TST: Assert msg with pytest raises in pandas/tests/extension/base

pandas/tests/extension/base/getitem.py

@@ -160,11 +160,12 @@ def test_getitem_mask(self, data):
 
     def test_getitem_mask_raises(self, data):
         mask = np.array([True, False])
-        with pytest.raises(IndexError):
+        msg = f"Boolean index has wrong length: 2 instead of {len(data)}"
+        with pytest.raises(IndexError, match=msg):
             data[mask]
 
         mask = pd.array(mask, dtype="boolean")
-        with pytest.raises(IndexError):
+        with pytest.raises(IndexError, match=msg):
             data[mask]
 
     def test_getitem_boolean_array_mask(self, data):
@@ -305,7 +306,17 @@ def test_take_empty(self, data, na_value, na_cmp):
         result = empty.take([-1], allow_fill=True)
         assert na_cmp(result[0], na_value)
 
-        with pytest.raises(IndexError):
+        if empty.dtype.name == "arrow_string":
+            msg = "Index -1 out of bounds"
+        elif empty.dtype.name == "json":
+            msg = (
+                "Index is out of bounds or cannot do a non-empty take "
+                "from an empty array."
+            )
+        else:
+            msg = "cannot do a non-empty take from an empty axes."
+
+        with pytest.raises(IndexError, match=msg):
             empty.take([-1])
 
         with pytest.raises(IndexError, match="cannot do a non-empty take"):
@@ -330,13 +341,31 @@ def test_take_non_na_fill_value(self, data_missing):
         self.assert_extension_array_equal(result, expected)
 
     def test_take_pandas_style_negative_raises(self, data, na_value):
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match=""):
             data.take([0, -2], fill_value=na_value, allow_fill=True)
 
     @pytest.mark.parametrize("allow_fill", [True, False])
     def test_take_out_of_bounds_raises(self, data, allow_fill):
         arr = data[:3]
-        with pytest.raises(IndexError):
+        if (arr.dtype.name == "arrow_string") | ("Sparse" in arr.dtype.name):
+            msg = "out of bounds value in 'indices'."
+        elif arr.dtype.name == "json":
+            msg = (
+                "Index is out of bounds or cannot do a non-empty take "
+                "from an empty array."
+            )
+        else:
+            if allow_fill:
+                msg = "indices are out-of-bounds"
+            else:
+                if ("numpy" not in str(type(arr))) | (
+                    arr.dtype.name not in ["string"]
+                ):
+                    msg = "index 3 is out of bounds for axis 0 with size 3"
+                else:
+                    msg = "index 3 is out of bounds for size 3"
+
+        with pytest.raises(IndexError, match=msg):
             arr.take(np.asarray([0, 3]), allow_fill=allow_fill)
 
     def test_take_series(self, data):

pandas/tests/extension/base/reduce.py

@@ -1,3 +1,4 @@
+import re
 import warnings
 
 import pytest
@@ -8,6 +9,46 @@
 from .base import BaseExtensionTests
 
 
+def generate_error_message(dtype, op_name):
+    """
+    Generate an error message returned by the following
+
+        getattr(s, op_name)(skipna=skipna)
+
+    where `s` is an object with datatype `dtype`, `op_name` is an operation
+    to be performed on `s`, and `skipna` is a boolean flag.
+
+    Parameters
+    ----------
+    dtype : str
+        Datatype of the object `s`
+    op_name : str
+        Name of operation to perform on `s`
+
+    Returns
+    -------
+    str
+        Error message caused by performing the operation
+    """
+    if dtype == "category":
+        if op_name in ["min", "max"]:
+            return re.escape(
+                f"Categorical is not ordered for operation {op_name}\n"
+                "you can use .as_ordered() to change the Categorical to an "
+                "ordered one\n"
+            )
+        else:
+            return f"'Categorical' does not implement reduction '{op_name}'"
+    elif dtype in ["string", "arrow_string"]:
+        return f"Cannot perform reduction '{op_name}' with string dtype"
+    elif dtype == "interval":
+        return rf"cannot perform {op_name} with type interval\[float64\]"
+    elif dtype == "json":
+        return f"cannot perform {op_name} with type json"
+    elif dtype == "arrow_bool":
+        return ""
+
+
 class BaseReduceTests(BaseExtensionTests):
     """
     Reduction specific tests. Generally these only
@@ -28,15 +69,19 @@ def test_reduce_series_numeric(self, data, all_numeric_reductions, skipna):
         op_name = all_numeric_reductions
         s = pd.Series(data)
 
-        with pytest.raises(TypeError):
+        msg = generate_error_message(s.dtype.name, op_name)
+
+        with pytest.raises(TypeError, match=msg):
             getattr(s, op_name)(skipna=skipna)
 
     @pytest.mark.parametrize("skipna", [True, False])
     def test_reduce_series_boolean(self, data, all_boolean_reductions, skipna):
         op_name = all_boolean_reductions
         s = pd.Series(data)
 
-        with pytest.raises(TypeError):
+        msg = generate_error_message(s.dtype.name, op_name)
+
+        with pytest.raises(TypeError, match=msg):
             getattr(s, op_name)(skipna=skipna)