Use pytest fixtures & parametrize for tests

pandas/tests/reshape/merge/test_merge_ordered.py

@@ -212,23 +212,10 @@ def test_elements_not_in_by_but_in_df(self):
         with pytest.raises(KeyError, match=msg):
             merge_ordered(left, right, on="E", left_by=["G", "h"])
 
-    def test_ffill_validate_fill_method(self):
+    @pytest.mark.parametrize("invalid_method", ["linear", "carrot"])
+    def test_ffill_validate_fill_method(self, left, right, invalid_method):
         # GH 55884
-        df1 = DataFrame({"key": ["a", "c", "e"], "lvalue": [1, 2, 3]})
-        df2 = DataFrame({"key": ["b", "c", "d", "f"], "rvalue": [4, 5, 6, 7]})
-
-        for valid_method in ["ffill", None]:
-            try:
-                merge_ordered(df1, df2, on="key", fill_method=valid_method)
-            except Exception:
-                pytest.fail(f"Unexpected error with valid fill_method: {valid_method}")
-
-        for invalid_method in ["linear", "carrot"]:
-            with pytest.raises(
-                ValueError,
-                match=re.escape(
-                    "fill_method must be one of ['ffill']. "
-                    f"Got '{invalid_method}' instead."
-                ),
-            ):
-                merge_ordered(df1, df2, on="key", fill_method=invalid_method)
+        with pytest.raises(
+            ValueError, match=re.escape("fill_method must be 'ffill' or None")
+        ):
+            merge_ordered(left, right, on="key", fill_method=invalid_method)