode_if_necessary(object ts):
     # decode ts if necessary
-    if not isinstance(ts, unicode) and not PY3:
+    if not PyUnicode_Check(ts) and not PY3:
         ts = str(ts).decode('utf-8')
 
     return ts
 
 
-cdef inline parse_timedelta_string(object ts):
+cdef inline parse_timedelta_string(object ts, object specified_unit=None):
     """
     Parse a regular format timedelta string. Return an int64_t (in ns)
     or raise a ValueError on an invalid parse.
@@ -295,10 +253,11 @@ cdef inline parse_timedelta_string(object ts):
 
     cdef:
         unicode c
-        bint neg = 0, have_dot = 0, have_value = 0, have_hhmmss = 0
-        object current_unit = None
-        int64_t result = 0, m = 0, r
-        list number = [], frac = [], unit = []
+        bint neg=0, have_dot=0, have_value=0, have_hhmmss=0
+        object current_unit=None
+        object fallback_unit=None
+        int64_t result=0, m=0, r
+        list number=[], frac=[], unit=[]
 
     # neg : tracks if we have a leading negative for the value
     # have_dot : tracks if we are processing a dot (either post hhmmss or
@@ -373,7 +332,7 @@ cdef inline parse_timedelta_string(object ts):
                 have_hhmmss = 1
             else:
                 raise ValueError("expecting hh:mm:ss format, "
-                                 "received: {ts}".format(ts=ts))
+                                 "received: {0}".format(ts))
 
             unit, number = [], []
 
@@ -448,9 +407,16 @@ cdef inline parse_timedelta_string(object ts):
         if have_value:
             raise ValueError("have leftover units")
         if len(number):
-            r = timedelta_from_spec(number, frac, 'ns')
+            if specified_unit is None:
+                fallback_unit = 'ns'
+            else:
+                fallback_unit = specified_unit
+            r = timedelta_from_spec(number, frac, fallback_unit)
             result += timedelta_as_neg(r, neg)
 
+    if (specified_unit is not None) and (fallback_unit is None):
+        raise ValueError("unit was specified but is redundant/ambiguous")
+
     return result
 
 
@@ -482,7 +448,7 @@ cdef inline timedelta_from_spec(object number, object frac, object unit):
         unit = ''.join(unit)
         unit = timedelta_abbrevs[unit.lower()]
     except KeyError:
-        raise ValueError("invalid abbreviation: {unit}".format(unit=unit))
+        raise ValueError("invalid abbreviation: {0}".format(unit))
 
     n = ''.join(number) + '.' + ''.join(frac)
     return cast_from_unit(float(n), unit)
@@ -541,12 +507,10 @@ def _binary_op_method_timedeltalike(op, name):
 
         elif hasattr(other, 'dtype'):
             # nd-array like
-            if other.dtype.kind in ['m', 'M']:
-                return op(self.to_timedelta64(), other)
-            elif other.dtype.kind == 'O':
-                return np.array([op(self, x) for x in other])
-            else:
+            if other.dtype.kind not in ['m', 'M']:
+                # raise rathering than letting numpy return wrong answer
                 return NotImplemented
+            return op(self.to_timedelta64(), other)
 
         elif not _validate_ops_compat(other):
             return NotImplemented
@@ -593,10 +557,10 @@ cdef inline int64_t parse_iso_format_string(object ts) except? -1:
     cdef:
         unicode c
         int64_t result = 0, r
-        int p = 0
+        int p=0
         object dec_unit = 'ms', err_msg
-        bint have_dot = 0, have_value = 0, neg = 0
-        list number = [], unit = []
+        bint have_dot=0, have_value=0, neg=0
+        list number=[], unit=[]
 
     ts = _decode_if_necessary(ts)
 
@@ -683,8 +647,8 @@ cdef _to_py_int_float(v):
         return int(v)
     elif is_float_object(v):
         return float(v)
-    raise TypeError("Invalid type {typ}. Must be int or "
-                    "float.".format(typ=type(v)))
+    raise TypeError("Invalid type {0}. Must be int or "
+                    "float.".format(type(v)))
 
 
 # Similar to Timestamp/datetime, this is a construction requirement for
@@ -730,10 +694,9 @@ cdef class _Timedelta(timedelta):
                             return True
 
                         # only allow ==, != ops
-                        raise TypeError('Cannot compare type {cls} with '
-                                        'type {other}'
-                                        .format(cls=type(self).__name__,
-                                                other=type(other).__name__))
+                        raise TypeError('Cannot compare type {!r} with type ' \
+                                        '{!r}'.format(type(self).__name__,
+                                                      type(other).__name__))
                 if util.is_array(other):
                     return PyObject_RichCompare(np.array([self]), other, op)
                 return PyObject_RichCompare(other, self, reverse_ops[op])
@@ -742,9 +705,9 @@ cdef class _Timedelta(timedelta):
                     return False
                 elif op == Py_NE:
                     return True
-                raise TypeError('Cannot compare type {cls} with type {other}'
-                                .format(cls=type(self).__name__,
-                                        other=type(other).__name__))
+                raise TypeError('Cannot compare type {!r} with type ' \
+                                '{!r}'.format(type(self).__name__,
+                                              type(other).__name__))
 
         return cmp_scalar(self.value, ots.value, op)
 
