1 files changed, 51 insertions, 0 deletions
diff --git a/testing/web-platform/tests/web-animations/resources/keyframe-utils.js b/testing/web-platform/tests/web-animations/resources/keyframe-utils.js
new file mode 100644
index 0000000000..60fb9781a0
--- /dev/null
+++ b/testing/web-platform/tests/web-animations/resources/keyframe-utils.js
@@ -0,0 +1,51 @@
+'use strict';
+
+// =======================================
+//
+// Utility functions for testing keyframes
+//
+// =======================================
+
+
+// ------------------------------
+//  Helper functions
+// ------------------------------
+
+/**
+ * Test equality between two lists of computed keyframes
+ * @param {Array.<ComputedKeyframe>} a - actual computed keyframes
+ * @param {Array.<ComputedKeyframe>} b - expected computed keyframes
+ */
+function assert_frame_lists_equal(a, b, message) {
+  assert_equals(a.length, b.length, `number of frames: ${(message || '')}`);
+  for (let i = 0; i < Math.min(a.length, b.length); i++) {
+    assert_frames_equal(a[i], b[i],
+                        `ComputedKeyframe #${i}: ${(message || '')}`);
+  }
+}
+
+/** Helper for assert_frame_lists_equal */
+function assert_frames_equal(a, b, name) {
+  assert_equals(Object.keys(a).sort().toString(),
+                Object.keys(b).sort().toString(),
+                `properties on ${name} should match`);
+  // Iterates sorted keys to ensure stable failures.
+  for (const p of Object.keys(a).sort()) {
+    if (typeof b[p] == 'number')
+      assert_approx_equals(a[p], b[p], 1e-6, `value for '${p}' on ${name}`);
+    else if (typeof b[p] == 'object') {
+      for (const key in b[p]) {
+        if (typeof b[p][key] == 'number') {
+          assert_approx_equals(a[p][key], b[p][key], 1e-6,
+                               `value for '${p}.${key}' on ${name}`);
+        } else {
+          assert_equals((a[p][key] || 'undefined').toString(),
+                         b[p][key].toString(),
+                        `value for '${p}.${key}' on ${name}`);
+        }
+      }
+    }
+    else
+      assert_equals(a[p], b[p], `value for '${p}' on ${name}`);
+  }
+}