Added message to mask deprec test

Author: ShreyDixit

pandas/tests/frame/indexing/test_mask.py

@@ -92,14 +92,19 @@ def test_mask_dtype_bool_conversion(self):
 
     def test_mask_pos_args_deprecation(self):
         # https://github.com/pandas-dev/pandas/issues/41485
-        df = DataFrame(np.random.randn(5, 5))
-        cond = df > 0
-        other = DataFrame(np.random.randn(5, 3))
+        df = DataFrame({"a": range(5)})
+
+        expected = DataFrame({"a": [-1, 1, -1, 3, -1]})
+        cond = df % 2 == 0
+
+        msg = (
+            r"In a future version of pandas all arguments of NDFrame.mask except for "
+            r"the arguments 'cond' and 'other' will be keyword-only"
+        )
 
-        with tm.assert_produces_warning(FutureWarning):
-            result = df.mask(cond, other, False)
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = df.mask(cond, -1, False)
 
-        expected = df.mask(cond, other=other, inplace=False)
         tm.assert_frame_equal(result, expected)
 
 

pandas/tests/series/indexing/test_mask.py

@@ -90,11 +90,16 @@ def test_mask_stringdtype():
 
 def test_mask_pos_args_deprecation():
     # https://github.com/pandas-dev/pandas/issues/41485
-    s = Series(np.random.randn(6))
-    cond = s > 0
+    s = Series(range(5))
+    expected = Series([-1, 1, -1, 3, -1])
+    cond = s % 2 == 0
+
+    msg = (
+        r"In a future version of pandas all arguments of NDFrame.mask except for "
+        r"the arguments 'cond' and 'other' will be keyword-only"
+    )
 
-    with tm.assert_produces_warning(FutureWarning):
-        result = s.mask(cond, np.nan, False)
+    with tm.assert_produces_warning(FutureWarning, match=msg):
+        result = s.mask(cond, -1, False)
 
-    expected = s.mask(cond, other=np.nan, inplace=False)
     tm.assert_series_equal(result, expected)