diff --git a/packages/-ember-data/package.json b/packages/-ember-data/package.json
index 282b51ad419..3bc3ac6b0dd 100644
--- a/packages/-ember-data/package.json
+++ b/packages/-ember-data/package.json
@@ -10,7 +10,7 @@
   "scripts": {
     "build": "ember build",
     "build:production": "ember build --environment=production",
-    "start": "ember server",
+    "start": "ember serve",
     "docs": "mkdir -p dist && ember ember-cli-yuidoc",
     "test": "ember test",
     "test:all": "ember try:each",
diff --git a/packages/-ember-data/tests/integration/store/model-name-test.js b/packages/-ember-data/tests/integration/store/model-name-test.js
index 56a0b434fd4..f4ca9f94b8d 100644
--- a/packages/-ember-data/tests/integration/store/model-name-test.js
+++ b/packages/-ember-data/tests/integration/store/model-name-test.js
@@ -64,7 +64,9 @@ module('@ember-data/model klass.modelName', function(hooks) {
       assert.strictEqual(
         startsWith(e.message, `Cannot assign to read only property 'modelName' of `) ||
           // IE11 has a different message
-          startsWith(e.message, `Assignment to read-only properties is not allowed in strict mode`),
+          startsWith(e.message, `Assignment to read-only properties is not allowed in strict mode`) ||
+          // Safari aso has a different message
+          startsWith(e.message, `Attempted to assign to readonly property`),
         true,
         `modelName is immutable: ${e.message}`
       );
diff --git a/packages/unpublished-test-infra/addon-test-support/deprecated-test.js b/packages/unpublished-test-infra/addon-test-support/deprecated-test.js
index d635e354e74..4e7ae7f02f9 100644
--- a/packages/unpublished-test-infra/addon-test-support/deprecated-test.js
+++ b/packages/unpublished-test-infra/addon-test-support/deprecated-test.js
@@ -2,7 +2,7 @@ import { DEBUG } from '@glimmer/env';
 
 import { skip, test } from 'qunit';
 
-import VERSION, { COMPAT_VERSION } from '@ember-data/unpublished-test-infra/version';
+import VERSION, { COMPAT_VERSION } from '@ember-data/unpublished-test-infra/test-support/version';
 
 // small comparison function for major and minor semver values
 function gte(EDVersion, DeprecationVersion) {
diff --git a/packages/unpublished-test-infra/index.js b/packages/unpublished-test-infra/index.js
index 08df794a141..ba4f2d9280a 100644
--- a/packages/unpublished-test-infra/index.js
+++ b/packages/unpublished-test-infra/index.js
@@ -1,5 +1,6 @@
 'use strict';
-
+// eslint-disable-next-line node/no-unpublished-require
+const merge = require('broccoli-merge-trees');
 const version = require('@ember-data/private-build-infra/src/create-version-module');
 const addonBuildConfigForDataPackage = require('@ember-data/private-build-infra/src/addon-build-config-for-data-package');
 
@@ -8,12 +9,11 @@ const name = require('./package').name;
 const addonBaseConfig = addonBuildConfigForDataPackage(name);
 
 module.exports = Object.assign({}, addonBaseConfig, {
-  treeForAddon() {
-    if (process.env.EMBER_CLI_TEST_COMMAND) {
-      const options = this.getEmberDataConfig();
-      let compatVersion = options.compatWith;
-      let tree = version(compatVersion);
-      return this.debugTree(this._super.treeForAddon.call(this, tree), 'addon-output');
-    }
+  treeForAddonTestSupport(existingTree) {
+    const options = this.getEmberDataConfig();
+    let compatVersion = options.compatWith;
+    let tree = merge([existingTree, version(compatVersion)]);
+
+    return this.debugTree(this._super.treeForAddonTestSupport.call(this, tree), 'test-support');
   },
 });
diff --git a/packages/unpublished-test-infra/package.json b/packages/unpublished-test-infra/package.json
index 59185452771..06cc88e8653 100644
--- a/packages/unpublished-test-infra/package.json
+++ b/packages/unpublished-test-infra/package.json
@@ -26,6 +26,7 @@
     "testem": "^3.0.3"
   },
   "devDependencies": {
+    "broccoli-merge-trees": "^4.2.0",
     "@ember/optional-features": "^1.3.0",
     "ember-cli": "~3.18.0",
     "ember-cli-dependency-checker": "^3.2.0",