@Test public void shouldReturn200ForMultipartFilePost() throws IOException { File uploadFile = createRandomContentsFile(); RequestBody formBody = new MultipartBody.Builder() .setType(MultipartBody.FORM) .addFormDataPart("someParam", "someValue") .addFormDataPart("file", "somefile.dat", RequestBody.create( MediaType.parse("application/octet-stream"), uploadFile)) .build(); Request request = new Request.Builder() .url(getFullUrl("/example/")) .post(formBody) .build(); Response response = client.newCall(request).execute(); assertThat(response.isSuccessful(), is(true)); assertThat(response.code(), is(200)); String responseBodyString = response.body().string(); assertThat(responseBodyString, not(isEmptyOrNullString())); }