@@ -835,81 +798,12 @@ cdef class _Timedelta(timedelta):
 
     @property
     def asm8(self):
-        """
-        Return a numpy timedelta64 array scalar view.
-
-        Provides access to the array scalar view (i.e. a combination of the
-        value and the units) associated with the numpy.timedelta64().view(),
-        including a 64-bit integer representation of the timedelta in
-        nanoseconds (Python int compatible).
-
-        Returns
-        -------
-        numpy timedelta64 array scalar view
-            Array scalar view of the timedelta in nanoseconds.
-
-        Examples
-        --------
-        >>> td = pd.Timedelta('1 days 2 min 3 us 42 ns')
-        >>> td.asm8
-        numpy.timedelta64(86520000003042,'ns')
-
-        >>> td = pd.Timedelta('2 min 3 s')
-        >>> td.asm8
-        numpy.timedelta64(123000000000,'ns')
-
-        >>> td = pd.Timedelta('3 ms 5 us')
-        >>> td.asm8
-        numpy.timedelta64(3005000,'ns')
-
-        >>> td = pd.Timedelta(42, unit='ns')
-        >>> td.asm8
-        numpy.timedelta64(42,'ns')
-        """
+        """ return a numpy timedelta64 array view of myself """
         return np.int64(self.value).view('m8[ns]')
 
     @property
     def resolution(self):
-        """
-        Return a string representing the lowest timedelta resolution.
-
-        Each timedelta has a defined resolution that represents the lowest OR
-        most granular level of precision. Each level of resolution is
-        represented by a short string as defined below:
-
-        Resolution:     Return value
-
-        * Days:         'D'
-        * Hours:        'H'
-        * Minutes:      'T'
-        * Seconds:      'S'
-        * Milliseconds: 'L'
-        * Microseconds: 'U'
-        * Nanoseconds:  'N'
-
-        Returns
-        -------
-        str
-            Timedelta resolution.
-
-        Examples
-        --------
-        >>> td = pd.Timedelta('1 days 2 min 3 us 42 ns')
-        >>> td.resolution
-        'N'
-
-        >>> td = pd.Timedelta('1 days 2 min 3 us')
-        >>> td.resolution
-        'U'
-
-        >>> td = pd.Timedelta('2 min 3 s')
-        >>> td.resolution
-        'S'
-
-        >>> td = pd.Timedelta(36, unit='us')
-        >>> td.resolution
-        'U'
-        """
+        """ return a string representing the lowest resolution that we have """
 
         self._ensure_components()
         if self._ns:
@@ -931,7 +825,7 @@ cdef class _Timedelta(timedelta):
     def nanoseconds(self):
         """
         Return the number of nanoseconds (n), where 0 <= n < 1 microsecond.
-
+       
         Returns
         -------
         int
@@ -982,8 +876,8 @@ cdef class _Timedelta(timedelta):
             sign = " "
 
         if format == 'all':
-            fmt = ("{days} days{sign}{hours:02}:{minutes:02}:{seconds:02}."
-                   "{milliseconds:03}{microseconds:03}{nanoseconds:03}")
+            fmt = "{days} days{sign}{hours:02}:{minutes:02}:{seconds:02}." \
+                  "{milliseconds:03}{microseconds:03}{nanoseconds:03}"
         else:
             # if we have a partial day
             subs = (self._h or self._m or self._s or
@@ -1008,14 +902,11 @@ cdef class _Timedelta(timedelta):
         return fmt.format(**comp_dict)
 
     def __repr__(self):
-        return "Timedelta('{val}')".format(val=self._repr_base(format='long'))
+        return "Timedelta('{0}')".format(self._repr_base(format='long'))
 
     def __str__(self):
         return self._repr_base(format='long')
 
-    def __bool__(self):
-        return self.value != 0
-
     def isoformat(self):
         """
         Format Timedelta as ISO 8601 Duration like
@@ -1062,8 +953,8 @@ cdef class _Timedelta(timedelta):
                                                  components.nanoseconds)
         # Trim unnecessary 0s, 1.000000000 -> 1
         seconds = seconds.rstrip('0').rstrip('.')
-        tpl = ('P{td.days}DT{td.hours}H{td.minutes}M{seconds}S'
-               .format(td=components, seconds=seconds))
+        tpl = 'P{td.days}DT{td.hours}H{td.minutes}M{seconds}S'.format(
+            td=components, seconds=seconds)
         return tpl
 
