chore(ci): fix BrowserStack timeouts (#3484)

Assuming that the issue is concurrent jobs attempting to interact with BrowserStack using the same build ID, this solution attempts to solve it by only interacting with BrowserStack in one of the jobs.

Updated build definition:

- runs complete build on the latest Node
- runs simplified build (without commit validation, lint, test:client and test:integration) on earlier versions on Node

It is not very valuable to run omitted test suits multiple times as they supposed to catch issues, which are usually Node-independent: client code fails in some browsers and API breaking changes, which will affect popular Karma plugins.

Fixes #3468

.travis.yml

@@ -1,15 +1,37 @@
 os: linux
 dist: xenial
 language: node_js
-node_js:
-  - 10
-  - 12
 
 jobs:
   include:
-    - name: "Lint code and commit message format"
-      node_js: "10"
-      env: VALIDATE_COMMIT_MSG=true LINT=true
+    - node_js: "10"
+      script:
+        - npm run init
+        - npm run build
+        - npm run test:unit
+        - npm run test:e2e
+
+    - node_js: "12"
+      script:
+        - npm run init
+        - echo "TRAVIS_COMMIT $TRAVIS_COMMIT"
+        - echo "TRAVIS_PULL_REQUEST_SHA $TRAVIS_PULL_REQUEST_SHA"
+        - COMMIT_TO_VALIDATE=${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT}
+        - echo "COMMIT_TO_VALIDATE $COMMIT_TO_VALIDATE"
+        - ./scripts/validate-commit-msg.sh $COMMIT_TO_VALIDATE
+        - npm run lint
+        - npm run build
+        - npm run test:unit
+        - npm run test:e2e
+        - npm run test:client
+        - npm run test:integration
+
+      after_success:
+        # run automated release process with semantic-release
+        - echo "TRAVIS_BRANCH=$TRAVIS_BRANCH, TRAVIS_EVENT_TYPE=$TRAVIS_EVENT_TYPE
+        - if [[ "$TRAVIS_BRANCH" == "master" && "$TRAVIS_EVENT_TYPE" == "push" ]]; then
+            npm run semantic-release;
+          fi;
 
 before_install:
   - npm config set loglevel warn
@@ -19,22 +41,3 @@ addons:
 
 services:
   - xvfb
-
-before_script:
-  - npm run init
-  - echo "TRAVIS_COMMIT $TRAVIS_COMMIT"
-  - echo "TRAVIS_PULL_REQUEST_SHA $TRAVIS_PULL_REQUEST_SHA"
-  - COMMIT_TO_VALIDATE=${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT}
-  - echo "COMMIT_TO_VALIDATE $COMMIT_TO_VALIDATE"
-  - 'if [ "$VALIDATE_COMMIT_MSG" == "true" ]; then ./scripts/validate-commit-msg.sh $COMMIT_TO_VALIDATE; fi'
-  - 'if [ "$LINT" == "true" ]; then npm run lint; fi'
-
-script:
-  - npm run travis
-
-after_success:
-  # run automated release process with semantic-release
-  - echo "TRAVIS_BRANCH=$TRAVIS_BRANCH, TRAVIS_EVENT_TYPE=$TRAVIS_EVENT_TYPE, TRAVIS_NODE_VERSION=$TRAVIS_NODE_VERSION"
-  - if [[ "$TRAVIS_BRANCH" == "master" && "$TRAVIS_EVENT_TYPE" == "push" && "$TRAVIS_NODE_VERSION" == "12" ]]; then
-      npm run semantic-release;
-    fi;

package.json

@@ -500,7 +500,6 @@
     "init": "rm -rf node_modules/karma && cd node_modules && ln -nsf ../ karma && cd ../",
     "init:windows": "(IF EXIST node_modules\\karma (rmdir node_modules\\karma /S /q)) && npm run link",
     "appveyor": "npm run build && npm run test:appveyor",
-    "travis": "npm run build && npm test && npm run test:integration",
     "semantic-release": "semantic-release"
   }
 }