feat(server): allow 'exit' listeners to set exit code

lib/server.js

@@ -142,6 +142,35 @@ class Server extends KarmaEventEmitter {
     return this._fileList ? this._fileList.changeFile(path) : Promise.resolve()
   }
 
+  emitExitAsync (code) {
+    const name = 'exit'
+    let pending = this.listeners(name).length
+    const deferred = helper.defer()
+
+    function resolve () {
+      deferred.resolve(code)
+    }
+
+    try {
+      this.emit(name, (newCode) => {
+        if (newCode && typeof newCode === 'number') {
+          // Only update code if it is given and not zero
+          code = newCode
+        }
+        if (!--pending) {
+          resolve()
+        }
+      })
+
+      if (!pending) {
+        resolve()
+      }
+    } catch (err) {
+      deferred.reject(err)
+    }
+    return deferred.promise
+  }
+
   async _start (config, launcher, preprocess, fileList, capturedBrowsers, executor, done) {
     if (config.detached) {
       this._detach(config, done)
@@ -296,7 +325,8 @@ class Server extends KarmaEventEmitter {
 
     this.on('stop', function (done) {
       this.log.debug('Received stop event, exiting.')
-      return disconnectBrowsers().then(done)
+      disconnectBrowsers()
+      done()
     })
 
     if (config.singleRun) {
@@ -354,28 +384,29 @@ class Server extends KarmaEventEmitter {
         }
       })
 
-      let removeAllListenersDone = false
-      const removeAllListeners = () => {
-        if (removeAllListenersDone) {
-          return
+      this.emitExitAsync(code).catch((err) => {
+        this.log.error('Error while calling exit event listeners\n' + err.stack || err)
+        return 1
+      }).then((code) => {
+        socketServer.sockets.removeAllListeners()
+        socketServer.close()
+
+        let removeAllListenersDone = false
+        const removeAllListeners = () => {
+          if (removeAllListenersDone) {
+            return
+          }
+          removeAllListenersDone = true
+          webServer.removeAllListeners()
+          processWrapper.removeAllListeners()
+          done(code || 0)
         }
-        removeAllListenersDone = true
-        webServer.removeAllListeners()
-        processWrapper.removeAllListeners()
-        done(code || 0)
-      }
 
-      return this.emitAsync('exit').then(() => {
-        return new Promise((resolve, reject) => {
-          socketServer.sockets.removeAllListeners()
-          socketServer.close()
-          const closeTimeout = setTimeout(removeAllListeners, webServerCloseTimeout)
+        const closeTimeout = setTimeout(removeAllListeners, webServerCloseTimeout)
 
-          webServer.close(() => {
-            clearTimeout(closeTimeout)
-            removeAllListeners()
-            resolve()
-          })
+        webServer.close(() => {
+          clearTimeout(closeTimeout)
+          removeAllListeners()
         })
       })
     }

test/unit/server.spec.js

@@ -306,6 +306,110 @@ describe('server', () => {
         expect(await exitCode()).to.have.equal(15)
       })
 
+      it('given on run_complete with exit event listener (15)', async () => {
+        mockProcess(process)
+
+        await server._start(mockConfig, mockLauncher, null, mockFileList, browserCollection, mockExecutor, (exitCode) => {
+          resolveExitCode(exitCode)
+        })
+
+        // last non-zero exit code will be taken
+        server.on('exit', (done) => {
+          setTimeout(() => done(30))
+        })
+        server.on('exit', (done) => {
+          setTimeout(() => done(15))
+        })
+        server.on('exit', (done) => {
+          setTimeout(() => done(0))
+        })
+
+        // Provided run_complete exitCode will be overridden by exit listeners
+        server.emit('run_complete', browserCollection, { exitCode: 5 })
+
+        function mockProcess (process) {
+          sinon.stub(process, 'kill').callsFake((pid, ev) => process.emit(ev))
+        }
+        expect(await exitCode()).to.have.equal(15)
+      })
+
+      it('given on run_complete with exit event listener (0)', async () => {
+        mockProcess(process)
+
+        await server._start(mockConfig, mockLauncher, null, mockFileList, browserCollection, mockExecutor, (exitCode) => {
+          resolveExitCode(exitCode)
+        })
+
+        // exit listeners can't set exit code back to 0
+        server.on('exit', (done) => {
+          setTimeout(() => done(0))
+        })
+
+        server.emit('run_complete', browserCollection, { exitCode: 15 })
+
+        function mockProcess (process) {
+          sinon.stub(process, 'kill').callsFake((pid, ev) => process.emit(ev))
+        }
+        expect(await exitCode()).to.have.equal(15)
+      })
+
+      it('1 on run_complete with exit event listener throws', async () => {
+        mockProcess(process)
+
+        await server._start(mockConfig, mockLauncher, null, mockFileList, browserCollection, mockExecutor, (exitCode) => {
+          resolveExitCode(exitCode)
+        })
+
+        server.on('exit', (done) => {
+          throw new Error('async error from exit event listener')
+        })
+
+        server.emit('run_complete', browserCollection, { exitCode: 0 })
+
+        function mockProcess (process) {
+          sinon.stub(process, 'kill').callsFake((pid, ev) => process.emit(ev))
+        }
+        expect(await exitCode()).to.have.equal(1)
+      })
+
+      it('1 on run_complete with exit event listener rejects', async () => {
+        mockProcess(process)
+
+        await server._start(mockConfig, mockLauncher, null, mockFileList, browserCollection, mockExecutor, (exitCode) => {
+          resolveExitCode(exitCode)
+        })
+
+        function onExit (done) {
+          // Need to remove listener to prevent endless loop via unhandledRejection handler
+          // which again calls disconnectBrowsers to fire the 'exit' event
+          server.off('exit', onExit)
+          return Promise.reject(new Error('async error from exit event listener'))
+        }
+        server.on('exit', onExit)
+
+        server.emit('run_complete', browserCollection, { exitCode: 0 })
+
+        function mockProcess (process) {
+          sinon.stub(process, 'kill').callsFake((pid, ev) => process.emit(ev))
+        }
+        expect(await exitCode()).to.have.equal(1)
+      })
+
+      it('0 on server stop', async () => {
+        mockProcess(process)
+
+        await server._start(mockConfig, mockLauncher, null, mockFileList, browserCollection, mockExecutor, (exitCode) => {
+          resolveExitCode(exitCode)
+        })
+
+        server.stop()
+
+        function mockProcess (process) {
+          sinon.stub(process, 'kill').callsFake((pid, ev) => process.emit(ev))
+        }
+        expect(await exitCode()).to.have.equal(0)
+      })
+
       it('1 on browser_process_failure (singleRunBrowserNotCaptured)', async () => {
         mockProcess(process)