Add support to run tests with vitest

Author: acelaya

lib/tests.js

@@ -14,7 +14,8 @@ import { buildJS, watchJS } from './rollup.js';
  *   @param {string} options.bootstrapFile - Entry point for the test bundle that initializes the environment
  *   @param {string} options.rollupConfig - Rollup config that generates the test bundle using
  *     `${outputDir}/test-inputs.js` as an entry point
- *   @param {string} options.karmaConfig - Karma config file
+ *   @param {string} [options.karmaConfig] - Karma config file. Will use karma to run tests
+ *   @param {string} [options.vitestConfig] - Vitest config file. Will use vitest to run tests
  *   @param {string} options.outputDir - Directory in which to generate test bundle. Defaults to
  *     `build/scripts`
  *   @param {string} options.testsPattern - Minimatch pattern that specifies which test files to
@@ -26,6 +27,7 @@ export async function runTests({
   rollupConfig,
   outputDir = 'build/scripts',
   karmaConfig,
+  vitestConfig,
   testsPattern,
 }) {
   // Parse command-line options for test execution.
@@ -64,30 +66,45 @@ export async function runTests({
     await watchJS(rollupConfig);
   }
 
-  // Run the tests.
-  log('Starting Karma...');
-  const { default: karma } = await import('karma');
-  const parsedConfig = await karma.config.parseConfig(
-    path.resolve(karmaConfig),
-    { singleRun },
-  );
+  // Run the tests with vitest. Karma takes precedence if both are defined
+  if (vitestConfig && !karmaConfig) {
+    log('Starting vitest...');
+    const [{ startVitest }, vitestOptions] = await Promise.all([
+      import('vitest/node'),
+      import(path.resolve(vitestConfig)),
+    ]);
+    await startVitest('test', [], {
+      watch: live,
+      ...vitestOptions,
+    });
+  }
 
-  return new Promise((resolve, reject) => {
-    new karma.Server(parsedConfig, exitCode => {
-      if (exitCode === 0) {
-        resolve();
-      } else {
-        reject(new Error(`Karma run failed with status ${exitCode}`));
-      }
-    }).start();
+  // Run the tests with karma.
+  if (karmaConfig) {
+    log('Starting Karma...');
+    const { default: karma } = await import('karma');
+    const parsedConfig = await karma.config.parseConfig(
+      path.resolve(karmaConfig),
+      { singleRun },
+    );
 
-    process.on('SIGINT', () => {
-      // Give Karma a chance to handle SIGINT and cleanup, but forcibly
-      // exit if it takes too long.
-      setTimeout(() => {
-        resolve();
-        process.exit(1);
-      }, 5000);
+    return new Promise((resolve, reject) => {
+      new karma.Server(parsedConfig, exitCode => {
+        if (exitCode === 0) {
+          resolve();
+        } else {
+          reject(new Error(`Karma run failed with status ${exitCode}`));
+        }
+      }).start();
+
+      process.on('SIGINT', () => {
+        // Give Karma a chance to handle SIGINT and cleanup, but forcibly
+        // exit if it takes too long.
+        setTimeout(() => {
+          resolve();
+          process.exit(1);
+        }, 5000);
+      });
     });
-  });
+  }
 }

package.json

@@ -26,7 +26,8 @@
     "rollup": "^4.0.2",
     "sass": "^1.43.2",
     "tailwindcss": "^3.0.11",
-    "typescript": "^5.0.2"
+    "typescript": "^5.0.2",
+    "vitest": "^3.1.1"
   },
   "dependencies": {
     "commander": "^13.0.0",
@@ -39,11 +40,18 @@
     "postcss": "^8.3.9",
     "rollup": "^4.0.2",
     "sass": "^1.43.2",
-    "tailwindcss": "^3.0.11"
+    "tailwindcss": "^3.0.11",
+    "vitest": "^3.1.1"
   },
   "peerDependenciesMeta": {
+    "karma": {
+      "optional": true
+    },
     "tailwindcss": {
       "optional": true
+    },
+    "vitest": {
+      "optional": true
     }
   },
   "prettier": {