@Test
    @Issue("2628")
    void invalidIndentation(JenkinsConfiguredWithCodeRule j) throws Exception {
        j.jenkins.setCrumbIssuer(null);

        WebResponse response = performYamlValidation(j, "jenkins:\nsystemMessage: \"Bad indentation\"");

        assertThat(response.getContentType(), is("application/json"));

        // Verify the response contains valid JSON regardless of status code
        String responseString = response.getContentAsString();
        JSONArray jsonResponse = JSONArray.fromObject(responseString);

        // The response should be a non-empty JSON array
        assertThat("Should return error details", jsonResponse.size() > 0, is(true));
    }
Tests that YAML with incorrect indentation returns proper JSON response.
test-harness/src/test/java/io/jenkins/plugins/casc/YamlValidationTest.java