AttributeExists Constraint

AttributeExistsConstraint tests for the existence of an attribute on a type.

Usage

Has.Attribute(Type attributeType)
Has.Attribute<TAttribute>()

The generic form requires TAttribute : Attribute, so passing a type that isn't an attribute is a compiler error.

Note

In NUnit 4 and earlier, the generic form accepted any type. Passing a type that isn't an attribute compiled, but the test failed when it ran.

Examples

[Serializable]
public class SerializableClass { }

[Test]
public void AttributeExistsConstraint_Examples()
{
    // Test that a type has an attribute
    Assert.That(typeof(SerializableClass), Has.Attribute<SerializableAttribute>());

    // Negative test
    Assert.That(typeof(TypeConstraintSnippets), Has.No.Attribute<SerializableAttribute>());
}

Notes

  1. When no further constraint is chained, Has.Attribute creates an AttributeExistsConstraint.
  2. When a constraint is chained (e.g., .Property("Name")), it becomes an AttributeConstraint.
  3. The constraint works on any object that implements ICustomAttributeProvider, such as Type, MethodInfo, and Assembly.

See Also