public void ValidateDoubleToBeNegative()
{
// Given
var validator = new DoubleValidator(-42);
// When
validator.BeNegative();
// Then
Assert.True(true);
}
public void ValidateDoubleToBeNegativeViolated()
{
// Given
var validator = new DoubleValidator(0);
// When
var exception = Assert.Throws <XunitException>(() => validator.BeNegative(because: "that's the bottom line"));
// Then
Assert.NotNull(exception);
var rn = Environment.NewLine;
Assert.Equal(
$"{rn}validator{rn}is \"0\"{rn}but was expected to have a negative value{rn}because that's the bottom line",
exception.UserMessage);
}