public void TestToExpressionWithDateTime()
{
// GIVEN expressions for parameters
Mock <IParameterProvider <object> > parameterProvider = new Mock <IParameterProvider <object> >();
Expression formatProvider = Expression.Constant(null, typeof(IFormatProvider));
// AND the parameter provider can find the property
Expression dateTimeExpression = Expression.Constant(DateTime.Now);
parameterProvider.Setup(p => p.GetParameter("DateTimeProperty")).Returns(dateTimeExpression);
// AND the parameter provider wraps the expression in a null check
Expression wrappedDateTimeExpression = Expression.Constant(new object());
parameterProvider.Setup(p => p.WrapWithNullCheck(dateTimeExpression, It.IsAny <Expression>())).Returns(wrappedDateTimeExpression);
// WHEN the param segment is converted to an expression
FormattedParamSegment paramSegment = new FormattedParamSegment("DateTimeProperty", "yyyy-MM-dd");
Expression result = paramSegment.ToExpression(parameterProvider.Object, formatProvider);
// THEN the expression wrapped was a method call to the ToString method
object toTest = parameterProvider.Invocations[1].Arguments[1];
Assert.IsInstanceOfType(toTest, typeof(MethodCallExpression));
MethodInfo?methodInfo2 = typeof(DateTime).GetMethod("ToString", new Type[] { typeof(string), typeof(IFormatProvider) });
Assert.AreSame(methodInfo2, ((MethodCallExpression)toTest).Method);
Assert.AreEqual(2, ((MethodCallExpression)toTest).Arguments.Count);
Assert.IsInstanceOfType(((MethodCallExpression)toTest).Arguments[0], typeof(ConstantExpression));
Assert.AreSame("yyyy-MM-dd", ((ConstantExpression)((MethodCallExpression)toTest).Arguments[0]).Value);
Assert.AreSame(formatProvider, ((MethodCallExpression)toTest).Arguments[1]);
// AND the expression contains that returned by the parameter provider
Assert.AreSame(dateTimeExpression, ((MethodCallExpression)toTest).Object);
// AND the expression returned is the wrapped object expression
Assert.AreSame(wrappedDateTimeExpression, result);
}
public void TestToExpressionWithInvalidProperty()
{
// GIVEN expressions for parameters
Mock <IParameterProvider <object> > parameterProvider = new Mock <IParameterProvider <object> >();
Expression formatProvider = Expression.Constant(null);
// AND the parameter provider can find the property but it's not IFormattable
Expression dateTimeExpression = Expression.Constant(new object());
parameterProvider.Setup(p => p.GetParameter("ObjectProperty")).Returns(dateTimeExpression);
// WHEN the param segment is converted to an expression with a property that is not IFormattable
// THEN an exception is thrown
FormattedParamSegment paramSegment = new FormattedParamSegment("ObjectProperty", "yyyy-MM-dd");
FormatStringSyntaxException e = Assert.ThrowsException <FormatStringSyntaxException>(() => paramSegment.ToExpression(parameterProvider.Object, formatProvider));
Assert.AreEqual("Property 'ObjectProperty' does not return a type implementing IFormattable hence a format string cannot be applied to it.", e.Message);
}