 
@@ -1164,6 +1055,7 @@ class Timedelta(_Timedelta):
         cdef:
             int64_t result, unit
 
+        from pandas.tseries.frequencies import to_offset
         unit = to_offset(freq).nanos
         result = unit * rounder(self.value / float(unit))
         return Timedelta(result, unit='ns')
@@ -1370,7 +1262,7 @@ class Timedelta(_Timedelta):
                             '{op}'.format(dtype=other.dtype,
                                           op='__floordiv__'))
 
-        elif is_float_object(other) and util.is_nan(other):
+        elif is_float_object(other) and util._checknull(other):
             # i.e. np.nan
             return NotImplemented
 
diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index d648140aa7347..0283b70350bf6 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -210,3 +210,30 @@ def test_td_constructor_on_nanoseconds(constructed_td, conversion):
 def test_td_constructor_value_error():
     with pytest.raises(TypeError):
         Timedelta(nanoseconds='abc')
+
+
+class not_raises(object):
+    def __enter__(self):
+        pass
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        pass
+
+
+@pytest.mark.parametrize("redundant_unit, expectation", [
+    ("", not_raises()),
+    ("d", pytest.raises(ValueError)),
+    ("us", pytest.raises(ValueError)),
+])
+@pytest.mark.parametrize("unit", [
+   "d", "m", "s", "us"
+])
+@pytest.mark.parametrize("sign", [
+   +1, -1
+])
+@pytest.mark.parametrize("num", [
+    0.001, 1, 10
+])
+def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
+    with expectation:
+        assert Timedelta(str(sign*num)+redundant_unit, unit=unit) == Timedelta(sign*num, unit=unit)

From 98a41f45760b5257c2e95a341c3fbd7c1cef8b0a Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 11:49:54 -0300
Subject: [PATCH 02/22] Fixed PEP linting.

---
 .../tests/scalar/timedelta/test_construction.py   | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 0283b70350bf6..451c8df4c39fb 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -223,17 +223,14 @@ def __exit__(self, exc_type, exc_val, exc_tb):
 @pytest.mark.parametrize("redundant_unit, expectation", [
     ("", not_raises()),
     ("d", pytest.raises(ValueError)),
-    ("us", pytest.raises(ValueError)),
-])
+    ("us", pytest.raises(ValueError))])
 @pytest.mark.parametrize("unit", [
-   "d", "m", "s", "us"
-])
+   "d", "m", "s", "us"])
 @pytest.mark.parametrize("sign", [
-   +1, -1
-])
+   +1, -1])
 @pytest.mark.parametrize("num", [
-    0.001, 1, 10
-])
+    0.001, 1, 10])
 def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
     with expectation:
-        assert Timedelta(str(sign*num)+redundant_unit, unit=unit) == Timedelta(sign*num, unit=unit)
+        assert Timedelta(str(sign * num) + redundant_unit, unit=unit) \
+               == Timedelta(sign * num, unit=unit)

From 23a9834e6033578a2c4a335151f8c4ac508df600 Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 12:03:44 -0300
Subject: [PATCH 03/22] Updated function signature in pxd file.

---
 pandas/_libs/tslibs/timedeltas.pxd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pxd b/pandas/_libs/tslibs/timedeltas.pxd
index eda4418902513..3ab70f55881b4 100644
--- a/pandas/_libs/tslibs/timedeltas.pxd
+++ b/pandas/_libs/tslibs/timedeltas.pxd
@@ -3,7 +3,7 @@
 from numpy cimport int64_t
 
 # Exposed for tslib, not intended for outside use.
-cdef parse_timedelta_string(object ts)
+cdef parse_timedelta_string(object ts, object specified_unit=None)
 cpdef int64_t cast_from_unit(object ts, object unit) except? -1
 cpdef int64_t delta_to_nanoseconds(delta) except? -1
 cpdef convert_to_timedelta64(object ts, object unit)

From d34140d89a06e915228e153a1c3bde30fc97d1b8 Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 16:06:50 -0300
Subject: [PATCH 04/22] Passing tests.

---
 pandas/_libs/tslibs/timedeltas.pxd            |  2 +-
 pandas/_libs/tslibs/timedeltas.pyx            | 23 +++++++++++++------
 .../scalar/timedelta/test_construction.py     | 10 +++-----
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pxd b/pandas/_libs/tslibs/timedeltas.pxd
index 3ab70f55881b4..dbdead1dba551 100644
--- a/pandas/_libs/tslibs/timedeltas.pxd
+++ b/pandas/_libs/tslibs/timedeltas.pxd
@@ -3,7 +3,7 @@
 from numpy cimport int64_t
 
 # Exposed for tslib, not intended for outside use.
-cdef parse_timedelta_string(object ts, object specified_unit=None)
+cdef parse_timedelta_string(object ts, specified_unit=*)
 cpdef int64_t cast_from_unit(object ts, object unit) except? -1
 cpdef int64_t delta_to_nanoseconds(delta) except? -1
 cpdef convert_to_timedelta64(object ts, object unit)
diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index cb0534cbb6d0d..91bfb2435835e 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -245,7 +245,7 @@ cdef inline _decode_if_necessary(object ts):
     return ts
 
