Add support for --coverage-map=<module>

bin/jack.js

@@ -258,6 +258,24 @@ Much more documentation available at: https://www.node-tap.org/
                   coverage entirely with --no-coverage.`,
   }),
 
+  'coverage-map': opt({
+    short: 'M',
+    hint: 'module',
+    description: `Provide a path to a node module that exports a single
+                  function.  That function takes a test file as an argument,
+                  and returns an array of files to instrument with coverage
+                  when that file is run.
+
+                  This is useful in cases where a unit test should cover
+                  a single portion of the system under test.
+
+                  Return 'null' to not cover any files by this test.
+
+                  Return an empty array [] to cover the set that nyc would
+                  pull in by default.  Ie, returning [] is equivalent to not
+                  using a coverage map at all.`,
+  }),
+
   coverage: flag({
     default: true,
     short: 'cov',

bin/run.js

@@ -57,7 +57,7 @@ const defaultFiles = options => new Promise((res, rej) => {
         const files = []
         finder.on('file', addFile(files))
         finder.on('end', () => res(files))
-        finder.on('error', er => rej(er))
+        finder.on('error', /* istanbul ignore next */ er => rej(er))
       })
     }))).then(a => res(a.reduce((a, i) => a.concat(i), []))).catch(rej)
   })
@@ -139,7 +139,10 @@ const main = async options => {
   try {
     if (options._.length === 0 && isTTY)
       options._.push.apply(options._, await defaultFiles(options))
-  } catch (er) {
+  } /* istanbul ignore next */ catch (er) /* istanbul ignore next */ {
+    // This gets tested on Mac, but not Linux/travis, and is
+    // somewhat challenging to do in a cross-platform way.
+    /* istanbul ignore next */
     return require('../lib/tap.js').threw(er)
   }
 
@@ -231,7 +234,11 @@ const pipeToCoveralls = async options => {
 
 /* istanbul ignore next */
 const respawnWithCoverage = options => {
-  runNyc([], [
+  // If we have a coverage map, then include nothing by default here.
+  runNyc(options['coverage-map'] ? [
+    '--include=',
+    '--no-exclude-after-remap',
+  ] : [], [
     '--',
     node,
     ...process.execArgv,
@@ -431,6 +438,17 @@ const getEnv = options => options['test-env'].reduce((env, kv) => {
   return env
 }, {...process.env})
 
+// the test that checks this escapes from NYC, so it'll never show up
+/* istanbul ignore next */
+const coverageMapOverride = (env, file, coverageMap) => {
+  if (coverageMap) {
+    /* istanbul ignore next */
+    env.NYC_CONFIG_OVERRIDE = JSON.stringify({
+      include: coverageMap(file) || ''
+    })
+  }
+}
+
 const runAllFiles = (options, saved, tap) => {
   let doStdin = false
   let parallelOk = Object.create(null)
@@ -456,9 +474,15 @@ const runAllFiles = (options, saved, tap) => {
     tap.fail('no tests specified')
   }
 
+  /* istanbul ignore next */
   const processDB = options.coverage && process.env.NYC_CONFIG
     ? new ProcessDB() : null
 
+  /* istanbul ignore next */
+  const coverageMap = options['coverage-map']
+    ? require(path.resolve(options['coverage-map']))
+    : null
+
   for (let i = 0; i < options.files.length; i++) {
     const file = options.files[i]
 
@@ -484,6 +508,8 @@ const runAllFiles = (options, saved, tap) => {
     } else {
       const opt = { env, file, processDB }
 
+      coverageMapOverride(env, file, coverageMap)
+
       if (options.timeout)
         opt.timeout = options.timeout * 1000
 

coverage-map.js

@@ -0,0 +1,22 @@
+const glob = require('glob')
+const path = require('path')
+module.exports = t => {
+  const parts = path.relative(process.cwd(), path.resolve(t)).split(/\\|\//)
+  const unit = path.basename(parts[1], '.js')
+  if (unit === 'run')
+    return glob.sync('bin/*.js')
+  if (unit === 'coverage-map')
+    return [ path.basename(__filename) ]
+  const cov = glob.sync(`lib/${unit}.js`)
+  if (!cov.length)
+    return null
+  return cov
+}
+
+/* istanbul ignore next */
+if (module === require.main) {
+  const tests = process.argv.length > 2
+    ? process.argv.slice(2)
+    : glob.sync('test/**/*.js')
+  console.log(tests.map(t => [t, module.exports(t)]))
+}

docs/cli/index.md

@@ -154,6 +154,21 @@ Code Coverage Options:
                          coverage checking with --no-check-coverage, or disable
                          coverage entirely with --no-coverage.
 
