private static void ExecuteTestCase(string expression, int value, IDictionary <Variable, int> variableValues = null)
{
var expressionInterpreter = new ExpressionInterpreter(expression);
var result = expressionInterpreter.CalculateWith(variableValues);
Assert.AreEqual(value, result, $"Expected result for expression '{expression}' was {value} but got {result}");
}
