@Test
    public void resolve_JsonMissingKey() {
        String input = "{ \"b\": 2 }";
        environment.set("FOO", input);
        String output = resolve("${json:a:${FOO}}");
        assertTrue(
                logContains(
                        "Configuration import: JSON secret did not contain the specified key 'a'. Will default to empty string."));
        assertThat(output, equalTo(""));
    }
Test a mix of JSON and other lookups
plugin/src/test/java/io/jenkins/plugins/casc/SecretSourceResolverTest.java