create([ 'school_id' => null, ]); $service = app(SchoolIdAssignmentService::class); $schoolId = $service->assignToUser($user->id); $this->assertNotNull($schoolId); $this->assertSame($schoolId, User::query()->findOrFail($user->id)->school_id); } public function test_assign_returns_existing_school_id(): void { $user = User::factory()->create([ 'school_id' => '2500001', ]); $service = app(SchoolIdAssignmentService::class); $schoolId = $service->assignToUser($user->id); $this->assertSame('2500001', $schoolId); } }