What is the `Assert.That` property for?

Question

Does anybody know what this Assert.That property is for? All members of Assert are static so what is the point of getting an instance?

I know that NUnit has a method Assert.That for hamcrest matchers but a property does not seem to make sense. Maybe this property is for custom assertions as extension methods on Assert?

Answer 1

Assert.That Property

Gets the singleton instance of the Assert functionality.

Users can use this to plug-in custom assertions through C# extension methods. For instance, the signature of a custom assertion provider could be "public static void IsOfType(this Assert assert, object obj)" Users could then use a syntax similar to the default assertions which in this case is "Assert.That.IsOfType<Dog>(animal);"

More documentation is at https://github.com/Microsoft/testfx-docs.