public void TestToExpression() { // GIVEN necessary arguments Mock <IParameterProvider <object> > parameterProvider = new Mock <IParameterProvider <object> >(); Expression formatProvider = Expression.Constant(null); // WHEN the text segment is converted to an expression TextSegment textSegment = new TextSegment("a string"); Expression result = textSegment.ToExpression(parameterProvider.Object, formatProvider); // THEN the expression is a constant Assert.IsInstanceOfType(result, typeof(ConstantExpression)); // AND the expression contains the correct string Assert.AreEqual("a string", ((ConstantExpression)result).Value); // AND the parameter provider was not interacted with parameterProvider.VerifyNoOtherCalls(); }