String jsonString = "{\"foo\": \"bar\"}";
@SuppressWarnings("unchecked")
protected <T> T executeExpression(String expression) {
final TestVariableScope varScope = new TestVariableScope();
final Expression compiledExpression = processEngineConfiguration.getExpressionManager()
.createExpression(expression);
return (T) processEngineConfiguration.getCommandExecutorTxRequired()