NG Assertions

RestResponse.assertThat() returns a ResponseAssertion (package org.apache.juneau.rest.client.assertion) for fluent checks. Failures throw AssertionError, so they work directly in JUnit tests.

try (var resp = client.get("/users/42").run()) {
    resp.assertThat()
        .isOk()
        .header("Content-Type").contains("json").and()
        .header("ETag").isPresent().and()
        .body().contains("\"id\":42").and();
}

ResponseAssertion

Method	Checks
statusCode()	Returns an integer assertion on the status.
isOk()	Status is 2xx.
isClientError() / isServerError()	Status is 4xx / 5xx.
header(name)	Switches to a ResponseHeaderAssertion.
body()	Switches to a ResponseBodyAssertion.
and()	Returns to the parent assertion.

ResponseHeaderAssertion

isPresent(), isAbsent(), equals(String), contains(String), startsWith(String), integerEquals(int), and().

ResponseBodyAssertion

equals(String), contains(String), startsWith(String), isEmpty(), isNotEmpty(), and().

Body assertions read the body, so they consume it. Use them instead of, not in addition to, body().as(...) on the same response.

Assertions versus exceptions

• assertThat() is for tests: it throws AssertionError.
• assertOk() / assertStatus(int) on the response are for application code: they throw RestCallException, which you can catch and inspect with getStatusCode().