+  -M<module> --coverage-map=<module>
+                         Provide a path to a node module that exports a single
+                         function. That function takes a test file as an
+                         argument, and returns an array of files to instrument
+                         with coverage when that file is run.
+
+                         This is useful in cases where a unit test should cover
+                         a single portion of the system under test.
+
+                         Return 'null' to not cover any files by this test.
+
+                         Return an empty array [] to cover the set that nyc
+                         would pull in by default. Ie, returning [] is
+                         equivalent to not using a coverage map at all.
+
   -cov --coverage        Capture coverage information using 'nyc' This is
                          enabled by default.
 

lib/base.js

@@ -67,7 +67,8 @@ class Base extends MiniPass {
     this.output = ''
     this.results = null
     this.bailedOut = false
-    this.childId = +ownOrEnv(options, 'childId', 'TAP_CHILD_ID') || 0
+    this.childId = +ownOrEnv(options, 'childId', 'TAP_CHILD_ID')
+      || /* istanbul ignore next */ 0
     const skip = ownOr(options, 'skip', false)
     const todo = ownOr(options, 'todo', false)
     if (skip || todo)

lib/spawn.js

@@ -35,7 +35,9 @@ class Spawn extends Base {
       options.env = process.env
     this.env = {
       ...(options.env),
-      TAP_CHILD_ID: options.childId || options.env.TAP_CHILD_ID || this.childId,
+      TAP_CHILD_ID: options.childId
+        || options.env.TAP_CHILD_ID
+        || /* istanbul ignore next */ 0,
       TAP: '1',
       TAP_BAIL: this.bail ? '1' : '0',
     }

lib/tap.js

@@ -49,7 +49,8 @@ class TAP extends Test {
   constructor (options) {
     super(options)
     this.runOnly = process.env.TAP_ONLY === '1'
-    this.childId = +process.env.TAP_CHILD_ID || 0
+    this.childId = +process.env.TAP_CHILD_ID
+      || /* istanbul ignore next */ 0
     this.start = Date.now()
     this[_didPipe] = false
   }

lib/test.js

@@ -102,7 +102,7 @@ class Test extends Base {
   constructor (options) {
     options = options || {}
     super(options)
-    this[_nextChildId] = 0
+    this[_nextChildId] = 1
     this.pushedEnd = false
     this.jobs = ownOr(options, 'jobs', 1)
 

package.json

@@ -31,10 +31,10 @@
     "import-jsx": "^2.0.0",
     "isexe": "^2.0.0",
     "istanbul-lib-processinfo": "^1.0.0",
-    "jackspeak": "^1.3.4",
+    "jackspeak": "^1.3.5",
     "minipass": "^2.3.5",
     "mkdirp": "^0.5.1",
-    "nyc": "^14.0.0",
+    "nyc": "github:isaacs/nyc#conf-override",
     "opener": "^1.5.1",
     "own-or": "^1.0.0",
     "own-or-env": "^1.0.1",
@@ -65,7 +65,7 @@
   "repository": "https://github.com/tapjs/node-tap.git",
   "scripts": {
     "snap": "bash scripts/snap.sh",
-    "test": "node bin/run.js test",
+    "test": "node bin/run.js test -M coverage-map.js",
     "unit": "bash scripts/unit.sh",
     "posttest": "rm -rf cli-tests-*",
     "postunit": "npm run posttest",

