support new embroider working dir introduced in embroider/compat >3.1

packages/ember-cli-code-coverage/index.js

@@ -55,11 +55,20 @@ module.exports = {
     }
 
     if (opts.embroider === true) {
-      let {
-        stableWorkspaceDir,
+      try {
+        // Attempt to import the utility @embroider/compat uses in >3.1 to locate the embroider working directory
+        // the presence of this `locateEmbroiderWorkingDir` method coincides with the shift to utilize `rewritten-app` tmp dir
         // eslint-disable-next-line node/no-missing-require
-      } = require('@embroider/compat/src/default-pipeline');
-      cwd = stableWorkspaceDir(cwd, process.env.EMBER_ENV);
+        let { locateEmbroiderWorkingDir } = require('@embroider/core');
+        cwd = path.resolve(locateEmbroiderWorkingDir(cwd), 'rewritten-app');
+      } catch (err) {
+        // otherwise, fall back to the method used in embroider <3.1
+        let {
+          stableWorkspaceDir,
+          // eslint-disable-next-line node/no-missing-require
+        } = require('@embroider/compat/src/default-pipeline');
+        cwd = stableWorkspaceDir(cwd, process.env.EMBER_ENV);
+      }
     }
 
     const IstanbulPlugin = require.resolve('babel-plugin-istanbul');
@@ -116,12 +125,8 @@ module.exports = {
    * If coverage is enabled attach coverage middleware to the express server run by ember-cli
    * @param {Object} startOptions - Express server start options
    */
-  serverMiddleware(startOptions) {
-    attachMiddleware.serverMiddleware(startOptions.app, {
-      configPath: this.project.configPath(),
-      root: this.project.root,
-      namespaceMappings: this.buildNamespaceMappings(),
-    });
+  serverMiddleware(startOptions, config) {
+    attachMiddleware.serverMiddleware(startOptions.app, config);
   },
 
   testemMiddleware(app) {

packages/ember-cli-code-coverage/lib/attach-middleware.js

@@ -22,8 +22,15 @@ function logError(err, req, res, next) {
  * in-repo-namespace/components/foo.js.
  */
 function normalizeRelativePath(root, filepath) {
-  let embroiderTmpPathRegex = /embroider\/.{6}/gm;
-  let relativePath = filepath.split(embroiderTmpPathRegex)[1].slice(1);
+  let relativePath;
+  let embroiderCompatLT31TmpPathRegex = /embroider\/.{6}/gm;
+  let embroiderCompatGT31TmpPathRegex = /\.embroider\/rewritten-app\//gm;
+
+  if (embroiderCompatGT31TmpPathRegex.test(filepath)) {
+    relativePath = filepath.split(embroiderCompatGT31TmpPathRegex)[1];
+  } else {
+    relativePath = filepath.split(embroiderCompatLT31TmpPathRegex)[1].slice(1);
+  }
 
   if (fs.existsSync(path.join(root, 'package.json'))) {
     let pkgJSON = fs.readJsonSync(path.join(root, 'package.json'));

test-packages/__snapshots__/my-embroider-app-test.mjs.snap

@@ -266,3 +266,92 @@ exports[`app coverage generation > generates coverage with @embroider ^2.1.0 1`]
   },
 }
 `;
+
+exports[`app coverage generation > generates coverage with @embroider ^3.1.0 1`] = `
+{
+  "app/app.js": {
+    "branches": {
+      "covered": 0,
+      "pct": 100,
+      "skipped": 0,
+      "total": 0,
+    },
+    "functions": {
+      "covered": 0,
+      "pct": 100,
+      "skipped": 0,
+      "total": 0,
+    },
+    "lines": {
+      "covered": 4,
+      "pct": 100,
+      "skipped": 0,
+      "total": 4,
+    },
+    "statements": {
+      "covered": 4,
+      "pct": 100,
+      "skipped": 0,
+      "total": 4,
+    },
+  },
+  "app/router.js": {
+    "branches": {
+      "covered": 0,
+      "pct": 100,
+      "skipped": 0,
+      "total": 0,
+    },
+    "functions": {
+      "covered": 0,
+      "pct": 0,
+      "skipped": 0,
+      "total": 1,
+    },
+    "lines": {
+      "covered": 1,
+      "pct": 33.33,
+      "skipped": 0,
+      "total": 3,
+    },
+    "statements": {
+      "covered": 1,
+      "pct": 33.33,
+      "skipped": 0,
+      "total": 3,
+    },
+  },
+  "total": {
+    "branches": {
+      "covered": 0,
+      "pct": 100,
+      "skipped": 0,
+      "total": 0,
+    },
+    "branchesTrue": {
+      "covered": 0,
+      "pct": "Unknown",
+      "skipped": 0,
+      "total": 0,
+    },
+    "functions": {
+      "covered": 0,
+      "pct": 0,
+      "skipped": 0,
+      "total": 1,
+    },
+    "lines": {
+      "covered": 5,
+      "pct": 71.42,
+      "skipped": 0,
+      "total": 7,
+    },
+    "statements": {
+      "covered": 5,
+      "pct": 71.42,
+      "skipped": 0,
+      "total": 7,
+    },
+  },
+}
+`;

test-packages/my-embroider-app-test.mjs

@@ -13,7 +13,7 @@ describe('app coverage generation', function () {
       '^0.47.0',
       '^1.0.0',
       '^2.1.0', 
-      // '^3.1.0' remove when PR https://github.com/ember-cli-code-coverage/ember-cli-code-coverage/pull/387 is merged
+      '^3.1.0'
     ]) {
     it(`generates coverage with @embroider ${embroiderVersion}`, async function (context) {
       let buildPath = await setupTestDir(APP_DIR, env, {