fix: do not override NODE_V8_COVERAGE if set (#70)

Author: Kilian Ciuffolo

lib/parse-args.js

@@ -62,7 +62,8 @@ function buildYargs (withCommands = false) {
       type: 'boolean'
     })
     .option('temp-directory', {
-      describe: 'directory V8 coverage data is written to and read from'
+      describe: 'directory V8 coverage data is written to and read from',
+      default: process.env.NODE_V8_COVERAGE
     })
     .option('resolve', {
       default: '',

test/integration.js

@@ -26,6 +26,21 @@ describe('c8', () => {
     output.toString('utf8').should.matchSnapshot()
   })
 
+  it('supports exeternally set NODE_V8_COVERAGE', () => {
+    const { output } = spawnSync(nodePath, [
+      c8Path,
+      '--exclude="test/*.js"',
+      '--clean=false',
+      nodePath,
+      require.resolve('./fixtures/normal')
+    ], {
+      env: {
+        'NODE_V8_COVERAGE': './coverage/tmp_'
+      }
+    })
+    output.toString('utf8').should.matchSnapshot()
+  })
+
   it('merges reports from subprocesses together', () => {
     const { output } = spawnSync(nodePath, [
       c8Path,

test/integration.js.snap

@@ -200,3 +200,36 @@ All files   |    70.37 |    66.67 |       60 |    70.37 |                   |
 ------------|----------|----------|----------|----------|-------------------|
 ,"
 `;
+
+exports[`c8 supports exeternally set NODE_V8_COVERAGE 1`] = `
+",hey
+i am a line of code
+what
+hey
+what
+hey
+what
+hey
+-----------------------|----------|----------|----------|----------|-------------------|
+File                   |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
+-----------------------|----------|----------|----------|----------|-------------------|
+All files              |    89.77 |    74.21 |    88.14 |    89.77 |                   |
+ bin                   |    69.81 |    64.29 |    92.86 |    69.81 |                   |
+  c8.js                |    69.81 |    64.29 |    92.86 |    69.81 |... 49,50,51,52,53 |
+ lib                   |    93.33 |    72.73 |      100 |    93.33 |                   |
+  is-cjs-esm-bridge.js |       90 |       70 |      100 |       90 |                 9 |
+  parse-args.js        |    97.69 |    47.83 |      100 |    97.69 |        99,107,108 |
+  report.js            |    90.29 |    83.64 |      100 |    90.29 |... 40,160,161,162 |
+ lib/commands          |    89.53 |    85.71 |       75 |    89.53 |                   |
+  check-coverage.js    |    88.33 |    93.33 |       75 |    88.33 |... 46,57,58,59,60 |
+  report.js            |    92.31 |    76.92 |       75 |    92.31 |              9,10 |
+ test/fixtures         |    89.19 |    94.44 |       70 |    89.19 |                   |
+  async.js             |      100 |      100 |      100 |      100 |                   |
+  export.mjs           |    71.43 |      100 |       50 |    71.43 |               2,3 |
+  import.mjs           |      100 |      100 |      100 |      100 |                   |
+  multiple-spawn.js    |      100 |      100 |      100 |      100 |                   |
+  normal.js            |       75 |       75 |    33.33 |       75 | 14,15,16,18,19,20 |
+  subprocess.js        |      100 |      100 |      100 |      100 |                   |
+-----------------------|----------|----------|----------|----------|-------------------|
+,"
+`;

test/parse-args.js

@@ -21,6 +21,18 @@ describe('parse-args', () => {
       const argv = buildYargs().parse(hideInstrumenteeArgs())
       const instrumenteeArgs = hideInstrumenterArgs(argv)
       instrumenteeArgs.should.eql(['my-app', '--help'])
+      argv.tempDirectory.endsWith('/coverage/tmp').should.be.equal(true)
+    })
+  })
+
+  describe('with NODE_V8_COVERAGE already set', () => {
+    it('should not override it', () => {
+      const NODE_V8_COVERAGE = process.env.NODE_V8_COVERAGE
+      process.env.NODE_V8_COVERAGE = './coverage/tmp_'
+      process.argv = ['node', 'c8', '--foo=99', 'my-app', '--help']
+      const argv = buildYargs().parse(hideInstrumenteeArgs())
+      argv.tempDirectory.endsWith('/coverage/tmp_').should.be.equal(true)
+      process.env.NODE_V8_COVERAGE = NODE_V8_COVERAGE
     })
   })
 })