add test dupe check up front

Author: Emyrk

provider/formtype_test.go

@@ -240,13 +240,13 @@ func TestValidateFormType(t *testing.T) {
 		for _, c := range cases {
 			t.Run(c.name, func(t *testing.T) {
 				t.Parallel()
-
-				formTypesChecked[c.config.String()] = struct{}{}
-				formTypeTest(t, c)
 				if _, ok := formTypesChecked[c.config.String()]; ok {
 					t.Log("Duplicated form type check, delete this extra test case")
 					t.Fatalf("form type %q already checked", c.config.String())
 				}
+
+				formTypesChecked[c.config.String()] = struct{}{}
+				formTypeTest(t, c)
 			})
 		}
 	})