bugfix test_iloc_mask test

Author: arthurlw

pandas/tests/indexing/test_iloc.py

@@ -735,8 +735,9 @@ def test_iloc_mask(self):
 
         mask.index = range(len(mask))
         result = df.iloc[mask]
-        expected = df.iloc[[0, 2, 4]]
-        tm.assert_frame_equal(result, expected)
+        msg = "Unalignable boolean Series provided as indexer"
+        with pytest.raises(IndexingError, match=msg):
+            df.iloc[mask]
 
         # ndarray ok
         result = df.iloc[np.array([True] * len(mask), dtype=bool)]
@@ -754,21 +755,20 @@ def test_iloc_mask(self):
             (None, ".iloc"): "0b1100",
             ("index", ""): "0b11",
             ("index", ".loc"): "0b11",
-            ("index", ".iloc"): "0b11",
-            ("locs", ""): "Unalignable boolean Series provided as indexer "
-            "(index of the boolean Series and of the indexed "
-            "object do not match).",
-            ("locs", ".loc"): "Unalignable boolean Series provided as indexer "
-            "(index of the boolean Series and of the "
-            "indexed object do not match).",
-            ("locs", ".iloc"): "0b1",
+            (
+                "index",
+                ".iloc",
+            ): "iLocation based boolean indexing cannot use an indexable as a mask",
+            ("locs", ""): "Unalignable boolean Series provided as indexer",
+            ("locs", ".loc"): "Unalignable boolean Series provided as indexer",
+            ("locs", ".iloc"): "Unalignable boolean Series provided as indexer",
         }
 
         # UserWarnings from reindex of a boolean mask
         for idx in [None, "index", "locs"]:
             mask = (df.nums > 2).values
             if idx:
-                mask_index = getattr(df, idx)[::-1]
+                mask_index = getattr(df, idx if idx == "index" else "locs")[::-1]
                 mask = Series(mask, list(mask_index))
             for method in ["", ".loc", ".iloc"]:
                 try:
@@ -787,11 +787,19 @@ def test_iloc_mask(self):
                     idx,
                     method,
                 )
-                r = expected.get(key)
-                if r != answer:
-                    raise AssertionError(
-                        f"[{key}] does not match [{answer}], received [{r}]"
+                expected_result = expected.get(key)
+
+                # Fix the assertion to check for substring match
+                if (
+                    idx is None or (idx == "index" and method != ".iloc")
+                ) and "0b" in expected_result:
+                    # For successful numeric results, exact match is needed
+                    assert expected_result == answer, (
+                        f"[{key}] does not match [{answer}]"
                     )
+                else:
+                    # For error messages, substring match is sufficient
+                    assert expected_result in answer, f"[{key}] not found in [{answer}]"
 
     def test_iloc_non_unique_indexing(self):
         # GH 4017, non-unique indexing (on the axis)