1 files changed, 52 insertions, 0 deletions
diff --git a/dom/canvas/test/webgl-conf/checkout/js/tests/context-methods.js b/dom/canvas/test/webgl-conf/checkout/js/tests/context-methods.js
new file mode 100644
index 0000000000..f6476463d2
--- /dev/null
+++ b/dom/canvas/test/webgl-conf/checkout/js/tests/context-methods.js
@@ -0,0 +1,52 @@
+"use strict";
+
+// Properties to be ignored because they were added in versions of the
+// spec that are backward-compatible with this version
+const IGNORED_METHODS = [
+  // There is no official spec for the commit API yet, the proposal link is:
+  // https://wiki.whatwg.org/wiki/OffscreenCanvas
+  "commit",
+
+  // For WebXR integration:
+  "makeXRCompatible",
+];
+
+function assertFunction(v, f) {
+  try {
+    if (typeof v[f] != "function") {
+      testFailed(`Property either does not exist or is not a function: ${f}`);
+      return false;
+    } else {
+      return true;
+    }
+  } catch(e) {
+    testFailed(`Trying to access the property '${f}' threw an error: ${e.toString()}`);
+  }
+}
+
+function testContextMethods(gl, requiredContextMethods) {
+  const acceptableMethods = [].concat(requiredContextMethods, IGNORED_METHODS);
+
+  let passed = true;
+  requiredContextMethods.forEach(method => {
+    const r = assertFunction(gl, method);
+    passed = passed && r;
+  });
+  if (passed) {
+    testPassed("All WebGL methods found.");
+  }
+  let extended = false;
+  for (let propertyName of Object.getOwnPropertyNames(gl)) {
+    if (typeof gl[propertyName] == "function" && !acceptableMethods.includes(propertyName)) {
+      if (!extended) {
+        extended = true;
+        testFailed("Also found the following extra methods:");
+      }
+      testFailed(propertyName);
+    }
+  }
+
+  if (!extended) {
+    testPassed("No extra methods found on WebGL context.");
+  }
+}