Add test for invalid ref in Link

[ijjk]

This makes sure that onMouseEnter triggers prefetching when an invalid ref is returned in a Link

[github-actions]

Stats from current PR

Click to expand stats

	zeit/next.js canary	ijjk/next.js add/more-preload-tests	Change
Build Duration	15.5s	15.3s	-217ms
node_modules Size	39.1 MB	39.1 MB	✓
Total Bundle (main, webpack, commons) Size	209 kB	209 kB	✓
Total Bundle (main, webpack, commons) gzip Size	68.4 kB	68.4 kB	✓
Client _app Size	2.6 kB	2.6 kB	✓
Client _app gzip Size	1.07 kB	1.07 kB	✓
Client _error Size	8.19 kB	8.19 kB	✓
Client _error gzip Size	3.12 kB	3.12 kB	✓
Client pages/index Size	288 B	288 B	✓
Client pages/index gzip Size	222 B	222 B	✓
Client pages/link Size	4.83 kB	4.83 kB	✓
Client pages/link gzip Size	2.11 kB	2.11 kB	✓
Client pages/routerDirect Size	411 B	411 B	✓
Client pages/routerDirect gzip Size	296 B	296 B	✓
Client pages/withRouter Size	393 B	393 B	✓
Client pages/withRouter gzip Size	280 B	280 B	✓
Client main Size	23.3 kB	23.3 kB	✓
Client main gzip Size	7.63 kB	7.63 kB	✓
Client commons Size	183 kB	183 kB	✓
Client commons gzip Size	59.4 kB	59.4 kB	✓
Client webpack Size	1.49 kB	1.49 kB	✓
Client webpack gzip Size	769 B	769 B	✓
Base Rendered Size	1.34 kB	1.34 kB	✓
Build Dir Size	801 kB	801 kB	✓

Click to expand serverless stats

	zeit/next.js canary	ijjk/next.js add/more-preload-tests	Change
Build Duration	16.6s	16.4s	-239ms
node_modules Size	39.1 MB	39.1 MB	✓
Total Bundle (main, webpack, commons) Size	209 kB	209 kB	✓
Total Bundle (main, webpack, commons) gzip Size	68.4 kB	68.4 kB	✓
Client _app Size	2.6 kB	2.6 kB	✓
Client _app gzip Size	1.07 kB	1.07 kB	✓
Client _error Size	8.19 kB	8.19 kB	✓
Client _error gzip Size	3.12 kB	3.12 kB	✓
Client pages/index Size	288 B	288 B	✓
Client pages/index gzip Size	222 B	222 B	✓
Client pages/link Size	4.83 kB	4.83 kB	✓
Client pages/link gzip Size	2.11 kB	2.11 kB	✓
Client pages/routerDirect Size	411 B	411 B	✓
Client pages/routerDirect gzip Size	296 B	296 B	✓
Client pages/withRouter Size	393 B	393 B	✓
Client pages/withRouter gzip Size	280 B	280 B	✓
Client main Size	23.3 kB	23.3 kB	✓
Client main gzip Size	7.63 kB	7.63 kB	✓
Client commons Size	183 kB	183 kB	✓
Client commons gzip Size	59.4 kB	59.4 kB	✓
Client webpack Size	1.49 kB	1.49 kB	✓
Client webpack gzip Size	769 B	769 B	✓
Serverless pages/link Size	342 kB	342 kB	✓
Serverless pages/link gzip Size	88.8 kB	88.8 kB	✓
Serverless pages/index Size	333 kB	333 kB	✓
Serverless pages/index gzip Size	86.3 kB	86.3 kB	✓
Serverless pages/_error Size	334 kB	334 kB	✓
Serverless pages/_error gzip Size	86.1 kB	86.1 kB	✓
Serverless pages/routerDirect Size	333 kB	333 kB	✓
Serverless pages/routerDirect gzip Size	86.4 kB	86.4 kB	⚠️ +3 B
Serverless pages/withRouter Size	334 kB	334 kB	✓
Serverless pages/withRouter gzip Size	86.5 kB	86.5 kB	✓
Build Dir Size	2.37 MB	2.37 MB	✓