 
-cdef inline parse_timedelta_string(object ts, object specified_unit=None):
+cdef inline parse_timedelta_string(object ts, specified_unit=None):
     """
     Parse a regular format timedelta string. Return an int64_t (in ns)
     or raise a ValueError on an invalid parse.
@@ -407,10 +407,7 @@ cdef inline parse_timedelta_string(object ts, object specified_unit=None):
         if have_value:
             raise ValueError("have leftover units")
         if len(number):
-            if specified_unit is None:
-                fallback_unit = 'ns'
-            else:
-                fallback_unit = specified_unit
+            fallback_unit = 'ns' if specified_unit is None else specified_unit
             r = timedelta_from_spec(number, frac, fallback_unit)
             result += timedelta_as_neg(r, neg)
 
@@ -1004,13 +1001,25 @@ class Timedelta(_Timedelta):
                                  "[weeks, days, hours, minutes, seconds, "
                                  "milliseconds, microseconds, nanoseconds]")
 
+
         if isinstance(value, Timedelta):
             value = value.value
         elif is_string_object(value):
-            if len(value) > 0 and value[0] == 'P':
+            # Check if it is just a number in a string
+            try:
+                value = int(value)
+            except (ValueError, TypeError):
+                try:
+                    value = float(value)
+                except (ValueError, TypeError):
+                    pass
+
+            if is_integer_object(value) or is_float_object(value):
+                value = convert_to_timedelta64(value, unit)
+            elif len(value) > 0 and value[0] == 'P':
                 value = parse_iso_format_string(value)
             else:
-                value = parse_timedelta_string(value)
+                value = parse_timedelta_string(value, unit)
             value = np.timedelta64(value)
         elif PyDelta_Check(value):
             value = convert_to_timedelta64(value, 'ns')
diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 451c8df4c39fb..47f255b68fddb 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -85,10 +85,6 @@ def test_construction():
     with pytest.raises(ValueError):
         Timedelta('10 days -1 h 1.5m 1s 3us')
 
-    # no units specified
-    with pytest.raises(ValueError):
-        Timedelta('3.1415')
-
     # invalid construction
     tm.assert_raises_regex(ValueError, "cannot construct a Timedelta",
                            lambda: Timedelta())
@@ -225,12 +221,12 @@ def __exit__(self, exc_type, exc_val, exc_tb):
     ("d", pytest.raises(ValueError)),
     ("us", pytest.raises(ValueError))])
 @pytest.mark.parametrize("unit", [
-   "d", "m", "s", "us"])
+    "d", "m", "s", "us"])
 @pytest.mark.parametrize("sign", [
-   +1, -1])
+    +1, -1])
 @pytest.mark.parametrize("num", [
     0.001, 1, 10])
 def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
     with expectation:
         assert Timedelta(str(sign * num) + redundant_unit, unit=unit) \
-               == Timedelta(sign * num, unit=unit)
+        == Timedelta(sign * num, unit=unit)

From a2d68e68cf2f1527ffb370ecaeb25731191a86ff Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 16:12:46 -0300
Subject: [PATCH 05/22] Fixed linting.

---
 pandas/tests/scalar/timedelta/test_construction.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 47f255b68fddb..2f6696a276ed7 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -228,5 +228,5 @@ def __exit__(self, exc_type, exc_val, exc_tb):
     0.001, 1, 10])
 def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
     with expectation:
-        assert Timedelta(str(sign * num) + redundant_unit, unit=unit) \
-        == Timedelta(sign * num, unit=unit)
+        assert Timedelta(str(sign * num) + redundant_unit, unit=unit)\
+            == Timedelta(sign * num, unit=unit)

From 521857ca384c8125c3f035b6d8d9ba42850a9d58 Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 17:24:23 -0300
Subject: [PATCH 06/22] Removed excess space LINT

---
 pandas/_libs/tslibs/timedeltas.pyx | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index 91bfb2435835e..cec07dbebdfa4 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -1001,7 +1001,6 @@ class Timedelta(_Timedelta):
                                  "[weeks, days, hours, minutes, seconds, "
                                  "milliseconds, microseconds, nanoseconds]")
 
-
         if isinstance(value, Timedelta):
             value = value.value
         elif is_string_object(value):

From d8b71279207bad4d49b8fe499e526bd9fb5b8193 Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Sat, 9 Jun 2018 16:42:38 -0300
Subject: [PATCH 07/22] Fixed long line.

