StartsWith Constraint

StartsWithConstraint tests that a string begins with the expected substring.

Usage

Does.StartWith(string expected)
Does.Not.StartWith(string expected)

Modifiers

.IgnoreCase
.Using(StringComparison comparisonType)
.Using(CultureInfo culture)

Examples

[Test]
public void StartsWithConstraint_Examples()
{
    string phrase = "Make your tests fail before passing!";

    Assert.That(phrase, Does.StartWith("Make"));
    Assert.That(phrase, Does.StartWith("MAKE").IgnoreCase);
    Assert.That(phrase, Does.Not.StartWith("Break"));
}

Specifying a StringComparison

[Test]
public void StartsWithConstraint_StringComparison_Examples()
{
    Assert.That("Hello World!", Does.StartWith("HELLO").Using(StringComparison.OrdinalIgnoreCase));
    Assert.That("Hello World!", Does.StartWith("Hello").Using(StringComparison.Ordinal));
}

Specifying a CultureInfo

The Using(CultureInfo) modifier allows for culture-specific string comparisons. It can be combined with .IgnoreCase for case-insensitive culture-aware comparisons:

// Using Turkish culture where 'i' and 'I' have special casing rules
Assert.That("TITLE text", Does.StartWith("title").IgnoreCase.Using(new CultureInfo("tr-TR")));

// Culture-specific comparison without case-insensitivity
Assert.That("Straße Street", Does.StartWith("Straße").Using(new CultureInfo("de-DE")));

Notes

Only one Using modifier may be specified. Attempting to use multiple Using modifiers will throw an InvalidOperationException.