1 files changed, 61 insertions, 1 deletions
diff --git a/js/testing/testing.ts b/js/testing/testing.ts
index 437cb0f38..4cf7ea27f 100644
--- a/js/testing/testing.ts
+++ b/js/testing/testing.ts
@@ -13,7 +13,67 @@
    limitations under the License.
 */
 
-export { assert, assertEqual, equal } from "./util";
+// Do not add imports in this file in order to be compatible with Node.
+
+export function assertEqual(actual: unknown, expected: unknown, msg?: string) {
+  if (!equal(actual, expected)) {
+    let actualString: string;
+    let expectedString: string;
+    try {
+      actualString = String(actual);
+    } catch (e) {
+      actualString = "[Cannot display]";
+    }
+    try {
+      expectedString = String(expected);
+    } catch (e) {
+      expectedString = "[Cannot display]";
+    }
+    console.error(
+      "assertEqual failed. actual =",
+      actualString,
+      "expected =",
+      expectedString
+    );
+    if (!msg) {
+      msg = `actual: ${actualString} expected: ${expectedString}`;
+    }
+    throw new Error(msg);
+  }
+}
+
+export function assert(expr: boolean, msg = "") {
+  if (!expr) {
+    throw new Error(msg);
+  }
+}
+
+// TODO(ry) Use unknown here for parameters types.
+// tslint:disable-next-line:no-any
+export function equal(c: any, d: any): boolean {
+  const seen = new Map();
+  return (function compare(a, b) {
+    if (Object.is(a, b)) {
+      return true;
+    }
+    if (a && typeof a === "object" && b && typeof b === "object") {
+      if (seen.get(a) === b) {
+        return true;
+      }
+      if (Object.keys(a).length !== Object.keys(b).length) {
+        return false;
+      }
+      for (const key in { ...a, ...b }) {
+        if (!compare(a[key], b[key])) {
+          return false;
+        }
+      }
+      seen.set(a, b);
+      return true;
+    }
+    return false;
+  })(c, d);
+}
 
 export type TestFunction = () => void | Promise<void>;