Add karma to run unit tests

karma.conf.js

@@ -0,0 +1,127 @@
+/**
+ * @license
+ * Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
+ * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+ * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+ * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+ * Code distributed by Google as part of the polymer project is also
+ * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+ */
+
+// Karma configuration
+// Generated on Fri Apr 27 2018 14:35:10 GMT+0100 (BST)
+
+const fs = require("fs");
+
+
+function readJsonFile(path) {
+  // TypeScript puts lots of comments in the default `tsconfig.json`, so you
+  // can’t use `require()` to read it. Hence this hack.
+  return eval("(" + fs.readFileSync(path).toString("utf-8") + ")");
+}
+
+const typeScriptConfig = readJsonFile("./tsconfig.json");
+const babel = readJsonFile("./.babelrc");
+
+module.exports = function(config) {
+  const options = {
+    // base path that will be used to resolve all patterns (eg. files, exclude)
+    basePath: "",
+
+    // frameworks to use
+    // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
+    frameworks: ["mocha", "chai", "karma-typescript"],
+
+    // list of files / patterns to load in the browser
+    files: [
+      {
+        pattern: "test/**/*.ts",
+        type: "module"
+      },
+      {
+        pattern: "src/**/*.ts",
+        included: false
+      }
+    ],
+
+    // list of files / patterns to exclude
+    exclude: [],
+// preprocess matching files before serving them to the browser // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
+    preprocessors: {
+      "src/**/*.ts": ["karma-typescript", "babel"],
+      "test/**/*.ts": ["karma-typescript", "babel"]
+    },
+    babelPreprocessor: {
+      options: babel
+    },
+    karmaTypescriptConfig: {
+      // Inline `tsconfig.json` so that the right TS libs are loaded
+      ...typeScriptConfig,
+      // Coverage is a thing that karma-typescript forces on you and only
+      // creates problems. This is the simplest way of disabling it that I
+      // could find.
+      coverageOptions: {
+        exclude: /.*/
+      }
+    },
+    mime: {
+      // Default mimetype for .ts files is video/mp2t but we need
+      // text/javascript for modules to work.
+      "text/javascript": ["ts"]
+    },
+    plugins: [
+      // Load all modules whose name starts with "karma" (usually the default).
+      "karma-*",
+      // We don’t have file extensions on our imports as they are primarily
+      // consumed by webpack.  With Karma, however, this turns into a real HTTP
+      // request for a non-existent file. This inline plugin is a middleware
+      // that appends `.ts` to the request URL.
+      {
+        "middleware:redirect_to_ts": [
+          "value",
+          (req, res, next) => {
+            if (req.url.startsWith("/base/src")) {
+              req.url += '.ts';
+            }
+            next();
+          }
+        ]
+      }
+    ],
+    // Run our middleware before all other middlewares.
+    beforeMiddleware: ["redirect_to_ts"],
+
+    // test results reporter to use
+    // possible values: 'dots', 'progress'
+    // available reporters: https://npmjs.org/browse/keyword/karma-reporter
+    reporters: ["progress"],
+
+    // web server port
+    port: 9876,
+
+    // enable / disable colors in the output (reporters and logs)
+    colors: true,
+
+    // level of logging
+    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
+    logLevel: config.LOG_INFO,
+
+    // enable / disable watching file and executing tests whenever any file changes
+    autoWatch: false,
+
+    // start these browsers
+    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
+    browsers: ["ChromeHeadless"],
+
+    // Continuous Integration mode
+    // if true, Karma captures browsers, runs the tests and exits
+    singleRun: true,
+
+    // These custom files allow us to use ES6 modules in our tests.
+    // Remove these 2 lines (and files) once https://github.com/karma-runner/karma/pull/2834 lands.
+    customContextFile: "test/context.html",
+    customDebugFile: "test/debug.html"
+  };
+
+  config.set(options);
+};