JSON test report should include `coverageMap`

[rlaferla]

Describe the bug

vitest should include the coverage map in the coverage report but instead puts them in separate files.

The report should contain a key for the coverage map

e.g.

vitest run --coverage --outputFile=report.json --reporter=json

"coverageMap": {
  "/src/test.ts": {
    "path": "/src/test.ts",
    "statementMap": {
       "0": {
         "start": {
           "line": 1,
           "column": 0
         },
         "end": {
           "line": 1,
           "column": 44
         }
       }
    }
  }
}

Instead it puts the coverage map in a separate file:

coverage/coverage-final.json

Reproduction

If you run:

`% vitest run --coverage --outputFile=report.json --reporter=json

Both of these searches will not return any results:

% grep coverageMap report.json
% grep statementMap report.json

while this will return a result indicating that the json file is the coverage map.

% grep statementMap coverage/coverage-final.json

System Info

System:
    OS: macOS 14.0
    CPU: (8) arm64 Apple M2
    Memory: 685.72 MB / 24.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 18.16.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 9.5.1 - /usr/local/bin/npm
  Browsers:
    Brave Browser: 116.1.57.47
    Chrome: 117.0.5938.149
    Safari: 17.0
  npmPackages:
    @vitest/coverage-v8: ^0.34.6 => 0.34.6 
    vite: ^4.4.11 => 4.4.11 
    vitest: ^0.34.6 => 0.34.6

Used Package Manager

npm

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
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• The provided reproduction is a minimal reproducible example of the bug.

[AriPerkkio]

vitest should include the coverage map in the coverage report but instead puts them in separate files.

I'm not sure if I'm understanding this correctly. The vitest --reporter=json --outputFile=report.json will generate report.json that contains information about the test run. The vitest --coverage.enabled ---coverage.reporter=json will generate a coverage/coverage-final.json which contains information about the code coverage. Do you want coverage report to be included in the test report as well? If so, why? Do other tools do this?

[sheremet-va]

Do other tools do this?

Looks like jest does, but we didn't implement it at the time (since there was no coverage yet):

vitest/packages/vitest/src/node/reporters/json.ts

Line 59 in eac7776

// coverageMap?: CoverageMap | null | undefined

[AriPerkkio]

I can't find any documentation from Jest on this, but it's there on the source code. I guess we can add this to be more compatible with Jest.