function assertTarget(
    target, expectedElement, expectedTargetCorner, expectedMenuCorner,
    expectedEventType, expectedMargin) {
  const expectedTarget = {
    element_: expectedElement,
    targetCorner_: expectedTargetCorner,
    menuCorner_: expectedMenuCorner,
    eventType_: expectedEventType,
    margin_: expectedMargin,
  };

  assertObjectEquals('Target does not match.', expectedTarget, target);
}
Asserts properties of `target` matches the expected value.
@param {Object} target The target specifying how the popup menu should be
    attached to an anchor.
@param {Element} expectedElement The expected anchoring element.
@param {Corner} expectedTargetCorner The expected value of the
    `target.targetCorner_` property.
@param {Corner} expectedMenuCorner The expected value of the
    `target.menuCorner_` property.
@param {EventType} expectedEventType The expected value of the
    `target.eventType_` property.
@param {Box} expectedMargin The expected value of the `target.margin_`
    property.