Check error message for raised exception

pandas/core/arrays/period.py

@@ -166,7 +166,8 @@ def __init__(self, values, freq=None, dtype=None, copy=False):
     @classmethod
     def _simple_new(cls, values: np.ndarray, freq=None, **kwargs) -> "PeriodArray":
         # alias for PeriodArray.__init__
-        assert isinstance(values, np.ndarray) and values.dtype == "i8"
+        assertion_msg = "Should be numpy array of type i8"
+        assert isinstance(values, np.ndarray) and values.dtype == "i8", assertion_msg
         return cls(values, freq=freq, **kwargs)
 
     @classmethod

pandas/tests/indexes/categorical/test_category.py

@@ -192,7 +192,7 @@ def test_delete(self):
         expected = CategoricalIndex(list("aabbc"), categories=categories)
         tm.assert_index_equal(result, expected, exact=True)
 
-        with pytest.raises((IndexError, ValueError)):
+        with tm.external_error_raised((IndexError, ValueError)):
             # Either depending on NumPy version
             ci.delete(10)
 

pandas/tests/indexes/period/test_constructors.py

@@ -327,7 +327,8 @@ def test_constructor_simple_new(self):
         result = idx._simple_new(idx._data, name="p")
         tm.assert_index_equal(result, idx)
 
-        with pytest.raises(AssertionError):
+        msg = "Should be numpy array of type i8"
+        with pytest.raises(AssertionError, match=msg):
             # Need ndarray, not Int64Index
             type(idx._data)._simple_new(idx.astype("i8"), freq=idx.freq)
 

pandas/tests/indexes/period/test_join.py

@@ -39,5 +39,6 @@ def test_join_does_not_recur(self):
     def test_join_mismatched_freq_raises(self):
         index = period_range("1/1/2000", "1/20/2000", freq="D")
         index3 = period_range("1/1/2000", "1/20/2000", freq="2D")
-        with pytest.raises(IncompatibleFrequency):
+        msg = r".*Input has different freq=2D from PeriodIndex\(freq=D\)"
+        with pytest.raises(IncompatibleFrequency, match=msg):
             index.join(index3)

pandas/tests/indexes/period/test_partial_slicing.py

@@ -59,6 +59,7 @@ def test_range_slice_day(self):
         didx = pd.date_range(start="2013/01/01", freq="D", periods=400)
         pidx = period_range(start="2013/01/01", freq="D", periods=400)
 
+        msg = "slice indices must be integers or None or have an __index__ method"
         for idx in [didx, pidx]:
             # slices against index should raise IndexError
             values = [
@@ -69,7 +70,7 @@ def test_range_slice_day(self):
                 "2013/02/01 09:00",
             ]
             for v in values:
-                with pytest.raises(TypeError):
+                with pytest.raises(TypeError, match=msg):
                     idx[v:]
 
             s = Series(np.random.rand(len(idx)), index=idx)
@@ -81,13 +82,14 @@ def test_range_slice_day(self):
 
             invalid = ["2013/02/01 9H", "2013/02/01 09:00"]
             for v in invalid:
-                with pytest.raises(TypeError):
+                with pytest.raises(TypeError, match=msg):
                     idx[v:]
 
     def test_range_slice_seconds(self):
         # GH#6716
         didx = pd.date_range(start="2013/01/01 09:00:00", freq="S", periods=4000)
         pidx = period_range(start="2013/01/01 09:00:00", freq="S", periods=4000)
+        msg = "slice indices must be integers or None or have an __index__ method"
 
         for idx in [didx, pidx]:
             # slices against index should raise IndexError
@@ -99,7 +101,7 @@ def test_range_slice_seconds(self):
                 "2013/02/01 09:00",
             ]
             for v in values:
-                with pytest.raises(TypeError):
+                with pytest.raises(TypeError, match=msg):
                     idx[v:]
 
             s = Series(np.random.rand(len(idx)), index=idx)

pandas/tests/indexes/period/test_setops.py

@@ -148,7 +148,8 @@ def test_union_misc(self, sort):
         # raise if different frequencies
         index = period_range("1/1/2000", "1/20/2000", freq="D")
         index2 = period_range("1/1/2000", "1/20/2000", freq="W-WED")
-        with pytest.raises(IncompatibleFrequency):
+        msg = r"Input has different freq=W-WED from PeriodIndex\(freq=D\)"
+        with pytest.raises(IncompatibleFrequency, match=msg):
             index.union(index2, sort=sort)
 
     # TODO: belongs elsewhere
@@ -180,11 +181,13 @@ def test_intersection(self, sort):
         # raise if different frequencies
         index = period_range("1/1/2000", "1/20/2000", freq="D")
         index2 = period_range("1/1/2000", "1/20/2000", freq="W-WED")
-        with pytest.raises(IncompatibleFrequency):
+        msg = r"Input has different freq=W-WED from PeriodIndex\(freq=D\)"
+        with pytest.raises(IncompatibleFrequency, match=msg):
             index.intersection(index2, sort=sort)
 
         index3 = period_range("1/1/2000", "1/20/2000", freq="2D")
-        with pytest.raises(IncompatibleFrequency):
+        msg = r"Input has different freq=2D from PeriodIndex\(freq=D\)"
+        with pytest.raises(IncompatibleFrequency, match=msg):
             index.intersection(index3, sort=sort)
 
     def test_intersection_cases(self, sort):

pandas/tests/indexes/timedeltas/test_delete.py

@@ -1,5 +1,3 @@
-import pytest
-
 from pandas import TimedeltaIndex, timedelta_range
 import pandas._testing as tm
 
@@ -30,7 +28,7 @@ def test_delete(self):
             assert result.name == expected.name
             assert result.freq == expected.freq
 
-        with pytest.raises((IndexError, ValueError)):
+        with tm.external_error_raised((IndexError, ValueError)):
             # either depending on numpy version
             idx.delete(5)