### Question:
Util { public static boolean isExpression(String value) { return value != null && value.startsWith("${") && value.endsWith("}"); } private  Util(); static String getNameFromAddress(final ModelNode address); static String getNameFromAddress(PathAddress address); static ModelNode createAddOperation(final PathAddress address); static ModelNode createAddOperation(); static ModelNode createRemoveOperation(final PathAddress address); static ModelNode createOperation(final String operationName, final PathAddress address); static ModelNode createOperation(final OperationDefinition operationDefinition, final PathAddress address); static ModelNode createEmptyOperation(String operationName, final PathAddress address); static ModelNode getEmptyOperation(String operationName, ModelNode address); static ModelNode getResourceRemoveOperation(final PathAddress address); static ModelNode getWriteAttributeOperation(ModelNode address, String attributeName, String value); static ModelNode getWriteAttributeOperation(final PathAddress address, String attributeName, int value); static ModelNode getWriteAttributeOperation(final PathAddress address, String attributeName, boolean value); static ModelNode getWriteAttributeOperation(final ModelNode address, String attributeName, ModelNode value); static ModelNode getWriteAttributeOperation(final PathAddress  address, String attributeName, String value); static ModelNode getWriteAttributeOperation(final PathAddress address, String attributeName, ModelNode value); static ModelNode getReadAttributeOperation(final PathAddress address, String attributeName); static ModelNode getReadResourceDescriptionOperation(final PathAddress address); static ModelNode getUndefineAttributeOperation(final PathAddress address, String attributeName); static boolean isExpression(String value); static ModelNode getOperation(final String operationName, final PathAddress address, final ModelNode params); static ModelNode getOperation(String operationName, ModelNode address, ModelNode params); static PathAddress getParentAddressByKey(PathAddress address, String parentKey); static ModelNode validateOperation(ModelNode operation);  }### Answer:
@Test public void testIsExpression() { assertThat(Util.isExpression(""), is(false)); assertThat(Util.isExpression("${test"), is(false)); assertThat(Util.isExpression("${test}"), is(true)); }