update slow test

Author: jbrockmendel

pandas/tests/frame/methods/test_to_csv.py

@@ -359,7 +359,7 @@ def test_to_csv_nrows(self, nrows, temp_file):
             columns=Index(list("abcd"), dtype=object),
         )
         result, expected = self._return_result_expected(df, 1000, temp_file, "dt", "s")
-        expected.index = expected.index.astype("M8[ns]")
+        expected.index = expected.index.astype("M8[us]")
         tm.assert_frame_equal(result, expected, check_names=False)
 
     @pytest.mark.slow
@@ -390,9 +390,13 @@ def test_to_csv_idx_types(self, nrows, r_idx_type, c_idx_type, ncols, temp_file)
             r_idx_type,
             c_idx_type,
         )
-        if r_idx_type in ["dt", "p"]:
+        if r_idx_type == "dt":
+            expected.index = expected.index.astype("M8[us]")
+        elif r_idx_type == "p":
             expected.index = expected.index.astype("M8[ns]")
-        if c_idx_type in ["dt", "p"]:
+        if c_idx_type == "dt":
+            expected.columns = expected.columns.astype("M8[us]")
+        elif c_idx_type == "p":
             expected.columns = expected.columns.astype("M8[ns]")
         tm.assert_frame_equal(result, expected, check_names=False)