Installed the Stryker Mutator and ran the default mutation test (Dynamic tool)

[HeidiTao]

Followed the quick start guide for Stryker Mutator, a dynamic analysis tool that performs mutation tests.

Concrete evidence of tool installation

1. Running npm init stryker in terminal:

2. Stryker in packag.json (file not part of this PR due to being in gitignore)

3. Config file generated after initialization

4. node_modules folder generated
   

Artifacts that demonstrate tool running on repository

[coveralls]

Pull Request Test Coverage Report for Build 11494755977

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.003%) to 82.667%

---

Files with Coverage Reduction	New Missed Lines	%
src/meta/errors.js	1	83.72%

Totals
Change from base Build 11492017180:	0.003%
Covered Lines:	22341
Relevant Lines:	25603

---

💛 - Coveralls

[HeidiTao]

Commented out the illegal return line in file src/cli/index.js;
Re-ran Stryker test with the following output:

[HeidiTao]

After ignoring the files under build, less files were being passed into the list of possible files being mutated.

New error is TypeError: Cannot set properties of undefined (setting 'require')

[sherryzhuge1]

Looks good!

[John-Crawshaw]

lgtm

[Victor-Crawshaw]

Looks good

[alx-zhu]

Looks good!

[HeidiTao]

I've tried more edits in the config and error-reported files, but the npx stryker run command still returns errors. According to a TA at Office Hour, this PR is sufficient for checkpoint.

[HeidiTao]

A few additional attempts were made to run Stryker without error.

• From the undefined require error, I tried using import and export to replace the require function. However, since most of the NodeBB code still uses CommonJS which relies on require, I changed them back.
• Since Stryker requires all unit tests to pass before it runs tests with its mutants, all the failed test cases are stopping Stryker's initial run to be successful. For example,
  
  
• I am in the progress of manually commenting out the test cases that were reporting errors. Since the total number of test cases keeps increasing after failed ones are commented out, I am also simultaneously searching for other more efficient ways to solve this problem. (e.g., Mocha test run total number increased to 1682)