Tests: Adds end-to-end tests skeleton and basic smoke test scenario (#16901)

* Chore: Adds neccessary packages

* Wip: Initial dummy test in place

* Feature: Downloads Chromium if needed

* Fix: Adds global config object

* Refactor: Adds basic e2eScenario

* Build: Adds end to end tests to config

* Build: Changes end to end job

* Build: Adds browsers to image

* Build: Adds failing test

* Refactor: Adds first e2e-test scenario

* Fix: Ignores test output in gitignore

* Refactor: Adds compare screenshots ability

* Refactor: Removes unnecessary code

* Build: Removes jest-puppeteer

* Fix: Replaces test snapshots

* Refactor: Creates output dir if missing

* Refactor: Changes aria-labels to be more consistent

* Docs: Adds section about end to end tests

* Fix: Fixes snapshots

* Docs: Adds information about ENV variables

package.json

@@ -25,12 +25,16 @@
     "@types/commander": "2.12.2",
     "@types/d3": "4.13.1",
     "@types/enzyme": "3.9.0",
+    "@types/expect-puppeteer": "3.3.1",
     "@types/inquirer": "0.0.43",
     "@types/jest": "24.0.11",
     "@types/jquery": "1.10.35",
     "@types/lodash": "4.14.123",
     "@types/node": "11.13.4",
     "@types/papaparse": "4.5.9",
+    "@types/pixelmatch": "4.0.0",
+    "@types/pngjs": "3.3.2",
+    "@types/puppeteer-core": "1.9.0",
     "@types/react": "16.8.16",
     "@types/react-dom": "16.8.4",
     "@types/react-grid-layout": "0.16.7",
@@ -55,6 +59,7 @@
     "es6-promise": "3.3.1",
     "es6-shim": "0.35.5",
     "execa": "1.0.0",
+    "expect-puppeteer": "4.1.1",
     "expect.js": "0.2.0",
     "expose-loader": "0.7.5",
     "file-loader": "3.0.1",
@@ -85,6 +90,7 @@
     "load-grunt-tasks": "3.5.2",
     "mini-css-extract-plugin": "0.5.0",
     "mocha": "4.1.0",
+    "module-alias": "2.2.0",
     "monaco-editor": "0.15.6",
     "ng-annotate-loader": "0.6.1",
     "ng-annotate-webpack-plugin": "0.3.0",
@@ -94,10 +100,13 @@
     "optimize-css-assets-webpack-plugin": "5.0.1",
     "ora": "3.2.0",
     "phantomjs-prebuilt": "2.1.16",
+    "pixelmatch": "4.0.2",
+    "pngjs": "3.4.0",
     "postcss-browser-reporter": "0.5.0",
     "postcss-loader": "3.0.0",
     "postcss-reporter": "6.0.1",
     "prettier": "1.16.4",
+    "puppeteer-core": "1.15.0",
     "react-hooks-testing-library": "0.3.7",
     "react-hot-loader": "4.8.0",
     "react-test-renderer": "16.8.4",
@@ -140,6 +149,7 @@
     "tslint": "tslint -c tslint.json --project tsconfig.json",
     "typecheck": "tsc --noEmit",
     "jest": "jest --notify --watch",
+    "e2e-tests": "jest --runInBand --config=jest.config.e2e.js",
     "api-tests": "jest --notify --watch --config=tests/api/jest.js",
     "storybook": "cd packages/grafana-ui && yarn storybook",
     "storybook:build": "cd packages/grafana-ui && yarn storybook:build",
@@ -242,5 +252,8 @@
       "**/@types/*",
       "**/@types/*/**"
     ]
+  },
+  "_moduleAliases": {
+    "puppeteer": "node_modules/puppeteer-core"
   }
 }