---
 pandas/tests/scalar/timedelta/test_construction.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 2f6696a276ed7..79c742e97cc04 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -228,5 +228,6 @@ def __exit__(self, exc_type, exc_val, exc_tb):
     0.001, 1, 10])
 def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
     with expectation:
-        assert Timedelta(str(sign * num) + redundant_unit, unit=unit)\
-            == Timedelta(sign * num, unit=unit)
+        val = sign * num
+        val_str = str(val) + redundant_unit
+        assert Timedelta(val_str, unit=unit) == Timedelta(val, unit=unit)

From 0ddbcec95da918e909829d40a9407d746b144123 Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 11:39:11 -0300
Subject: [PATCH 08/22] Accepts integer/float string with units and raises when
 unit is ambiguous.

---
 .../scalar/timedelta/test_construction.py     | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 79c742e97cc04..0283b70350bf6 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -85,6 +85,10 @@ def test_construction():
     with pytest.raises(ValueError):
         Timedelta('10 days -1 h 1.5m 1s 3us')
 
+    # no units specified
+    with pytest.raises(ValueError):
+        Timedelta('3.1415')
+
     # invalid construction
     tm.assert_raises_regex(ValueError, "cannot construct a Timedelta",
                            lambda: Timedelta())
@@ -219,15 +223,17 @@ def __exit__(self, exc_type, exc_val, exc_tb):
 @pytest.mark.parametrize("redundant_unit, expectation", [
     ("", not_raises()),
     ("d", pytest.raises(ValueError)),
-    ("us", pytest.raises(ValueError))])
+    ("us", pytest.raises(ValueError)),
+])
 @pytest.mark.parametrize("unit", [
-    "d", "m", "s", "us"])
+   "d", "m", "s", "us"
+])
 @pytest.mark.parametrize("sign", [
-    +1, -1])
+   +1, -1
+])
 @pytest.mark.parametrize("num", [
-    0.001, 1, 10])
+    0.001, 1, 10
+])
 def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
     with expectation:
-        val = sign * num
-        val_str = str(val) + redundant_unit
-        assert Timedelta(val_str, unit=unit) == Timedelta(val, unit=unit)
+        assert Timedelta(str(sign*num)+redundant_unit, unit=unit) == Timedelta(sign*num, unit=unit)

From ce94192f4c063248456f6107e251377d3cca0821 Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 12:03:44 -0300
Subject: [PATCH 09/22] Updated function signature in pxd file.

---
 pandas/_libs/tslibs/timedeltas.pxd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pxd b/pandas/_libs/tslibs/timedeltas.pxd
index dbdead1dba551..3ab70f55881b4 100644
--- a/pandas/_libs/tslibs/timedeltas.pxd
+++ b/pandas/_libs/tslibs/timedeltas.pxd
@@ -3,7 +3,7 @@
 from numpy cimport int64_t
 
 # Exposed for tslib, not intended for outside use.
-cdef parse_timedelta_string(object ts, specified_unit=*)
+cdef parse_timedelta_string(object ts, object specified_unit=None)
 cpdef int64_t cast_from_unit(object ts, object unit) except? -1
 cpdef int64_t delta_to_nanoseconds(delta) except? -1
 cpdef convert_to_timedelta64(object ts, object unit)

From c5900924c4af327cec918ce6f4537c69929a8615 Mon Sep 17 00:00:00 2001
From: Victor <victor.maryama@typhoon-hil.com>
Date: Fri, 8 Jun 2018 16:06:50 -0300
Subject: [PATCH 10/22] Passing tests.

---
 pandas/_libs/tslibs/timedeltas.pxd            |  2 +-
 .../scalar/timedelta/test_construction.py     | 19 ++++++-------------
 2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pxd b/pandas/_libs/tslibs/timedeltas.pxd
index 3ab70f55881b4..dbdead1dba551 100644
--- a/pandas/_libs/tslibs/timedeltas.pxd
+++ b/pandas/_libs/tslibs/timedeltas.pxd
@@ -3,7 +3,7 @@
 from numpy cimport int64_t
 
 # Exposed for tslib, not intended for outside use.
-cdef parse_timedelta_string(object ts, object specified_unit=None)
+cdef parse_timedelta_string(object ts, specified_unit=*)
 cpdef int64_t cast_from_unit(object ts, object unit) except? -1
 cpdef int64_t delta_to_nanoseconds(delta) except? -1
 cpdef convert_to_timedelta64(object ts, object unit)
diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 0283b70350bf6..47f255b68fddb 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -85,10 +85,6 @@ def test_construction():
     with pytest.raises(ValueError):
         Timedelta('10 days -1 h 1.5m 1s 3us')
 
