Fluent assertions: Assert one OR another value

Question

Using fluent assertions, I would like to assert that a given string contains either one of two strings:

actual.Should().Contain("oneWay").Or().Should().Contain("anotherWay"); 
// eiter value should pass the assertion.
// for example: "you may do it oneWay." should pass, but
// "you may do it thisWay." should not pass

Only if neither of the values is contained, the assertion should fail. This does NOT work (not even compile) as there is no Or() operator.

This is how I do it now:

bool isVariant1 = actual.Contains(@"oneWay");
bool isVariant2 = actual.Contains(@"anotherWay");
bool anyVariant = (isVariant1 || isVariant2);
anyVariant.Should().BeTrue("because blahblah. Actual content was: " + actual);

This is verbose, and the "because" argument must get created manually to have a meaningful output.

Is there a way to do this in a more readable manner? A solution should also apply to other fluent assertion types, like Be(), HaveCount() etc...

I am using FluentAssertions version 2.2.0.0 on .NET 3.5, if that matters.

Answer 1

I would make it an extension to the string assertions. Something like this:

public static void BeAnyOf(this StringAssertions assertions, string[] expectations, string because, params string[] args) {
    Execute.Assertion
           .ForCondition(expectations.Any(assertions.Subject.Contains))
           .BecauseOf(because, args)
           .FailWith("Expected {context:string} to be any of {0}{reason}", expectations);
}

You could even fork the repository and provide me with a Pull Request to make it part of the next version.

Answer 2

Should not this work?

actual.Should().BeOneOf("oneWay", "anotherWay");

Worked for me using v3.1.229.

Answer 3

You could make it a little more readable by writing a simple string extension:

public static class StringExt
{
    public static bool ContainsAnyOf(this string self, params string[] strings)
    {
        return strings.Any(self.Contains);
    }
}

Then you could do this:

actual.ContainsAnyOf("oneWay", "anotherWay").Should().BeTrue("because of this reason");

Unfortunately this doesn't help with the "reason" part of the message, but I think it's a little better.