build: setup cronjob to run tests against angular snapshots

* Sets up a cronjob workflow that runs the local browser tests against the Angular Github snapshot builds at midnight everyday.
* No longer saves cache multiple times. This can cause unexpected behavior.
* Sorts jobs in `config.yml` to group all `tests_XX` jobs.

Closes #12516.

Author: devversion

.circleci/config.yml

@@ -91,24 +91,6 @@ jobs:
       - run: bazel build src/...
       - run: bazel test src/... tools/public_api_guard/...
 
-  # ------------------------------------------------------------------------------------------
-  # Job that runs the unit tests on locally installed browsers (Chrome and Firefox headless).
-  # The available browsers are installed through the angular/ngcontainer Docker image.
-  # ------------------------------------------------------------------------------------------
-  tests_local_browsers:
-    docker: *docker-firefox-image
-    resource_class: xlarge
-    environment:
-      TEST_PLATFORM: local
-    steps:
-      - *checkout_code
-      - *restore_cache
-      - *yarn_install
-
-      # Launches the unit tests. The platform is determined by the "TEST_PLATFORM" environment
-      # variable which has been configured above
-      - run: yarn gulp ci:test
-
   # ----------------------------------------------------------------
   # Job that runs the e2e tests with Protractor and Chrome Headless
   # ----------------------------------------------------------------
@@ -122,6 +104,20 @@ jobs:
 
       - run: yarn gulp ci:e2e
 
+  # ------------------------------------------------------------------------------------------
+  # Job that runs the unit tests on locally installed browsers (Chrome and Firefox headless).
+  # The available browsers are installed through the angular/ngcontainer Docker image.
+  # ------------------------------------------------------------------------------------------
+  tests_local_browsers:
+    docker: *docker-firefox-image
+    resource_class: xlarge
+    steps:
+    - *checkout_code
+    - *restore_cache
+    - *yarn_install
+
+    - run: ./scripts/run-local-browser-tests.sh
+
   # ----------------------------------------------------------------------------
   # Job that runs the unit tests on Browserstack. The browsers that will be used
   # to run the unit tests on Browserstack are set in: test/browser-providers.js
@@ -269,8 +265,6 @@ jobs:
 
       - run: ./scripts/circleci/publish-snapshots.sh
 
-      - *save_cache
-
 # ----------------------------------------------------------------------------------------
 # Workflow definitions. A workflow usually groups multiple jobs together. This is useful if
 # one job depends on another.
@@ -313,6 +307,22 @@ workflows:
     jobs:
       - lint
 
+  # Snapshot tests workflow that is scheduled to run all specified jobs at midnight everyday.
+  # This workflow runs various jobs against the Angular snapshot builds from Github.
+  snapshot_tests:
+    jobs:
+      - tests_local_browsers
+    triggers:
+      - schedule:
+          cron: "0 0 * * *"
+          filters:
+            branches:
+              only:
+                # We only want to run the "master" branch against the snapshot builds because
+                # it's not guaranteed that older versions of Angular Material always work
+                # with the latest Angular version.
+                - master
+
 # ---------------------------
 # General setup for CircleCI
 # ---------------------------

scripts/circleci/run-local-browser-tests.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+# In case any command failed, we want to immediately exit the script with the
+# proper exit code.
+set -e
+
+# Go to project directory.
+cd $(dirname ${0})/../..
+
+# In case the "snapshot_tests" workflow is currently running this script, we
+# want to run the local browser tests against the Angular snapshot builds.
+if [[ "${CIRCLE_WORKFLOW_ID}" == "snapshot_tests" ]]; then
+  ./scripts/install-angular-snapshots.sh
+fi
+
+# Setup the test platform environment variable that will be read
+# by the Karma configuration script.
+export TEST_PLATFORM="local"
+
+# Run the unit tests on the local browsers with Karma.
+yarn gulp ci:test