Add build mode tests

Author: NullVoxPopuli

tests/fixtures/build-mode-tests/debug-utils-test.js

@@ -0,0 +1,10 @@
+import { test, module } from 'qunit';
+import { assert } from '@ember/debug';
+
+module('debug utils remain in the build', function () {
+  test('debug utils work in tests', function(qAssert) {
+    qAssert.throws(() => {
+      assert('it works', false);
+    }, 'it works');
+  });
+});

tests/smoke-tests/defaults.test.ts

@@ -115,6 +115,11 @@ for (let packageManager of SUPPORTED_PACKAGE_MANAGERS) {
 
         let testFixture = fixturify.readSync('./fixtures/rendering-tests');
         fixturify.writeSync(join(addonDir, 'tests/rendering'), testFixture);
+
+        fixturify.writeSync(
+          join(addonDir, 'tests/unit'),
+          fixturify.readSync('./fixtures/build-mode-tests'),
+        );
       });
 
       it('lint:fix', async () => {