add match message for pytest.raises()

pandas/tests/groupby/test_categorical.py

@@ -609,7 +609,8 @@ def test_bins_unequal_len():
     bins = pd.cut(series.dropna().values, 4)
 
     # len(bins) != len(series) here
-    with pytest.raises(ValueError):
+    msg = r"Length of grouper \(8\) and axis \(10\) must be same length"
+    with pytest.raises(ValueError, match=msg):
         series.groupby(bins).mean()
 
 

pandas/tests/indexes/common.py

@@ -349,7 +349,8 @@ def test_take(self, indices):
 
         if not isinstance(indices, (DatetimeIndex, PeriodIndex, TimedeltaIndex)):
             # GH 10791
-            with pytest.raises(AttributeError):
+            msg = r"'(.*Index)' object has no attribute 'freq'"
+            with pytest.raises(AttributeError, match=msg):
                 indices.freq
 
     def test_take_invalid_kwargs(self):
@@ -537,9 +538,10 @@ def test_delete_base(self, indices):
         assert result.equals(expected)
         assert result.name == expected.name
 
-        with pytest.raises((IndexError, ValueError)):
-            # either depending on numpy version
-            indices.delete(len(indices))
+        length = len(indices)
+        msg = f"index {length} is out of bounds for axis 0 with size {length}"
+        with pytest.raises(IndexError, match=msg):
+            indices.delete(length)
 
     def test_equals(self, indices):
         if isinstance(indices, IntervalIndex):
@@ -787,13 +789,14 @@ def test_putmask_with_wrong_mask(self):
         # GH18368
         index = self.create_index()
 
-        with pytest.raises(ValueError):
+        msg = "putmask: mask and data must be the same size"
+        with pytest.raises(ValueError, match=msg):
             index.putmask(np.ones(len(index) + 1, np.bool), 1)
 
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match=msg):
             index.putmask(np.ones(len(index) - 1, np.bool), 1)
 
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match=msg):
             index.putmask("foo", 1)
 
     @pytest.mark.parametrize("copy", [True, False])
@@ -861,10 +864,21 @@ def test_getitem_2d_deprecated(self):
 
     def test_contains_requires_hashable_raises(self):
         idx = self.create_index()
-        with pytest.raises(TypeError, match="unhashable type"):
+
+        msg = "unhashable type: 'list'"
+        with pytest.raises(TypeError, match=msg):
             [] in idx
 
-        with pytest.raises(TypeError):
+        msg = "|".join(
+            [
+                r"unhashable type: 'dict'",
+                r"must be real number, not dict",
+                r"an integer is required",
+                r"\{\}",
+                r"pandas\._libs\.interval\.IntervalTree' is not iterable",
+            ]
+        )
+        with pytest.raises(TypeError, match=msg):
             {} in idx._engine
 
     def test_copy_copies_cache(self):

pandas/tests/indexes/datetimelike.py

@@ -11,14 +11,15 @@
 class DatetimeLike(Base):
     def test_argmax_axis_invalid(self):
         # GH#23081
+        msg = r"`axis` must be fewer than the number of dimensions \(1\)"
         rng = self.create_index()
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match=msg):
             rng.argmax(axis=1)
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match=msg):
             rng.argmin(axis=2)
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match=msg):
             rng.min(axis=-2)
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match=msg):
             rng.max(axis=-3)
 
     def test_can_hold_identifiers(self):

pandas/tests/indexes/multi/test_compat.py

@@ -53,7 +53,11 @@ def test_boolean_context_compat2():
     i2 = MultiIndex.from_tuples([("A", 1), ("A", 3)])
     common = i1.intersection(i2)
 
-    with pytest.raises(ValueError):
+    msg = (
+        r"The truth value of a MultiIndex is ambiguous\. "
+        r"Use a\.empty, a\.bool\(\), a\.item\(\), a\.any\(\) or a\.all\(\)\."
+    )
+    with pytest.raises(ValueError, match=msg):
         bool(common)
 
 

pandas/tests/indexes/multi/test_reshape.py

@@ -175,6 +175,6 @@ def test_delete_base(idx):
     assert result.equals(expected)
     assert result.name == expected.name
 
-    with pytest.raises((IndexError, ValueError)):
-        # Exception raised depends on NumPy version.
+    msg = "index 6 is out of bounds for axis 0 with size 6"
+    with pytest.raises(IndexError, match=msg):
         idx.delete(len(idx))

pandas/tests/indexes/multi/test_sorting.py

@@ -105,7 +105,11 @@ def test_unsortedindex():
     expected = df.iloc[0]
     tm.assert_series_equal(result, expected)
 
-    with pytest.raises(UnsortedIndexError):
+    msg = (
+        "MultiIndex slicing requires the index to be lexsorted: "
+        r"slicing on levels \[1\], lexsort depth 0"
+    )
+    with pytest.raises(UnsortedIndexError, match=msg):
         df.loc(axis=0)["z", slice("a")]
     df.sort_index(inplace=True)
     assert len(df.loc(axis=0)["z", :]) == 2
@@ -124,7 +128,8 @@ def test_unsortedindex_doc_examples():
     with tm.assert_produces_warning(PerformanceWarning):
         dfm.loc[(1, "z")]
 
-    with pytest.raises(UnsortedIndexError):
+    msg = r"Key length \(2\) was greater than MultiIndex lexsort depth \(1\)"
+    with pytest.raises(UnsortedIndexError, match=msg):
         dfm.loc[(0, "y"):(1, "z")]
 
     assert not dfm.index.is_lexsorted()