merge main, test invalid method

narwhals/expr.py

@@ -2528,7 +2528,10 @@ def rank(
 
         supported_rank_methods = {"average", "min", "max", "dense", "ordinal"}
         if method not in supported_rank_methods:
-            msg = f"Ranking method must be one of {supported_rank_methods}. Found '{method}'"
+            msg = (
+                "Ranking method must be one of {'average', 'min', 'max', 'dense', 'ordinal'}. "
+                f"Found '{method}'"
+            )
             raise ValueError(msg)
 
         return self.__class__(

narwhals/series.py

@@ -2731,7 +2731,10 @@ def rank(
         """
         supported_rank_methods = {"average", "min", "max", "dense", "ordinal"}
         if method not in supported_rank_methods:
-            msg = f"Ranking method must be one of {supported_rank_methods}. Found '{method}'"
+            msg = (
+                "Ranking method must be one of {'average', 'min', 'max', 'dense', 'ordinal'}. "
+                f"Found '{method}'"
+            )
             raise ValueError(msg)
 
         return self._from_compliant_series(

tests/expr_and_series/rank_test.py

@@ -101,3 +101,19 @@ def test_rank_expr_in_over_context(
     result = df.select(nw.col("a").rank(method=method).over("b"))
     expected_data = {"a": expected_over[method]}
     assert_equal_data(result, expected_data)
+
+
+def test_invalid_method_raise(constructor: Constructor) -> None:
+    method = "invalid_method_name"
+    df = nw.from_native(constructor(data_float))
+
+    msg = (
+        "Ranking method must be one of {'average', 'min', 'max', 'dense', 'ordinal'}. "
+        f"Found '{method}'"
+    )
+
+    with pytest.raises(ValueError, match=msg):
+        df.select(nw.col("a").rank(method=method))  # type: ignore[arg-type]
+
+    with pytest.raises(ValueError, match=msg):
+        df.lazy().collect()["a"].rank(method=method)  # type: ignore[arg-type]