scripts/unit.sh

@@ -12,7 +12,7 @@ else
   include=$(echo +(bin|lib)/$1.js)
   if [ -f "$include" ]; then
     set -x
-    node bin/run.js test/${1}* --nyc-arg=--include="$include" -Rterse
+    node bin/run.js test/${1}* --nyc-arg=--include="$include" -Rterse -M coverage-map.js
   else
     set -x
     node bin/run.js test/${1}* --no-cov -Rterse

tap-snapshots/test-run-coverage.js-TAP.test.js

@@ -5,7 +5,31 @@
  * Make sure to inspect the output below.  Do not ignore changes!
  */
 'use strict'
-exports[`test/run/coverage.js TAP generate some coverage > 100 pass 1`] = `
+exports[`test/run/coverage.js TAP borked coverage map means no includes > output 1`] = `
+TAP version 13
+ok 1 - 1.test.js # {time} {
+    ok 1 - should be equal
+    1..1
+    # {time}
+}
+
+ok 2 - 2.test.js # {time} {
+    ok 1 - should be equal
+    1..1
+    # {time}
+}
+
+1..2
+# {time}
+-|-|-|-|-|-|
+File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Lines |
+-|-|-|-|-|-|
+All files | 0 | 0 | 0 | 0 | |
+-|-|-|-|-|-|
+
+`
+
+exports[`test/run/coverage.js TAP generate some coverage > output 1`] = `
 TAP version 13
 ok 1 - 1.test.js # {time} {
     ok 1 - should be equal
@@ -156,3 +180,28 @@ BRH:3
 end_of_record
 
 `
+
+exports[`test/run/coverage.js TAP use a coverage map > output 1`] = `
+TAP version 13
+ok 1 - 1.test.js # {time} {
+    ok 1 - should be equal
+    1..1
+    # {time}
+}
+
+ok 2 - 2.test.js # {time} {
+    ok 1 - should be equal
+    1..1
+    # {time}
+}
+
+1..2
+# {time}
+-|-|-|-|-|-|
+File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Lines |
+-|-|-|-|-|-|
+All files | 75 | 75 | 100 | 75 | |
+ ok.js | 75 | 75 | 100 | 75 | 6 |
+-|-|-|-|-|-|
+
+`

tap-snapshots/test-run-dump-config.js-TAP.test.js

@@ -13,6 +13,7 @@ check-coverage: true
 color: true
 comments: false
 coverage: false
+coverage-map: null
 coverage-report: null
 debug: false
 esm: false
@@ -55,6 +56,7 @@ check-coverage: true
 color: false
 comments: false
 coverage: false
+coverage-map: null
 coverage-report: null
 debug: false
 esm: false
@@ -97,6 +99,7 @@ check-coverage: false
 color: false
 comments: false
 coverage: false
+coverage-map: null
 coverage-report: null
 debug: false
 esm: false
@@ -139,6 +142,7 @@ check-coverage: false
 color: false
 comments: false
 coverage: false
+coverage-map: null
 coverage-report: null
 debug: false
 esm: false
@@ -181,6 +185,7 @@ check-coverage: false
 color: false
 comments: false
 coverage: false
+coverage-map: null
 coverage-report: null
 debug: false
 esm: false
@@ -223,6 +228,7 @@ check-coverage: true
 color: false
 comments: false
 coverage: false
+coverage-map: null
 coverage-report: null
 debug: false
 esm: false
@@ -265,6 +271,7 @@ check-coverage: true
 color: false
 comments: true
 coverage: true
+coverage-map: null
 coverage-report: html
 debug: true
 esm: false
@@ -318,6 +325,7 @@ check-coverage: true
 color: true
 comments: false
 coverage: false
+coverage-map: null
 coverage-report: null
 debug: false
 esm: false

test/coverage-map.js

@@ -0,0 +1,10 @@
+const t = require('../')
+const coverageMap = require('../coverage-map.js')
+t.strictSame(coverageMap('test/coverage-map.js'), ['coverage-map.js'])
+t.strictSame(coverageMap('test/run/xyz.js'), [
+  'bin/jack.js',
+  'bin/jsx.js',
+  'bin/run.js'
+])
+t.strictSame(coverageMap('test/glorp.js'), null)
+t.strictSame(coverageMap('test/test.js'), ['lib/test.js'])