Update test_setitem and test_slice with modified error message

Author: hasanrashid

pandas/tests/frame/indexing/test_setitem.py

@@ -1098,7 +1098,7 @@ def test_setitem_loc_empty_indexer_raises_with_non_empty_value(self, box):
             indexer = box([], dtype="object")
         else:
             indexer = box([])
-        msg = "Must have equal len keys and value when setting with an iterable"
+        msg = "Length mismatch when setting Dataframe with an iterable"
         with pytest.raises(ValueError, match=msg):
             df.loc[indexer, ["b"]] = [1]
 

pandas/tests/indexing/multiindex/test_slice.py

@@ -660,7 +660,7 @@ def test_per_axis_per_level_setitem(self):
                 [[100], [100, 100]], dtype="int64"
             )
 
-        msg = "Must have equal len keys and value when setting with an iterable"
+        msg = "Length mismatch when setting Dataframe with an iterable"
         with pytest.raises(ValueError, match=msg):
             df.loc[(slice(None), 1), (slice(None), ["foo"])] = np.array(
                 [100, 100, 100, 100], dtype="int64"