Always set window.event in test environment

[gaearon]

To avoid future surprises and confusion. Let's just do it everywhere.

I'm not sure this is exactly accurate and matches how the browser does it. Probably not. But close enough?

[sizebot]

Comparing: ad8211d...f55f74d

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.min.js	=	122.48 kB	122.48 kB	=	39.45 kB	39.45 kB
oss-experimental/react-dom/cjs/react-dom.production.min.js	=	129.06 kB	129.06 kB	=	41.50 kB	41.50 kB
facebook-www/ReactDOM-prod.classic.js	=	406.84 kB	406.84 kB	=	75.42 kB	75.42 kB
facebook-www/ReactDOM-prod.modern.js	=	395.19 kB	395.19 kB	=	73.54 kB	73.54 kB
facebook-www/ReactDOMForked-prod.classic.js	=	406.85 kB	406.85 kB	=	75.42 kB	75.42 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against f55f74d

[acdlite]

Hmm. Will most users run their tests in an environment with window.event? What does JSDOM do? How will React Testing Library work?

Maybe we should warn if it's undefined? Though then we need some guidance for fixing it.

[gaearon]

Hmm yeah good point. The answer is I have no idea. I'll ask Twitter.

[gaearon]

Maybe we should warn if it's undefined?

How would you know you're in an event though?

What does JSDOM do?

Seems like it doesn't do anything, as it's sort of a legacy property. At least our version doesn't.

How will React Testing Library work?

I think RTL could do something like this as part of its setup. Or in its fireEvent wrapper.

[crypt096]

Please resolve conflicts.