public void ValidateEnumerableToBeNull()
{
// Given
var validator = new EnumerableValidator <int>(null);
// When
validator.BeNull();
// Then
Assert.True(true);
}
public void ValidateEnumerableToBeNullViolated()
{
// Given
var validator = new EnumerableValidator <int>(new List <int>());
// When
var exception = Assert.Throws <XunitException>(() => validator.BeNull("that's the bottom line"));
// Then
Assert.NotNull(exception);
var rn = Environment.NewLine;
Assert.Equal(
$"{rn}validator{rn}contains \"0\" item(s){rn}but was expected to be null{rn}because that's the bottom line",
exception.UserMessage);
}