Preserve null in project update for taskManager

Adjusts mock project update logic to correctly preserve null values for taskManager when explicitly set, ensuring accurate test behavior for scenarios like disconnectTaskManager. Also refactors test setup in GitHub routes integration test for clarity.

Author: neSpecc

test/integrations/github-routes.test.ts

@@ -681,8 +681,8 @@ describe('GitHub Routes - /integration/github/connect', () => {
         workspaceId,
       });
       mockProject.taskManager = null;
+      mockProject.updateProject = jest.fn().mockResolvedValue(undefined);
       mockGetInstallationForRepository.mockResolvedValue({});
-      mockProject.updateProject.mockResolvedValue(undefined);
 
       const factories: ContextFactories = {
         projectsFactory: {

test/resolvers/project.test.ts

@@ -51,7 +51,12 @@ function createMockProject(options: {
   const mockUpdateProject = jest.fn().mockImplementation(async (data) => {
     /**
      * Return updated project with new data
+     * Preserve null when explicitly passed (e.g. disconnectTaskManager sets taskManager: null)
      */
+    const nextTaskManager = data.taskManager !== undefined
+      ? data.taskManager
+      : (taskManager ?? undefined);
+
     return {
       _id: new ObjectId(projectId),
       workspaceId: new ObjectId(workspaceId),
@@ -60,7 +65,7 @@ function createMockProject(options: {
       token: 'test-token',
       notifications: [],
       eventGroupingPatterns: [],
-      taskManager: data.taskManager !== undefined ? (data.taskManager ?? undefined) : (taskManager ?? undefined),
+      taskManager: nextTaskManager,
     };
   });