Move test into right module.

Author: tv3141

pandas/tests/groupby/test_counting.py

@@ -222,16 +222,6 @@ def test_count_with_only_nans_in_first_group(self):
         expected = Series([], index=mi, dtype=np.int64, name="C")
         tm.assert_series_equal(result, expected, check_index_type=False)
 
-    def test_count_groupby_index_with_nan_in_index(self):
-        # https://github.com/pandas-dev/pandas/issues/21824
-        df = DataFrame({"Person": ["John", "Myla", None, "John", "Myla"],
-                        "Age": [24., 5, 21., 33, 26],
-                        "Single": [False, True, True, True, False]})
-
-        res = df.set_index(["Person", "Single"]).count(level="Person")
-        expected = DataFrame(index=Index(["John", "Myla"], name="Person"),
-                             data={"Age": [2, 2]})
-
     def test_count_groupby_column_with_nan_in_groupby_column(self):
         # https://github.com/pandas-dev/pandas/issues/32841
         df = DataFrame({"A": [1, 1, 1, 1, 1], "B": [5, 4, np.NaN, 3, 0]})

pandas/tests/test_multilevel.py

@@ -248,6 +248,17 @@ def _check_counts(frame, axis=0):
         result = self.frame.count(level=0, numeric_only=True)
         tm.assert_index_equal(result.columns, Index(list("ABC"), name="exp"))
 
+    def test_count_index_with_nan(self):
+        # https://github.com/pandas-dev/pandas/issues/21824
+        df = DataFrame({"Person": ["John", "Myla", None, "John", "Myla"],
+                        "Age": [24., 5, 21., 33, 26],
+                        "Single": [False, True, True, True, False]})
+
+        res = df.set_index(["Person", "Single"]).count(level="Person")
+        expected = DataFrame(index=Index(["John", "Myla"], name="Person"),
+                             data={"Age": [2, 2]})
+
+
     def test_count_level_series(self):
         index = MultiIndex(
             levels=[["foo", "bar", "baz"], ["one", "two", "three", "four"]],