module foo {
    yang-version 1;

    namespace "org.namespace.test.foo";
    prefix "foo";

    description "foo";

    revision "2016-01-01" {
        description "Initial version.";
    }

    grouping test-grouping {
        leaf test-leaf {
            type string;
        }
    }

    container test-container {
        uses test-grouping {
            refine test-leaf {
                description "refined description";
                must "test-leaf != 'not test message 1'" {
                    error-message "not test message 1";
                }
                must "test-leaf != 'not test message 2'" {
                    error-message "not test message 2";
                }
            }
        }
    }
}