tinyPngWrongExtFile = await writeTempFile(tinyPngBuffer, ".bin");

alphaPngBuffer = createSolidPngBuffer(64, 64, { r: 255, g: 0, b: 0, a: 128 });

alphaPngFile = await writeTempFile(alphaPngBuffer, ".png");

// Keep this small so the alpha-fallback test stays deterministic but fast.

const size = 24;

fallbackPngBuffer = createGrayscaleAlphaPngBuffer(size, size);

fallbackPngFile = await writeTempFile(fallbackPngBuffer, ".png");

const smallestPng = await optimizeImageToPng(fallbackPngBuffer, 1);

fallbackPngCap = Math.max(1, Math.min(fallbackPngBuffer.length, smallestPng.optimizedSize) - 1);

const jpegOptimized = await optimizeImageToJpeg(fallbackPngBuffer, fallbackPngCap);

if (jpegOptimized.buffer.length > fallbackPngCap) {

throw new Error(

`JPEG fallback did not fit cap (jpeg=${jpegOptimized.buffer.length}, cap=${fallbackPngCap})`,

);

for (const size of [24, 32, 40, 48, 64]) {

const buffer = createGrayscaleAlphaPngBuffer(size, size);

const smallestPng = await optimizeImageToPng(buffer, 1);

const cap = Math.max(1, Math.min(buffer.length, smallestPng.optimizedSize) - 1);

const jpegOptimized = await optimizeImageToJpeg(buffer, cap);

if (jpegOptimized.buffer.length <= cap) {

fallbackPngBuffer = buffer;

fallbackPngFile = await writeTempFile(buffer, ".png");

fallbackPngCap = cap;

break;

}

}

if (!fallbackPngFile) {

throw new Error("No PNG alpha fallback fixture could fit the JPEG cap");

}

});