chromium/third_party/blink/web_tests/animations/interpolation/webkit-mask-image-interpolation.html

<!DOCTYPE html>
<meta charset="UTF-8">
<style>
.parent {
  -webkit-mask-image: url(../resources/blue-20.png);
}
.target {
  width: 20px;
  height: 20px;
  display: inline-block;
  background-color: black;
  -webkit-mask-image: url(../resources/stripes-20.png);
}
.expected {
  background-color: green;
  margin-right: 10px;
}
</style>
<body>
<script src="resources/interpolation-test.js"></script>
<script>
// neutral
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: neutralKeyframe,
  fromComputed: 'url(../resources/stripes-20.png)',
  to: 'url(../resources/green-20.png)',
});

// initial
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'initial',
  to: 'url(../resources/green-20.png)',
});

// inherit
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'inherit',
  fromComputed: 'url(../resources/blue-20.png)',
  to: 'url(../resources/green-20.png)',
});

// unset
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'unset',
  to: 'url(../resources/stripes-20.png)',
});

// Image to image
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'url(../resources/stripes-20.png)',
  to: 'url(../resources/blue-20.png)',
});

// Image to gradient
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'url(../resources/stripes-20.png)',
  to: 'linear-gradient(45deg, blue, transparent)',
});

// Gradient to gradient
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'linear-gradient(-45deg, blue, transparent)',
  to: 'linear-gradient(45deg, blue, transparent)',
});

// Keyword to image
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'none',
  to: 'url(../resources/blue-20.png)',
});

// Multiple to multiple
var fromA = 'url(../resources/stripes-20.png)';
var fromB = 'linear-gradient(-45deg, blue, transparent)';
var toA = 'url(../resources/blue-20.png)';
var toB = 'url(../resources/stripes-20.png)';
var from = fromA + ', ' + fromB;
var to = toA + ', ' + toB;
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: from,
  to: to,
});

// Single to multiple
from = 'url(../resources/blue-20.png)';
toA = 'url(../resources/stripes-20.png)';
toB = 'url(../resources/blue-20.png)';
to = toA + ', ' + toB;
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: from,
  to: to,
});

// Multiple mismatched types
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'url(../resources/blue-20.png), none',
  to: 'url(../resources/stripes-20.png), url(../resources/blue-20.png)',
});
</script>
</body>