added tests for logger service

Author: mrachek

src/app/courses/services/logger.service.spec.ts

@@ -0,0 +1,22 @@
+import { LoggerService } from './logger.service';
+import { TestBed } from '@angular/core/testing';
+
+describe('LoggerService', () =>{
+  let service: LoggerService;
+  let logSpy: any;
+
+  beforeEach(() => {
+    TestBed.configureTestingModule({
+      providers: [LoggerService]
+    });
+    service = TestBed.inject(LoggerService);
+    logSpy = spyOn(service, 'log');
+  });
+
+  it('should call log method with the correct message', () => {
+    const message = 'Test message';
+    service.log(message);
+    expect(logSpy).toHaveBeenCalled();
+    expect(logSpy).toHaveBeenCalledWith(message);
+  });
+});