fix(workers): distribute only tests matching grep

docs/parallel.md

@@ -20,7 +20,7 @@ For anything more specific — your own grouping, a config per group, several br
 npx codeceptjs run-workers 4
 ```
 
-Steps are not streamed to the console in this mode — output from separate threads can't be interleaved cleanly. While workers run, CodeceptJS sets `process.env.RUNS_WITH_WORKERS=true`, so plugins and helpers can branch on it. All `run` options work here too: `--grep "@smoke"`, `-c codecept.conf.js`, `--debug`, and the rest.
+Steps are not streamed to the console in this mode — output from separate threads can't be interleaved cleanly. While workers run, CodeceptJS sets `process.env.RUNS_WITH_WORKERS=true`, so plugins and helpers can branch on it. All `run` options work here too: `--grep "@smoke"`, `-c codecept.conf.js`, `--debug`, and the rest. With `--grep`, only matching tests are spread across workers, so a narrow pattern may start fewer workers than requested.
 
 By default, workers are created with a staggered delay of 200ms to prevent CPU spikes and stagger browser initializations. You can adjust this via `workerInitializationDelay` in your configuration.
 

lib/workers.js

@@ -57,6 +57,17 @@ const populateGroups = numberOfWorkers => {
   return groups
 }
 
+const matchesGrep = (mocha, test) => {
+  const { grep, invert } = mocha.options
+  if (!grep) return true
+  return grep.test(test.fullTitle()) !== Boolean(invert)
+}
+
+const withoutEmptyGroups = groups => {
+  const nonEmpty = groups.filter(group => group.length)
+  return nonEmpty.length ? nonEmpty : groups.slice(0, 1)
+}
+
 const createWorker = (workerObject, isPoolMode = false) => {
   const worker = new Worker(pathToWorker, {
     workerData: {
@@ -345,7 +356,8 @@ class Workers extends EventEmitter {
       if (config.by === 'pool') {
         this.createTestPool(numberOfWorkers)
       } else {
-        this.testGroups = config.by === 'suite' ? await this.createGroupsOfSuites(numberOfWorkers) : await this.createGroupsOfTests(numberOfWorkers)
+        const groups = config.by === 'suite' ? await this.createGroupsOfSuites(numberOfWorkers) : await this.createGroupsOfTests(numberOfWorkers)
+        this.testGroups = withoutEmptyGroups(groups)
       }
     }
   }
@@ -379,13 +391,16 @@ class Workers extends EventEmitter {
     const groups = populateGroups(numberOfWorkers)
     let groupCounter = 0
 
+    const tests = []
     mocha.suite.eachTest(test => {
-      const i = groupCounter % groups.length
-      if (test) {
-        groups[i].push(test.uid)
-        groupCounter++
-      }
+      if (test) tests.push(test)
     })
+    const selected = tests.filter(test => matchesGrep(mocha, test))
+
+    for (const test of selected.length ? selected : tests) {
+      groups[groupCounter % groups.length].push(test.uid)
+      groupCounter++
+    }
 
     // Clean up after collecting test UIDs
     mocha.unloadFiles()
@@ -464,14 +479,13 @@ class Workers extends EventEmitter {
     mocha.files = files
     await loadTests(mocha)
 
-    mocha.suite.suites.forEach(suite => {
+    const suites = mocha.suite.suites.map(suite => suite.tests.filter(test => test))
+    const selected = suites.map(tests => tests.filter(test => matchesGrep(mocha, test))).filter(tests => tests.length)
+
+    for (const tests of selected.length ? selected : suites) {
       const i = indexOfSmallestElement(groups)
-      suite.tests.forEach(test => {
-        if (test) {
-          groups[i].push(test.uid)
-        }
-      })
-    })
+      tests.forEach(test => groups[i].push(test.uid))
+    }
 
     // Clean up after collecting test UIDs
     mocha.unloadFiles()

test/runner/run_workers_test.js

@@ -95,6 +95,38 @@ describe('CodeceptJS Workers Runner', function () {
     })
   })
 
+  it('should distribute only tests matching grep', function (done) {
+    exec(`${codecept_run} 3 --grep "grep"`, (err, stdout) => {
+      expect(stdout).toContain('Worker 1: 1 test')
+      expect(stdout).toContain('Worker 2: 1 test')
+      expect(stdout).not.toContain('Worker 3:')
+      expect(stdout).not.toContain('No tests found by pattern')
+      expect(stdout).toContain('OK  | 2 passed')
+      expect(err).toEqual(null)
+      done()
+    })
+  })
+
+  it('should distribute only tests not matching inverted grep', function (done) {
+    exec(`${codecept_run} 2 --grep "Workers" --invert`, (err, stdout) => {
+      expect(stdout).toContain('Worker 1: 1 test')
+      expect(stdout).toContain('Worker 2: 1 test')
+      expect(stdout).toContain('From worker @1_grep print message 1')
+      expect(stdout).toContain('From worker @2_grep print message 2')
+      expect(stdout).toContain('OK  | 2 passed')
+      expect(err).toEqual(null)
+      done()
+    })
+  })
+
+  it('should suggest tests when grep matches nothing', function (done) {
+    exec(`${codecept_run} 2 --grep "nonexistent"`, (err, stdout) => {
+      expect(stdout).toContain('No tests found by pattern: /nonexistent/')
+      expect(stdout).toContain('OK  | 0 passed')
+      done()
+    })
+  })
+
   it('should use suites', function (done) {
     if (!semver.satisfies(process.version, '>=11.7.0')) this.skip('not for node version')
     exec(`${codecept_run} 2 --suites`, (err, stdout) => {