-    # no units specified
-    with pytest.raises(ValueError):
-        Timedelta('3.1415')
-
     # invalid construction
     tm.assert_raises_regex(ValueError, "cannot construct a Timedelta",
                            lambda: Timedelta())
@@ -223,17 +219,14 @@ def __exit__(self, exc_type, exc_val, exc_tb):
 @pytest.mark.parametrize("redundant_unit, expectation", [
     ("", not_raises()),
     ("d", pytest.raises(ValueError)),
-    ("us", pytest.raises(ValueError)),
-])
+    ("us", pytest.raises(ValueError))])
 @pytest.mark.parametrize("unit", [
-   "d", "m", "s", "us"
-])
+    "d", "m", "s", "us"])
 @pytest.mark.parametrize("sign", [
-   +1, -1
-])
+    +1, -1])
 @pytest.mark.parametrize("num", [
-    0.001, 1, 10
-])
+    0.001, 1, 10])
 def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
     with expectation:
-        assert Timedelta(str(sign*num)+redundant_unit, unit=unit) == Timedelta(sign*num, unit=unit)
+        assert Timedelta(str(sign * num) + redundant_unit, unit=unit) \
+        == Timedelta(sign * num, unit=unit)

From bb08fc403bdf29d7ce4006f0baf107aef75590c2 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 20:45:02 +0200
Subject: [PATCH 11/22] Moved whatsnew to 0.24.0.

---
 doc/source/whatsnew/v0.24.0.txt | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v0.24.0.txt b/doc/source/whatsnew/v0.24.0.txt
index b71edcf1f6f51..5bbdddaf60fbe 100644
--- a/doc/source/whatsnew/v0.24.0.txt
+++ b/doc/source/whatsnew/v0.24.0.txt
@@ -665,8 +665,7 @@ Timedelta
 - Bug in :class:`Index` with numeric dtype when multiplying or dividing an array with dtype ``timedelta64`` (:issue:`22390`)
 - Bug in :class:`TimedeltaIndex` incorrectly allowing indexing with ``Timestamp`` object (:issue:`20464`)
 - Fixed bug where subtracting :class:`Timedelta` from an object-dtyped array would raise ``TypeError`` (:issue:`21980`)
--
--
+- Bug in :class:`Timedelta`: where passing a string of a pure number would not take unit into account. Also raises for ambiguous/duplicate unit specification (:issue: `12136`)
 
 Timezones
 ^^^^^^^^^

From 2c46d7342ad8d00225a85148bdcfb8f32fd6f83c Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 20:45:53 +0200
Subject: [PATCH 12/22] Reverted parse_timedelta_string signature.

---
 pandas/_libs/tslibs/timedeltas.pxd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pxd b/pandas/_libs/tslibs/timedeltas.pxd
index dbdead1dba551..eda4418902513 100644
--- a/pandas/_libs/tslibs/timedeltas.pxd
+++ b/pandas/_libs/tslibs/timedeltas.pxd
@@ -3,7 +3,7 @@
 from numpy cimport int64_t
 
 # Exposed for tslib, not intended for outside use.
-cdef parse_timedelta_string(object ts, specified_unit=*)
+cdef parse_timedelta_string(object ts)
 cpdef int64_t cast_from_unit(object ts, object unit) except? -1
 cpdef int64_t delta_to_nanoseconds(delta) except? -1
 cpdef convert_to_timedelta64(object ts, object unit)

From 298a33cc7b8e65e5c2685940b2f50df88ebc0718 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 21:05:46 +0200
Subject: [PATCH 13/22] Checking float with units in Timedelta class.

---
 pandas/_libs/tslibs/timedeltas.pyx | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index cec07dbebdfa4..3d98701603047 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -969,7 +969,7 @@ class Timedelta(_Timedelta):
     ----------
     value : Timedelta, timedelta, np.timedelta64, string, or integer
     unit : string, {'ns', 'us', 'ms', 's', 'm', 'h', 'D'}, optional
-        Denote the unit of the input, if input is an integer. Default 'ns'.
+        Denote the unit of the input, if input is an integer/float. Default 'ns'.
     days, seconds, microseconds,
     milliseconds, minutes, hours, weeks : numeric, optional
         Values for construction in compat with datetime.timedelta.
@@ -1018,8 +1018,15 @@ class Timedelta(_Timedelta):
             elif len(value) > 0 and value[0] == 'P':
                 value = parse_iso_format_string(value)
             else:
-                value = parse_timedelta_string(value, unit)
-            value = np.timedelta64(value)
+                try:
+                    value = float(value)
+                except ValueError:
+                    value = parse_timedelta_string(value)
+                    value = np.timedelta64(value)
+                else:
+                    if unit is None:
+                        raise ValueError("Cannot convert float string without unit.")
+                    value = convert_to_timedelta64(value, unit)
         elif PyDelta_Check(value):
             value = convert_to_timedelta64(value, 'ns')
         elif is_timedelta64_object(value):

From 677a8f8c18eb7ef4d1f02668446ed4f7b2cb3429 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 21:08:44 +0200
Subject: [PATCH 14/22] Reverted test with exceptions for strings without unit.

