public void EvaluateStringConcat()
{
Assert.AreEqual("foobar", this.EvaluateExpression("'foo'.concat('bar')"));
Assert.AreEqual("foo", this.EvaluateExpression("'foo'.concat()"));
Assert.AreEqual("foo42", this.EvaluateExpression("'foo'.concat(42)"));
Assert.AreEqual("hello, world", this.EvaluateExpression("'hello'.concat(', ', 'world')"));
Assert.AreEqual("foonull", this.EvaluateExpression("'foo'.concat(null)"));
}