public void CanonicalizeExtension_ExtensionWithDotNotAtStart_ReturnsWithDotUppercased()
{
var original = "file.txt";
var expected = $".{original}".ToUpperInvariant();
var result = FileExtensionUtils.CanonicalizeExtension(original);
Assert.AreEqual(expected, result);
}
public void CanonicalizeExtension_Empty_ReturnsEmpty()
{
var ext = FileExtensionUtils.CanonicalizeExtension(string.Empty);
Assert.AreEqual(string.Empty, ext);
}
public void CanonicalizeExtension_Whitespace_ReturnsEmpty()
{
var ext = FileExtensionUtils.CanonicalizeExtension(" \t ");
Assert.AreEqual(string.Empty, ext);
}
public void CanonicalizeExtension_Null_ReturnsNull()
{
var ext = FileExtensionUtils.CanonicalizeExtension(null);
Assert.IsNull(ext);
}