---
 pandas/tests/scalar/timedelta/test_construction.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 47f255b68fddb..23dd6c3fbd697 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -85,6 +85,10 @@ def test_construction():
     with pytest.raises(ValueError):
         Timedelta('10 days -1 h 1.5m 1s 3us')
 
+    # no units specified
+    with pytest.raises(ValueError):
+        Timedelta('3.1415')
+
     # invalid construction
     tm.assert_raises_regex(ValueError, "cannot construct a Timedelta",
                            lambda: Timedelta())

From a371472a9e67c898c7cf79d70f0b968482062996 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 21:12:23 +0200
Subject: [PATCH 15/22] Useing null context managers from contextlib.

---
 .../tests/scalar/timedelta/test_construction.py  | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 23dd6c3fbd697..e7470bc2f0123 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -8,6 +8,12 @@
 import pandas.util.testing as tm
 from pandas import Timedelta
 
+import sys
+if sys.version_info >= (3, 3):
+    from contextlib import ExitStack as do_not_raise
+else:
+    from contextlib2 import ExitStack as do_not_raise
+
 
 def test_construction():
     expected = np.timedelta64(10, 'D').astype('m8[ns]').view('i8')
@@ -212,16 +218,8 @@ def test_td_constructor_value_error():
         Timedelta(nanoseconds='abc')
 
 
-class not_raises(object):
-    def __enter__(self):
-        pass
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        pass
-
-
 @pytest.mark.parametrize("redundant_unit, expectation", [
-    ("", not_raises()),
+    ("", do_not_raise()),
     ("d", pytest.raises(ValueError)),
     ("us", pytest.raises(ValueError))])
 @pytest.mark.parametrize("unit", [

From 46693244c4f67781b2c470d1e744027367bbcbb5 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 21:15:10 +0200
Subject: [PATCH 16/22] Added null context manager for parametrizing tests on
 exception raising.

---
 pandas/util/testing.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/pandas/util/testing.py b/pandas/util/testing.py
index 3db251e89842d..79949ad5a34ea 100644
--- a/pandas/util/testing.py
+++ b/pandas/util/testing.py
@@ -48,6 +48,14 @@
 from pandas._libs import testing as _testing
 from pandas.io.common import urlopen
 
+if sys.version_info >= (3, 3):
+    from contextlib import ExitStack as nullcontext
+else:
+    from contextlib2 import ExitStack as nullcontext
+
+
+do_not_raise = nullcontext()
+
 
 N = 30
 K = 4

From 93602aca48cbb6485d662803e19760ada8617486 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 21:15:32 +0200
Subject: [PATCH 17/22] Using null context manager from pandas.util.testing.

---
 pandas/tests/scalar/timedelta/test_construction.py | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index e7470bc2f0123..7ff869487003f 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -8,12 +8,6 @@
 import pandas.util.testing as tm
 from pandas import Timedelta
 
-import sys
-if sys.version_info >= (3, 3):
-    from contextlib import ExitStack as do_not_raise
-else:
-    from contextlib2 import ExitStack as do_not_raise
-
 
 def test_construction():
     expected = np.timedelta64(10, 'D').astype('m8[ns]').view('i8')
@@ -219,7 +213,7 @@ def test_td_constructor_value_error():
 
 
 @pytest.mark.parametrize("redundant_unit, expectation", [
-    ("", do_not_raise()),
+    ("", tm.do_not_raise),
     ("d", pytest.raises(ValueError)),
     ("us", pytest.raises(ValueError))])
 @pytest.mark.parametrize("unit", [

From 28ffc982ad0069c3ce08cc6fd9fe7f860f8c1b1a Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 21:35:35 +0200
Subject: [PATCH 18/22] Raise when defining units in string and constructor.

---
 pandas/_libs/tslibs/timedeltas.pyx | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index 3d98701603047..84e15b645c90a 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -1021,6 +1021,8 @@ class Timedelta(_Timedelta):
                 try:
                     value = float(value)
                 except ValueError:
+                    if unit is not None:
+                        raise ValueError("Unit cannot be defined for strings other than pure integer/floats.")
                     value = parse_timedelta_string(value)
                     value = np.timedelta64(value)
                 else:

From 654a0ea5ea7ebdffd4ebc715361f2d082137e8da Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Sun, 30 Sep 2018 21:36:07 +0200
Subject: [PATCH 19/22] Simplified and added to_timedelta to test.

