String comparison without whitespace

[Crown0815]

In some situations a string comparison without taking whitespace into account is desirable.

A use-case would be JSON string comparison, which should be whitespace agnostic but requires perfect whitespace matching when using the EqualConstraint.

Current solution to the issue

To avoid this issue I have to write

Assert.That(resultingJsonString.WithoutWhitespace(), Is.EqualTo(expectedJsonString.WithoutWhitespace()));

where WithoutWhitespace() is an extension method removing all whitespace characters.

Prefered syntax

It would be more fluent to write

Assert.That(resultingJsonString, Is.EqualTo(expectedJsonString).IgnoreWhitespace));

IgnoreWhitespace was inspired by the existing IgnoreCase configuration.

[Dreamescaper]

You can create extension method similar to something like this:

        private static readonly Regex _whitespaceRegex = new Regex(@"\w+");

        private static string ReplaceSpaces(string s) => _whitespaceRegex.Replace(s, " ");

        public static EqualConstraint IgnoreWhitespace(this EqualConstraint constraint)
        {
            return constraint.Using<string>((actual, expected) => ReplaceSpaces(actual) == ReplaceSpaces(expected));
        }

So you'd be able to write something like:
Assert.That(resultingJsonString, Is.EqualTo(expectedJsonString).IgnoreWhitespace()));

[neilboyd]

@Dreamescaper There are a couple of typos in the example:
it should be \s+, not \w+, and Replace(s, ""), not Replace(s, ""). But the idea is good 😃

[ivan-gurin]

Some other expression types would also benefit of similar option, say Is.Null.Or.Empty.IgnoreWhitespace (unless this is already implemented somehow)