Add IE11 testing via BrowserStack to the test matrix.

This aligns the plugin with the support level in core. Note that this
commit also ensures the Chrome headless tests run on CI.

.github/workflows/ci.yml

@@ -3,6 +3,10 @@ name: Tests
   push:
   pull_request:
 
+env:
+  BROWSER_STACK_ACCESS_KEY: '${{ secrets.BROWSER_STACK_ACCESS_KEY }}'
+  BROWSER_STACK_USERNAME: '${{ secrets.BROWSER_STACK_USERNAME }}'
+
 jobs:
   test:
     runs-on: ubuntu-18.04
@@ -32,6 +36,10 @@ jobs:
             target: 'lint'
           - name: 'Coverage'
             target: 'coverage'
+          - name: 'Browser - IE11'
+            target: 'test-browser-ie11'
+          - name: 'Chrome Headless'
+            target: 'test-headless'
 
     steps:
       - uses: actions/checkout@v2

karma.conf.js

@@ -15,6 +15,18 @@ module.exports = function (config) {
       },
     },
 
-    browsers: ['ChromeHeadless'],
+    browsers: ['ChromeHeadless', 'ie11'],
+
+    customLaunchers: {
+      ie11: {
+        base: 'BrowserStack',
+        browser: 'IE',
+        browser_version: '11',
+        os: 'Windows',
+        os_version: '7',
+      },
+    },
+
+    reporters: ['dots', 'BrowserStack'],
   });
 };

package.json

@@ -10,10 +10,12 @@
     "unexpected-snapshot-browser.js.map"
   ],
   "scripts": {
+    "build": "./build.sh",
     "lint": "eslint . && prettier --check '**/*.{js,md}'",
     "test": "mocha",
-    "build": "./build.sh",
-    "test-headless": "npm run build && karma start --single-run",
+    "test-browser": "npm run build && karma start --single-run --browsers ${BROWSER:-ChromeHeadless}",
+    "test-browser-ie11": "BROWSER=ie11 npm run test-browser",
+    "test-headless": "npm run test-browser",
     "coverage": "nyc --reporter=lcov --reporter=text --all -- mocha && echo google-chrome coverage/lcov-report/index.html",
     "prepublishOnly": "npm run build",
     "preversion": "offline-github-changelog --next=${npm_package_version} > CHANGELOG.md && git add CHANGELOG.md"
@@ -43,6 +45,7 @@
     "eslint-plugin-standard": "^5.0.0",
     "espree": "^7.0.0",
     "karma": "^5.0.1",
+    "karma-browserstack-launcher": "^1.6.0",
     "karma-chrome-launcher": "^3.0.0",
     "karma-mocha": "^2.0.0",
     "mocha": "^8.0.1",

test/browser/index.js

@@ -1,6 +1,7 @@
 /* global weknowhow, unexpectedSnapshot */
 
-const expect = weknowhow.expect.clone().use(unexpectedSnapshot);
+// eslint-disable-next-line no-var
+var expect = weknowhow.expect.clone().use(unexpectedSnapshot);
 
 describe('unexpected-snapshot', function () {
   describe('to equal snapshot', function () {
@@ -10,7 +11,9 @@ describe('unexpected-snapshot', function () {
 
     it('should fail with a diff', function () {
       expect(
-        () => expect('abc', 'to equal snapshot', 'def'),
+        function () {
+          expect('abc', 'to equal snapshot', 'def');
+        },
         'to throw',
         "expected 'abc' to equal snapshot 'def'\n" +
           '\n' +
@@ -37,12 +40,13 @@ describe('unexpected-snapshot', function () {
 
     it('should fail with a diff', function () {
       expect(
-        () =>
+        function () {
           expect(
             new Person('Eigil'),
             'to equal snapshot',
             "Person({ name: 'Preben' })"
-          ),
+          );
+        },
         'to throw',
         "expected Person({ name: 'Eigil' }) to equal snapshot 'Person({ name: \\'Preben\\' })'\n" +
           '\n' +