Tell us about your runtime:

• QUnit version: 2.7.1
• What environment are you running QUnit in? (e.g., browser, Node): Browser
• How are you running QUnit? (e.g., script, testem, Grunt): Script

What are you trying to do?

Code that reproduces the problem:

https://jsfiddle.net/bzomqak8/11/

class Foo {
  constructor(a = 1) {
    this.a = a;
  }
}

Object.defineProperty(Foo.prototype, 'b', {
  enumerable: true,
  get() {
    return new Foo(this.a + 1);
  }
})

QUnit.test("hello test", function(assert) {
  assert.deepEqual(new Foo(), new Foo());
});

If you have any relevant configuration information, please include that here:

What did you expect to happen?

I expected QUnit to not compare computed properties.

What actually happened?

QUnit compares computed properties by using a for..in loop which (due to BFS) recurses infinitely without ever hitting a stack limit.

This is a minimal reproduction extracted from one of our Ember apps. In the actual app we use an Ember.Object and a computed property instead of the code above, but the effect is the same.