Add test framework (chartjs#287)

* Add test framework

.eslintrc.yml

@@ -1,7 +1,7 @@
 
 extends:
   - chartjs
-  - plugin:es/no-2019
+  - plugin:es/no-new-in-es2019
 
 env:
   es6: true

.github/workflows/ci.yml

@@ -9,18 +9,26 @@ on:
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+
+    outputs:
+      coveralls: ${{ steps.changes.outputs.src }}
 
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x]
+        os: [ubuntu-latest, windows-latest]
+      fail-fast: false
 
     steps:
     - uses: actions/checkout@v2
-    - name: Use Node.js ${{ matrix.node-version }}
+    - name: Use Node.js
       uses: actions/setup-node@v1
-      with:
-        node-version: ${{ matrix.node-version }}
-    - run: npm ci
-    - run: npm run build --if-present
-    - run: npm test
+    - run: |
+        npm ci
+        npm run build
+        if [ "${{ runner.os }}" == "Windows" ]; then
+          npm test
+        else
+          xvfb-run --auto-servernum npm test
+        fi
+      shell: bash

karma.conf.js

@@ -0,0 +1,106 @@
+const istanbul = require('rollup-plugin-istanbul');
+const resolve = require('@rollup/plugin-node-resolve').default;
+const builds = require('./rollup.config');
+const yargs = require('yargs');
+
+module.exports = function(karma) {
+	const args = yargs
+		.option('verbose', {default: false})
+		.argv;
+
+	const grep = args.grep === true ? '' : args.grep;
+	const specPattern = 'test/specs/**/*' + grep + '*.js';
+
+	// Use the same rollup config as our dist files: when debugging (npm run dev),
+	// we will prefer the unminified build which is easier to browse and works
+	// better with source mapping. In other cases, pick the minified build to
+	// make sure that the minification process (terser) doesn't break anything.
+	const regex = karma.autoWatch ? /chartjs-plugin-annotation\.js$/ : /chartjs-plugin-annotation\.min\.js$/;
+	const build = builds.filter(v => v.output.file && v.output.file.match(regex))[0];
+
+	if (args.coverage) {
+		build.plugins = [
+			resolve(),
+			istanbul({exclude: ['node_modules/**/*.js', 'package.json']})
+		];
+	}
+
+	karma.set({
+		frameworks: ['jasmine'],
+		reporters: ['progress', 'kjhtml'],
+		browsers: (args.browsers || 'chrome,firefox').split(','),
+		logLevel: karma.LOG_INFO,
+
+		client: {
+			jasmine: {
+				failFast: !!karma.autoWatch
+			}
+		},
+
+		// Explicitly disable hardware acceleration to make image
+		// diff more stable when ran on Travis and dev machine.
+		// https://github.com/chartjs/Chart.js/pull/5629
+		customLaunchers: {
+			chrome: {
+				base: 'Chrome',
+				flags: [
+					'--disable-accelerated-2d-canvas'
+				]
+			},
+			firefox: {
+				base: 'Firefox',
+				prefs: {
+					'layers.acceleration.disabled': true
+				}
+			}
+		},
+
+		files: [
+			{pattern: 'test/fixtures/**/*.js', included: false},
+			{pattern: 'test/fixtures/**/*.png', included: false},
+			{pattern: 'node_modules/chart.js/dist/chart.js'},
+			{pattern: 'src/index.js', watched: false},
+			{pattern: 'test/index.js'},
+			{pattern: specPattern}
+		],
+
+		preprocessors: {
+			'src/index.js': ['sources'],
+			'test/index.js': ['rollup']
+		},
+
+		rollupPreprocessor: {
+			plugins: [
+				resolve(),
+			],
+			output: {
+				name: 'test',
+				format: 'umd',
+				sourcemap: karma.autoWatch ? 'inline' : false
+			}
+		},
+
+		customPreprocessors: {
+			sources: {
+				base: 'rollup',
+				options: build
+			}
+		},
+
+		// These settings deal with browser disconnects. We had seen test flakiness from Firefox
+		// [Firefox 56.0.0 (Linux 0.0.0)]: Disconnected (1 times), because no message in 10000 ms.
+		// https://github.com/jasmine/jasmine/issues/1327#issuecomment-332939551
+		browserDisconnectTolerance: 3
+	});
+
+	if (args.coverage) {
+		karma.reporters.push('coverage');
+		karma.coverageReporter = {
+			dir: 'coverage/',
+			reporters: [
+				{type: 'html', subdir: 'html'},
+				{type: 'lcovonly', subdir: (browser) => browser.toLowerCase().split(/[ /-]/)[0]}
+			]
+		};
+	}
+};