protected void _RunGetIndexOfFirstCharacterToEncodeUtf16_BmpExtendedValidCharsOnly(char bmpAllowedChar)
{
// Loop from 96 elements all the way down to 0 elements, which tests that we're
// not overrunning our read buffers.
var span = _boundedChars.Span;
_boundedChars.MakeWriteable();
span.Fill(bmpAllowedChar); // make buffer all-valid
_boundedChars.MakeReadonly();
for (int i = 96; i >= 0; i--)
{
Assert.Equal(-1, _encoder.FindFirstCharacterToEncodeUtf16(span.Slice(span.Length - i)));
}
// Also check from the beginning of the buffer just in case there's some alignment weirdness
// in the SIMD-optimized code that causes us to read past where we should.
_boundedChars.MakeWriteable();
for (int i = 96; i >= 0; i--)
{
span[i] = _disallowedChar; // make this char invalid (ASCII)
Assert.Equal(-1, _encoder.FindFirstCharacterToEncodeUtf16(span.Slice(0, i)));
}
}