Mocking HTTP responses (experimental)

EXPERIMENTAL
MockServer is still experimental and most of the APIs are designed for Kotlin. MockServer is multiplatform but if you're using Java only, we recommend using OkHttp MockWebServer which will provide idiomatic Java APIs.

MockServer implements an HTTP server that you can use to mock responses. It's useful for testing specific server behaviors, such as error cases, HTTP headers, and timeouts. Using it requires minimal changes to your production code, because you only need to change your serverUrl.

note
Apollo Kotlin MockServer is developed in a separate repository. Head to https://github.com/apollographql/apollo-kotlin-mockserver for API docs and comprehensive documentation.

Add the dependency to your project's build.gradle file:

Kotlin
build.gradle[.kts]
1dependencies { 2 testImplementation("com.apollographql.mockserver:apollo-mockserver:0.0.1") 3}

And here's how to use it:

Kotlin
1// Create a mock server 2val mockServer = MockServer() 3 4// Provide its URL to your ApolloClient 5val apolloClient = ApolloClient.Builder().serverUrl(mockServer.url()).store(store).build() 6 7// Enqueue HTTP responses 8mockServer.enqueueString("""{"data": {"random": 42}}""") 9mockServer.enqueue( 10 MockResponse( 11 body = "Internal server error", 12 statusCode = 500, 13 headers = mapOf("X-Test" to "true"), 14 // Optionally pass a delay to simulate network latency 15 delayMillis = 1000L, 16 ) 17) 18 19// Execute queries 20val response1 = apolloClient 21 .query(GetRandomQuery()) 22 .execute() 23 24val response2 = apolloClient 25 .query(GetRandomQuery()) 26 .execute() 27 28// Don't forget to stop the server when you're done 29mockServer.stop()

The enqueue function normally takes a MockResponse as a parameter, but it also supports a shorthand version that takes a String (both are shown above).

Advanced usage

By default, MockServer is configured with a QueueMockServerHandler, which returns responses in the order they've been enqueued. If you need more control over the responses to return, you can implement your own MockServerHandler and pass it to the MockServer:

Kotlin
1val customHandler = object : MockServerHandler { 2 override fun handle(request: MockRequest): MockResponse { 3 return if (/* Your custom logic here */) { 4 MockResponse( 5 body = """{"data": {"random": 42}}""", 6 headers = mapOf("X-Test" to "true"), 7 ) 8 } else { 9 MockResponse( 10 body = "Internal server error", 11 statusCode = 500, 12 ) 13 } 14 } 15} 16 17val mockServer = MockServer(customHandler)

Note that if you use a custom MockServerHandler, calling MockServer.enqueue() is no longer possible because it expects the handler to be a QueueMockServerHandler.