SameAs

ShouldBeSameAs

var principleSkinner = new Person { Name = "Armin Tamzarian" };
var seymourSkinner = new Person { Name = "Seymour Skinner" };
principleSkinner.ShouldBeSameAs(seymourSkinner);

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Exception

principleSkinner
    should be same as
Seymour Skinner
    but was
Armin Tamzarian

ShouldNotBeSameAs

var person = new Person { Name = "Armin Tamzarian" };
person.ShouldNotBeSameAs(person);

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Exception

person
    should not be same as
Armin Tamzarian
    but was
Armin Tamzarian