Fix test suite compatibility with Navigation API router (#135)

* fix: Handle traversal navigation when canIntercept is false

For back/forward traversals, canIntercept may be false when the destination
entry was created via history.replaceState, but the URL changes regardless.
Only gate on canIntercept for push/replace navigations.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* test: Remove non-configurable window.location stub

sinon cannot stub window.location in modern browsers as it is non-configurable
and non-writable. The stub was a leftover from before the Navigation API refactor
— location.assign/replace are no longer used in the router or tests.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* test: Fix _top/_parent navigation crashing WTR in CI

WTR runs tests inside an iframe. Clicking links with target="_top" or
target="_parent" targets the WTR runner frame (canIntercept=false), so
calling e.intercept() unconditionally throws and lets the navigation
escape — crashing the entire test session.

Fix by:
- Checking canIntercept before calling e.intercept() in test handlers
- Skipping _top/_parent tests (like _blank) since they can't be
  meaningfully tested in an iframe context

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* test: Remove unused sinon afterEach cleanup

sinon.restore() in afterEach was only needed for the window.location stub
which was removed. The remaining sinon.spy (scrollTo) is restored manually.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* revert: Undo traversal/canIntercept handling that broke tests

Reverts the isTraversal guard and conditional e.intercept() from
router.js, and restores the original test handler behavior.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix: Gate navigation intercept on canIntercept check

Move canIntercept to the top of the guard conditions so navigations
that cannot be intercepted (e.g. back/forward to history.replaceState
entries) are skipped cleanly without calling e.intercept().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* test: Revert scope handler to unconditional intercept

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* test: Skip navigation tests, add a big ol' TODO

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Ryan Christian <rchristian@ryanchristian.dev>

Author: 3 people

test/router.test.js

@@ -41,7 +41,6 @@ describe('Router', () => {
 		history.replaceState(null, null, '/');
 	});
 
-
 	it('should throw a clear error if the LocationProvider is missing', () => {
 		const Home = () => <h1>Home</h1>;
 
@@ -611,16 +610,14 @@ describe('Router', () => {
 			});
 		}
 
-		// TODO: These tests are rather flakey, for some reason the additional handler
-		// occasionally isn't running prior browser actually navigates away.
+		// TODO: Need a better way to test these. We're currently racing the browser and trying to observe
+		// the navigation event after is has been ignored by the router, but before any navigation occurs,
+		// which has been incredibly flakey. Not to mention, wtr runs in an iframe so `_top` and `_parent`
+		// wouldn't act as expected either (cheers to @sbesh91 for that).
+		//
+		// For now, we can skip, though it'd be good to get a better option in place.
 		for (const target of shouldNavigate) {
-			it(`should allow default browser navigation for links with ${getName(target)}`, async () => {
-				// Currently cross-window navigations, (e.g., `target="_blank"`), do not trigger a
-				// `navigate` event, which makes this difficult to observe. Per the spec, however, this
-				// might be a bug in Chrome's implementation:
-				// https://github.com/WICG/navigation-api?tab=readme-ov-file#restrictions-on-firing-canceling-and-responding
-				if (target === '_blank' || target === '_BLANK' || target === 'custom') return;
-
+			it.skip(`should allow default browser navigation for links with ${getName(target)}`, async () => {
 				scratch.querySelector(`#${createId(target)}`).click();
 				await sleep(1);
 				expect(triedToNavigate).to.be.true;
@@ -989,12 +986,12 @@ describe('Router', () => {
 
 		expect(loc).to.deep.include({ url: '/foo', path: '/foo', searchParams: {} });
 
-		navigation.back();
+		await navigation.back().finished;
 		await sleep(10);
 
 		expect(loc).to.deep.include({ url: '/', path: '/', searchParams: {} });
 
-		navigation.forward();
+		await navigation.forward().finished;
 		await sleep(10);
 
 		expect(loc).to.deep.include({ url: '/foo', path: '/foo', searchParams: {} });