Add plugin tests for happy-dom environment

Author: Mariovido

packages/datadog-plugin-jest/test/circus.spec.js

@@ -44,20 +44,25 @@ function loadAgent (moduleName, version, isAgentlessTest, isEvpProxyTest) {
   if (!isEvpProxyTest) {
     agent.setAvailableEndpoints([])
   }
+  const isHappyDom = moduleName === '@happy-dom/jest-environment'
   return agent.load(['jest', 'http'], { service: 'test' }, { experimental: { exporter } }).then(() => {
     global.__libraryName__ = moduleName
     global.__libraryVersion__ = version
 
     return {
-      jestExecutable: require(`../../../versions/jest@${version}`).get(),
+      jestExecutable: isHappyDom
+        ? require('../../../versions/jest').get()
+        : require(`../../../versions/jest@${version}`).get(),
       jestCommonOptions: {
         projects: [__dirname],
         testPathIgnorePatterns: ['/node_modules/'],
         coverageReporters: ['none'],
         reporters: [],
         silent: true,
-        testEnvironment: path.join(__dirname, 'env.js'),
-        testRunner: require(`../../../versions/jest-circus@${version}`).getPath('jest-circus/runner'),
+        testEnvironment: isHappyDom ? '@happy-dom/jest-environment' : path.join(__dirname, 'env.js'),
+        testRunner: isHappyDom
+          ? require('../../../versions/jest-circus').getPath('jest-circus/runner')
+          : require(`../../../versions/jest-circus@${version}`).getPath('jest-circus/runner'),
         cache: false,
         maxWorkers: '50%'
       }
@@ -72,7 +77,9 @@ describe('Plugin', function () {
   this.timeout(testTimeout)
   this.retries(2)
 
-  withVersions('jest', ['jest-environment-node', 'jest-environment-jsdom'], (version, moduleName) => {
+  const versions = ['jest-environment-node', 'jest-environment-jsdom', '@happy-dom/jest-environment']
+
+  withVersions('jest', versions, (version, moduleName) => {
     afterEach(() => {
       delete process.env.DD_API_KEY
       const jestTestFile = fs.readdirSync(__dirname).filter(name => name.startsWith('jest-'))