testing

Testing libraries

• JUnit: Unit testing
• Mockito: Mock dependencies
• Wiremock: Mock Servers, API response
• MockMvc:
• AssertJ: Assertion library (Junit also provide assertion)
• TestNG:

@SpringBootTest

• Used to write integration tests
• load all beans

@Mock

• import org.mockito.Mock

@MockBean

• import org.springframework.boot.test.mock.mockito.MockBean

@Spy

• keeps the methods as it is and modifies only the methods you want????

@WireMockTest

@AutoConfigureWiremock

@MockMvc

Convert Mockito tests to SpringBootTest

• use @MockBean instead of @Mock
• use @Autowired instead of @InjectMocks
• ref: https://stackoverflow.com/questions/66388363/mockito-injecting-mocks-spring-boot-test

AssertJ

• Has fluent style of assertion

assertThat(actual).isNull();
assertThat(notNullActual).isNotNull();
assertThat(actual).contains("great");

• Similar of Jest/Mocha/Chai which have fluent style of assertions

@ParametrizedTest

• can be used to pass different arguments instead of @Test

@ParameterizedTest
@ValueSource(ints = { 0, 2, 4, 1000 })
void testIsEven(int arg) {
    assertTrue(new Calculator().isEven(arg));
}

Lifecycle methods

• @BeforeEach
  • set up new instances of the classes being tested
• @AfterEach
  • clean up side effects
  • provide execution info/report
• @BeforeAll
  • used on static method
  • setup test fixture
  • create and initialize big data structures
  • establish connections to data sources
  • fetch data from databases
• @AfterAll
  • used on static method
  • tear down test fixture
  • close resources and clean everything up
• @BeforeAll and @AfterAll work on static methods so that they can be shared among new test class instances
• A test fixture is a fixed state of objects intended to provide a known and fixed environment for running tests.