1 files changed, 70 insertions, 0 deletions
diff --git a/testing/web-platform/tests/svg/animations/animate-calcMode-spline-by.html b/testing/web-platform/tests/svg/animations/animate-calcMode-spline-by.html
new file mode 100644
index 0000000000..5ce9bcc763
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+++ b/testing/web-platform/tests/svg/animations/animate-calcMode-spline-by.html
@@ -0,0 +1,70 @@
+<!doctype html>
+<html>
+<meta charset="utf-8">
+<title>Test calcMode spline with by animation. You should see a green 100x100 rect and only PASS messages</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/SVGAnimationTestCase-testharness.js"></script>
+
+<svg>
+</svg>
+
+<script>
+var rootSVGElement = document.querySelector("svg");
+var epsilon = 1.0;
+
+// Setup test document
+var rect = createSVGElement("rect");
+rect.setAttribute("id", "rect");
+rect.setAttribute("x", "100");
+rect.setAttribute("width", "100");
+rect.setAttribute("height", "100");
+rect.setAttribute("fill", "green");
+rect.setAttribute("onclick", "executeTest()");
+
+var animate = createSVGElement("animate");
+animate.setAttribute("id", "animation");
+animate.setAttribute("attributeName", "x");
+animate.setAttribute("by", "-100");
+animate.setAttribute("begin", "0s");
+animate.setAttribute("dur", "4s");
+animate.setAttribute("keyTimes", "0;1");
+animate.setAttribute("keySplines", "0.25 .5 .25 0.85");
+animate.setAttribute("calcMode", "spline");
+rect.appendChild(animate);
+rootSVGElement.appendChild(rect);
+
+// Setup animation test
+function sample1() {
+    // Check initial/end conditions
+    assert_approx_equals(rect.x.animVal.value, 100, epsilon);
+    assert_equals(rect.x.baseVal.value, 100);
+}
+
+function sample2() {
+    // Check half-time conditions
+    assert_approx_equals(rect.x.animVal.value, 18.8, epsilon);
+    assert_equals(rect.x.baseVal.value, 100);
+}
+
+function sample3() {
+    // Check just before-end conditions
+    assert_approx_equals(rect.x.animVal.value, 0, epsilon);
+    assert_equals(rect.x.baseVal.value, 100);
+}
+
+smil_async_test((t) => {
+    const expectedValues = [
+        // [animationId, time, sampleCallback]
+        ["animation", 0.0,   sample1],
+        ["animation", 2.0,   sample2],
+        ["animation", 3.999, sample3],
+        ["animation", 4.001, sample1]
+    ];
+
+    runAnimationTest(t, expectedValues);
+});
+
+window.clickX = 150;
+
+</script>
+\ No newline at end of file