UserRepositoryImplTest.kt

@file:OptIn(ExperimentalCoroutinesApi::class)

class UserRepositoryImplTest {

    private lateinit var repository: UserRepository
    private lateinit var testApis: TestApis
    private lateinit var mockWebServer: MockWebServer

    @Before
    fun setUp() {
        mockWebServer = MockWebServer()
        mockWebServer.start()
        testApis = RetrofitHelper.testApiInstance(mockWebServer.url("/").toString())
        repository = UserRepositoryImpl(testApis)
    }

    @After
    fun tearDown() {
        mockWebServer.shutdown()
    }

    @Test
    fun `for no users, api must return empty with http code 200`() = runTest {
        val users = emptyList<User>()
        val expectedResponse = MockResponse()
            .setResponseCode(HttpURLConnection.HTTP_OK)
            .setBody(Gson().toJson(users))
        mockWebServer.enqueue(expectedResponse)

        val actualResponse = repository.getAllUsers()
        assertThat(actualResponse.body).hasSize(0)
    }

    @Test
    fun `for multiple users, api must return all users with http code 200`() = runTest {
        val users = listOf(
            User(1,"Saurabh","Delhi","India"),
            User(2,"Zergain","London","UK"),
        )
        val expectedResponse = MockResponse()
            .setResponseCode(HttpURLConnection.HTTP_OK)
            .setBody(Gson().toJson(users))
        mockWebServer.enqueue(expectedResponse)

        val actualResponse = repository.getAllUsers()
        assertThat(actualResponse.body).hasSize(2)
        assertThat(actualResponse.body).isEqualTo(users)
    }

    @Test
    fun `for server error, api must return with http code 5xx`() = runTest {
        val expectedResponse = MockResponse()
            .setResponseCode(HttpURLConnection.HTTP_INTERNAL_ERROR)
        mockWebServer.enqueue(expectedResponse)

        val actualResponse = repository.getAllUsers()
        assertThat(actualResponse.httpCode).isEqualTo(HttpURLConnection.HTTP_INTERNAL_ERROR)
    }

    @Test
    fun `for server error, api must return with http code 5xx and error message`() = runTest {
        val expectedResponse = MockResponse()
            .setResponseCode(HttpURLConnection.HTTP_INTERNAL_ERROR)
        mockWebServer.enqueue(expectedResponse)

        val actualResponse = repository.getAllUsers()
        assertThat(actualResponse.httpCode).isEqualTo(HttpURLConnection.HTTP_INTERNAL_ERROR)
        assertThat(actualResponse.errorMessage).isEqualTo("server error")
    }

    @Test
    fun `for user id, api must return with http code 200 and user object`() = runTest {
        val mockUser = User(1,"Saurabh","Delhi","India")
        val expectedResponse = MockResponse()
            .setResponseCode(HttpURLConnection.HTTP_OK)
            .setBody(Gson().toJson(mockUser))
        mockWebServer.enqueue(expectedResponse)

        val actualResponse = repository.getUserById(1)
        assertThat(actualResponse.httpCode).isEqualTo(HttpURLConnection.HTTP_OK)
        assertThat(actualResponse.errorMessage).isNull()
        assertThat(actualResponse.body).isEqualTo(mockUser)
    }

    @Test
    fun `for user id not available, api must return with http code 404 and null user object`() = runTest {
        val expectedResponse = MockResponse()
            .setResponseCode(HttpURLConnection.HTTP_NOT_FOUND)
        mockWebServer.enqueue(expectedResponse)

        val actualResponse = repository.getUserById(1)
        assertThat(actualResponse.httpCode).isEqualTo(HttpURLConnection.HTTP_NOT_FOUND)
        assertThat(actualResponse.body).isNull()
    }

}