1 files changed, 76 insertions, 0 deletions
diff --git a/testing/web-platform/tests/svg/animations/support/animated-path-helpers.js b/testing/web-platform/tests/svg/animations/support/animated-path-helpers.js
new file mode 100644
index 0000000000..3f6fffb907
--- /dev/null
+++ b/testing/web-platform/tests/svg/animations/support/animated-path-helpers.js
@@ -0,0 +1,76 @@
+function roundNumbers(value, digits) {
+  // Round numbers to |digits| decimal places.
+  return value.
+    replace(/-?\d*\.\d+(e-?\d+)?/g, function(n) {
+      return (parseFloat(n).toFixed(digits)).
+        replace(/\.\d+/, function(m) {
+          return m.replace(/0+$/, '');
+        }).
+        replace(/\.$/, '').
+        replace(/^-0$/, '0');
+    });
+}
+
+function normalizeValue(value, digits) {
+  // Round numbers and place whitespace between tokens.
+  return roundNumbers(value, digits).
+    replace(/([\w\d.]+|[^\s])/g, '$1 ').
+    replace(/\s+/g, ' ');
+}
+
+// Transform a path seg list into a path string, rounding numbers to |digits|
+// decimal places.
+function serializePathSegList(list, digits) {
+  function segmentArguments(segment) {
+    const kCommandDescriptor = {
+      'M': ['x', 'y'],
+      'L': ['x', 'y'],
+      'C': ['x1', 'y1', 'x2', 'y2', 'x', 'y'],
+      'Q': ['x1', 'y1', 'x', 'y'],
+      'S': ['x2', 'y2', 'x', 'y'],
+      'T': ['x', 'y'],
+      'A': ['r1', 'r2', 'angle', 'largeArcFlag', 'sweepFlag', 'x', 'y'],
+      'H': ['x'],
+      'V': ['y'],
+      'Z': []
+    };
+    let command = segment.pathSegTypeAsLetter.toUpperCase();
+    return kCommandDescriptor[command].map(field => {
+      return Number(segment[field]).toFixed(digits);
+    });
+  }
+  return Array.from(list).map(segment => {
+    let command = segment.pathSegTypeAsLetter;
+    if (command === 'z')
+      command = 'Z';
+    return [command, ...segmentArguments(segment)].join(' ');
+  }).join(' ');
+}
+
+function normalizeProperty(path_string) {
+  let probePathElement = document.createElementNS('http://www.w3.org/2000/svg', 'path');
+  probePathElement.setAttribute('d', path_string);
+  document.documentElement.appendChild(probePathElement);
+  let string = getComputedStyle(probePathElement).getPropertyValue('d');
+  probePathElement.remove();
+  return string;
+}
+
+// Assert that the animated path data of |target| matches that of
+// |expected_path_string|. Numbers will be rounded to 2 decimal places.
+function assert_animated_path_equals(target, expected_path_string) {
+  const kDecimals = 2;
+  let expected, actual;
+  if ('animatedPathSegList' in target) {
+    let probePathElement = document.createElementNS('http://www.w3.org/2000/svg', 'path');
+    probePathElement.setAttribute('d', expected_path_string);
+    expected = serializePathSegList(probePathElement.pathSegList, kDecimals)
+    actual = serializePathSegList(target.animatedPathSegList, kDecimals);
+  } else if ('d' in target.style) {
+    expected = normalizeValue(normalizeProperty(expected_path_string), kDecimals);
+    actual = normalizeValue(getComputedStyle(target).getPropertyValue('d'), kDecimals);
+  } else {
+    assert_unreached('no animated path data');
+  }
+  assert_equals(actual, expected);
+}