Online playground (#102)

[LeaVerou]

• Run into issues with Prism Live CSS
• Error with failing tests, ping @DmitrySharabin as the trace goes inside some of your code!

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[DmitrySharabin]

• Error with failing tests, ping @DmitrySharabin as the trace goes inside some of your code!

It's the last test with expect: undefined that causes it. The issue is related to the way we stringify undefined. Our code expects it to be a string (well, it should, according to its name and all the rest of the code), but it's always undefined:

htest/src/classes/TestResult.js

Line 301 in bd8cb0e

let expectString = stringify(expect);

htest/src/util.js

Line 146 in bd8cb0e

export function stringify (obj, options = {}) {

It seems to me we might have the same issue with null. I wonder if we should do the same as we already do with NaN (stringify it to "NaN") and return "undefined" and "null"?

If we don't stringify undefined correctly, we'll get incorrect output as well (see the last test where there's no expected value):

[LeaVerou]

Yes, stringifying to "undefined" seems reasonable. Same for null.

[DmitrySharabin]

Yes, stringifying to "undefined" seems reasonable. Same for null.

Here is the fix: #104