---
 .../scalar/timedelta/test_construction.py     | 22 ++++++++-----------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index 7ff869487003f..d3800705e9895 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -212,17 +212,13 @@ def test_td_constructor_value_error():
         Timedelta(nanoseconds='abc')
 
 
-@pytest.mark.parametrize("redundant_unit, expectation", [
-    ("", tm.do_not_raise),
-    ("d", pytest.raises(ValueError)),
-    ("us", pytest.raises(ValueError))])
-@pytest.mark.parametrize("unit", [
-    "d", "m", "s", "us"])
-@pytest.mark.parametrize("sign", [
-    +1, -1])
-@pytest.mark.parametrize("num", [
-    0.001, 1, 10])
-def test_string_with_unit(num, sign, unit, redundant_unit, expectation):
+@pytest.mark.parametrize("str_unit, unit, expectation", [
+    ("", "s", tm.do_not_raise),
+    ("s", "s", pytest.raises(ValueError)),
+    ("", None, pytest.raises(ValueError)),
+    ("s", "d", pytest.raises(ValueError)),])
+def test_string_with_unit(str_unit, unit, expectation):
     with expectation:
-        assert Timedelta(str(sign * num) + redundant_unit, unit=unit) \
-        == Timedelta(sign * num, unit=unit)
+        val_str = "10{}".format(str_unit)
+        assert Timedelta(val_str, unit=unit) == Timedelta(10, unit=unit)
+        assert pd.to_timedelta(val_str, unit=unit) == Timedelta(10, unit=unit)

From f38b4cbfea75b385b2301b33b14f8d095a692a73 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Mon, 1 Oct 2018 01:11:46 +0200
Subject: [PATCH 20/22] Added debug info to exceptions.

---
 pandas/_libs/tslibs/timedeltas.pyx | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index 84e15b645c90a..6727a07b6e14c 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -1019,15 +1019,18 @@ class Timedelta(_Timedelta):
                 value = parse_iso_format_string(value)
             else:
                 try:
+                    orig_value = value
                     value = float(value)
                 except ValueError:
                     if unit is not None:
-                        raise ValueError("Unit cannot be defined for strings other than pure integer/floats.")
+                        raise ValueError("Unit cannot be defined for strings other than pure integer/floats."
+                        " Value: {} Unit: {}".format(value, unit))
                     value = parse_timedelta_string(value)
                     value = np.timedelta64(value)
                 else:
                     if unit is None:
-                        raise ValueError("Cannot convert float string without unit.")
+                        raise ValueError("Cannot convert float string without unit."
+                        " Value: {} Type: {}".format(orig_value, type(orig_value)))
                     value = convert_to_timedelta64(value, unit)
         elif PyDelta_Check(value):
             value = convert_to_timedelta64(value, 'ns')

From e3226305ece191c506c7a1afc97b50609b3d7b62 Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Mon, 1 Oct 2018 01:12:14 +0200
Subject: [PATCH 21/22] Null context manager implementation.

---
 pandas/util/testing.py | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/pandas/util/testing.py b/pandas/util/testing.py
index 79949ad5a34ea..a03827a361a8e 100644
--- a/pandas/util/testing.py
+++ b/pandas/util/testing.py
@@ -48,13 +48,17 @@
 from pandas._libs import testing as _testing
 from pandas.io.common import urlopen
 
-if sys.version_info >= (3, 3):
-    from contextlib import ExitStack as nullcontext
-else:
-    from contextlib2 import ExitStack as nullcontext
+
+class NullContextManager(object):
+    def __init__(self, dummy_resource=None):
+        self.dummy_resource = dummy_resource
+    def __enter__(self):
+        return self.dummy_resource
+    def __exit__(self, *args):
+        pass
 
 
-do_not_raise = nullcontext()
+do_not_raise = NullContextManager()
 
 
 N = 30

From 85f04c9c44cc20b5dace8fd0301858fcb9bc57ce Mon Sep 17 00:00:00 2001
From: victor <victor.maryama@typhoon-hil.com>
Date: Mon, 1 Oct 2018 01:48:22 +0200
Subject: [PATCH 22/22] Updated test.

---
 pandas/tests/scalar/timedelta/test_construction.py | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/scalar/timedelta/test_construction.py b/pandas/tests/scalar/timedelta/test_construction.py
index d3800705e9895..a167ceed7059a 100644
--- a/pandas/tests/scalar/timedelta/test_construction.py
+++ b/pandas/tests/scalar/timedelta/test_construction.py
@@ -89,6 +89,9 @@ def test_construction():
     with pytest.raises(ValueError):
         Timedelta('3.1415')
 
+    with pytest.raises(ValueError):
+        Timedelta('2000')
+
     # invalid construction
     tm.assert_raises_regex(ValueError, "cannot construct a Timedelta",
                            lambda: Timedelta())
@@ -213,10 +216,11 @@ def test_td_constructor_value_error():
 
 
 @pytest.mark.parametrize("str_unit, unit, expectation", [
-    ("", "s", tm.do_not_raise),
-    ("s", "s", pytest.raises(ValueError)),
-    ("", None, pytest.raises(ValueError)),
-    ("s", "d", pytest.raises(ValueError)),])
+    ("", "s", tm.do_not_raise),              # Expected case
+    ("s", "s", pytest.raises(ValueError)),   # Units doubly defined
+    ("s", "d", pytest.raises(ValueError)),
+    ("", None, pytest.raises(ValueError)),   # No units
+])
 def test_string_with_unit(str_unit, unit, expectation):
     with expectation:
         val_str = "10{}".format(str_unit)