public void shouldReturnCompletions() throws Exception {
client.handle(post(url("execute")).form("expression", "expr_1 = 42").build());
client.handle(post(url("execute")).form("expression", "expr_2 = 21").build());
client.handle(post(url("execute")).form("expression", "expr_3 = 7").build());
Response response = client.handle(get(url("completions")).query("expression", "prefix expr_").build());
assertThat(response.status(), is(Status.OK));
assertThat(body(response), is(model()
.add("expression", "prefix expr_")
.add("position", "7")
.add("candidates",
asList(