/// <summary>
/// Allows testing a specific property on the thrown exception
/// </summary>
/// <param name="continuation">Exception-based continuation</param>
/// <param name="fetcher">Func to invoke to get the property you'd like to test</param>
/// <typeparam name="T">Type of the Exception</typeparam>
/// <typeparam name="TValue">Type of the property you're testing</typeparam>
/// <returns>Throw continuation, used to continue with testing the property you just selected</returns>
/// <exception cref="ArgumentException">Thrown if the continuation is not a known ThrowContinuation. Userland implementation of IThrowContinuation is not supported - yet. Make a request if you need it!</exception>
public static IExceptionPropertyContinuation <TValue> With <T, TValue>(
this IThrowContinuation <T> continuation,
Func <T, TValue> fetcher
) where T : Exception
{
var throwContinuation = continuation as ThrowContinuation <T>;
var actual = throwContinuation?.Exception ??
continuation.TryGetPropertyValue <T>("Exception");
if (actual == null)
{
// TODO: can we kinda-duck this to work on user-generated implementations of IThrowContinuation<T>? And do we care to?
throw new ArgumentException(
"With should operate on a ThrowContinuation<T> or at least something with an Exception property that is an Exception.");
}
var exceptionPropertyValue = fetcher(actual);
return(ContinuationFactory.Create <TValue, ExceptionPropertyContinuation <TValue> >(
exceptionPropertyValue,
new WrappingContinuation <T, TValue>(
throwContinuation,
c => exceptionPropertyValue
)
));
}
/// <summary>
/// Verifies that the ArgumentException or derivative was thrown with the
/// expected ParameterName. Effectively shorthand for
/// Expect(func).To.Throw<ArgumentException>.With.Property(e => e.ParamName == parameterName);
/// </summary>
/// <param name="continuation">Continuation to operate on</param>
/// <param name="parameterName">Expected parameter name</param>
/// <typeparam name="T"></typeparam>
/// <returns>Continuation which can be used to do more verification of the exception</returns>
public static IThrowContinuation <T> For <T>(
this IThrowContinuation <T> continuation,
string parameterName
) where T : ArgumentException
{
continuation.AddMatcher(actual =>
{
var passed = actual.ParamName == parameterName;
return(new MatcherResult(
passed,
() =>
continuation.IsNegated() // not actually sure how we'd get here if negated & throwing
? $"Expected ArgumentException with ParameterName other than '{parameterName}', but found exactly that"
: $"Expected ArgumentException with ParameterName '{parameterName}' but found '{actual.ParamName}'"
));
});
return(continuation);
}
