public void Returns_True_When_Validating_Null_Values()
        {
            // Arrange
            var assertion = new IsNullAssertion(null);

            // Act
            bool result = assertion.IsValid();

            // Assert
            Assert.IsTrue(result);
        }
        public void Returns_False_When_Validating_Non_Null_Values()
        {
            // Arrange
            var assertion = new IsNullAssertion(new object());

            // Act
            bool result = assertion.IsValid();

            // Assert
            Assert.IsFalse(result);
        }