MockApiInterceptor.java

public class MockApiInterceptor implements Interceptor {

    @Override
    public Response intercept(Interceptor.Chain chain) {
        Request request = chain.request();
        MockResponse mockResponse = getResponse(request);
        return new Response.Builder().request(request)
                .code(mockResponse.code)
                .protocol(Protocol.HTTP_2)
                .body(ResponseBody.create(MediaType.parse("text/json"), mockResponse.body))
                .build();
    }

    private MockResponse getResponse(Request request) {
        String requestUrl = request.url().encodedPath();

        if (requestUrl.endsWith("/login")) {
            // TODO
        } else {
            return new MockResponse("{}");
        }
    }

    private String loadJson(String fileName) {
        try {
            InputStream is = getClass().getClassLoader().getResourceAsStream("responses/" + fileName + ".json");
            int size = is.available();
            byte[] buffer = new byte[size];
            is.read(buffer);
            is.close();
            return new String(buffer, "UTF-8");
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
    }
  
    private static class MockResponse {
        int code;
        String body;

        private MockResponse(String body) {
            this(HttpURLConnection.HTTP_OK, body);
        }

        private MockResponse(int code, String body) {
            this.code = code;
            this.body = body;
        }
    }
}