@Test
        @FeatureRequirement(featureClass = Graph.Features.VariableFeatures.class, feature = FEATURE_VARIABLES)
        public void testGraphVariablesSet() throws Exception {
            try {
                graph.variables().set(key, val);
                fail(String.format("Setting an annotation with these arguments [key: %s value: %s] should throw an exception", key, val));
            } catch (Exception ex) {
                validateException(expectedException, ex);
            }
        }
Test exceptions around {@link Graph.Variables}.
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/VariablesTest.java