StartsWith Constraint

StartsWithConstraint tests for an initial string.

Constructor

StartsWithConstraint(string expected)

Syntax

Does.StartWith(string expected)
StartsWith(string expected)

Modifiers

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

Examples of Use

string phrase = "Make your tests fail before passing!";

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

Specifying a StringComparison

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

  1. StartsWith may appear only in the body of a constraint expression or when the inherited syntax is used.
  2. Only one Using modifier may be specified. Attempting to use multiple Using modifiers will throw an InvalidOperationException.