TST: add test_join_multiindex_dates (pandas-dev#46660)

pandas/tests/frame/methods/test_join.py

@@ -345,6 +345,26 @@ def test_join_multiindex_leftright(self):
         tm.assert_frame_equal(df1.join(df2, how="right"), exp)
         tm.assert_frame_equal(df2.join(df1, how="left"), exp[["value2", "value1"]])
 
+    def test_join_multiindex_dates(self):
+        # GH 33692
+        date = pd.Timestamp(2000, 1, 1).date()
+
+        df1_index = MultiIndex.from_tuples([(0, date)], names=["index_0", "date"])
+        df1 = DataFrame({"col1": [0]}, index=df1_index)
+        df2_index = MultiIndex.from_tuples([(0, date)], names=["index_0", "date"])
+        df2 = DataFrame({"col2": [0]}, index=df2_index)
+        df3_index = MultiIndex.from_tuples([(0, date)], names=["index_0", "date"])
+        df3 = DataFrame({"col3": [0]}, index=df3_index)
+
+        result = df1.join([df2, df3])
+
+        expected_index = MultiIndex.from_tuples([(0, date)], names=["index_0", "date"])
+        expected = DataFrame(
+            {"col1": [0], "col2": [0], "col3": [0]}, index=expected_index
+        )
+
+        tm.assert_equal(result, expected)
+
     def test_merge_join_different_levels(self):
         # GH#9455