Add more complete unit tests

[erickzhao]

What are you trying to accomplish with this PR?

Adds more complete unit tests, including the missing logger and install files. Also fixed a bug in /lib/logger.js not accepting multiple parameters.

Jest coverage output

-------------------|----------|----------|----------|----------|-------------------|
File               |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-------------------|----------|----------|----------|----------|-------------------|
All files          |    95.51 |    93.55 |    86.67 |    95.45 |                   |
 config.js         |      100 |      100 |      100 |      100 |                   |
 install.js        |      100 |      100 |      100 |      100 |                   |
 logger.js         |      100 |      100 |      100 |      100 |                   |
 run-executable.js |     87.5 |       50 |    66.67 |     87.5 |          30,34,39 |
 themekit.js       |      100 |      100 |      100 |      100 |                   |
 utils.js          |    94.74 |       90 |      100 |    94.44 |                16 |
-------------------|----------|----------|----------|----------|-------------------|

Checklist

For contributors:

• I have updated the documentation in the README file to reflect these changes, if applicable.

For maintainers:

• I have 🎩'd these changes.
• I have bumped the package.json version in a separate PR, if applicable.

Considerations:

• Changes may require updates to the Slate docs or the @shopify/slate-tools package.

[t-kelly]

Nice work @erickzhao! Small stuff to look at.

[t-kelly]

Minor, but could be:

expect(config.binName).toBe('theme.exe');

[t-kelly]

Wouldn't binWrapperObject throw a ReferenceError at this point since const variables are not hoisted and is binWrapperObject is declared below?

Or I guess it is not referenced until this callback is called... in which case binWrapperObject is declared in the parent scope? 🤔

[erickzhao]

Honestly not sure at all. I just tried stuff until it worked for this one, which was tricky since I needed the mutually recursive definitions. In any case, the mock seems to behave as expected. 🤷🏻‍♂️

[t-kelly]

Nice use of mockImplementationOnce() 👍

[t-kelly]

Do you mean to have logger() here? This test is identical to the one on line 52.

[erickzhao]

@t-kelly made some small fixes! :) Tests still passing.