An example of test suite

testsuiteexample.spec.ts

import { stub, SinonStub } from 'sinon';

// First describe, class name
describe('MyClass', () => {
  let service: MyService;
  let target: MyClass;

  // Class describe beforeEach, class bootstrap
  beforeEach(() => {
    service = {} as any;
    target = new MyClass(service);
  });

  //method describe, wrapping all test cases for one method
  describe('.myClassMethod()', () => {
    let serviceMethod: SinonStub;
    let anotherClassMethod: SinonStub;

    // Method describe beforeEach, stubs bootstrap, where all the methods that could be called are stubbeds
    beforeEach(() => {
      serviceMethod = service.serviceMethod = stub();
      anotherClassMethod = stub(target, 'anotherClassMethod').returns('anotherClassMethod result');
    });

    // A single test case, where all stubbed methods are called
    it('should do something when something happens', async () => {
      serviceMethod.returns('valid value for this test case');
      const result = await target.myClassMethod();
      expect(serviceMethod).to.have.been.calledOnceWithExatly('some value');
      expect(anotherClassMethod).to.have.been.calledOnceWithEactly('valid value for this test case');
      expect(result).to.be.eq('anotherClassMethod result');
    });

    // Another test case, where one of the stubbed methods are not called
    it('should do another thing when something happens', async () => {
      serviceMethod.returns('another value, valid for this test case');
      const result = await target.myClassMethod();
      expect(serviceMethod).to.have.been.calledOnceWithExatly('some value');
      expect(anotherClassMethod).to.have;not.been.called;
      expect(result).to.be.eq('anotherClassMethod result');
    });
});