feat(openapi): default graphql path for playground specs

Co-Authored-By: Virgil <virgil@lethean.io>

openapi.go

@@ -191,7 +191,11 @@ func (sb *SpecBuilder) buildPaths(groups []preparedRouteGroup) map[string]any {
 		},
 	}
 
-	if graphqlPath := strings.TrimSpace(sb.GraphQLPath); graphqlPath != "" {
+	graphqlPath := strings.TrimSpace(sb.GraphQLPath)
+	if graphqlPath == "" && sb.GraphQLPlayground {
+		graphqlPath = defaultGraphQLPath
+	}
+	if graphqlPath != "" {
 		graphqlPath = normaliseOpenAPIPath(graphqlPath)
 		paths[graphqlPath] = graphqlPathItem(graphqlPath, operationIDs)
 		if sb.GraphQLPlayground {

openapi_test.go

@@ -304,6 +304,32 @@ func TestSpecBuilder_Good_GraphQLPlaygroundEndpoint(t *testing.T) {
 	}
 }
 
+func TestSpecBuilder_Good_GraphQLPlaygroundDefaultsToGraphQLPath(t *testing.T) {
+	sb := &api.SpecBuilder{
+		Title:             "Test",
+		Version:           "1.0.0",
+		GraphQLPlayground: true,
+	}
+
+	data, err := sb.Build(nil)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	var spec map[string]any
+	if err := json.Unmarshal(data, &spec); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+
+	paths := spec["paths"].(map[string]any)
+	if _, ok := paths["/graphql"].(map[string]any); !ok {
+		t.Fatal("expected default /graphql path when playground is enabled")
+	}
+	if _, ok := paths["/graphql/playground"].(map[string]any); !ok {
+		t.Fatal("expected default /graphql/playground path when playground is enabled")
+	}
+}
+
 func TestSpecBuilder_Good_WebSocketEndpoint(t *testing.T) {
 	sb := &api.SpecBuilder{
 		Title:   "Test",