diff --git a/.github/workflows/it-tests.yml b/.github/workflows/it-tests.yml
index f8a6beb075..35b1eb92c4 100644
--- a/.github/workflows/it-tests.yml
+++ b/.github/workflows/it-tests.yml
@@ -51,7 +51,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest]
-        packageManager: [yarn, npm]
+        packageManager: [yarn, npm, yarn1]
         testEnvironment: [o3r-project-with-app]
     runs-on: ${{ matrix.os }}
     env:
diff --git a/packages/@o3r/test-helpers/src/prepare-test-env.ts b/packages/@o3r/test-helpers/src/prepare-test-env.ts
index 854c09d39f..e85c96e840 100644
--- a/packages/@o3r/test-helpers/src/prepare-test-env.ts
+++ b/packages/@o3r/test-helpers/src/prepare-test-env.ts
@@ -3,7 +3,7 @@ import { cpSync, existsSync, mkdirSync, readdirSync, readFileSync, rmSync, statS
 import * as path from 'node:path';
 import type { PackageJson } from 'type-fest';
 import { createTestEnvironmentBlank } from './test-environments/create-test-environment-blank';
-import { createWithLock, getPackageManager, type Logger, packageManagerInstall, setPackagerManagerConfig, setupGit } from './utilities/index';
+import { createWithLock, getPackageManager, isYarn1, type Logger, packageManagerInstall, setPackagerManagerConfig, setupGit, YARN_1_LATEST_VERSION } from './utilities/index';
 import { createTestEnvironmentOtterProjectWithApp } from './test-environments/create-test-environment-otter-project';
 import { O3rCliError } from '@o3r/schematics';
 
@@ -15,8 +15,7 @@ export type PrepareTestEnvType = 'blank' | 'o3r-project-with-app';
 
 /**
  * Retrieve the version used by yarn and setup at root level
- * @param rootFolderPath: path to the folder where to take the configuration from
- * @param rootFolderPath
+ * @param rootFolderPath path to the folder where to take the configuration from
  */
 export function getYarnVersionFromRoot(rootFolderPath: string) {
   const o3rPackageJson: PackageJson & { generatorDependencies?: Record<string, string> } =
@@ -49,7 +48,7 @@ export async function prepareTestEnv(folderName: string, options?: PrepareTestEn
   const cacheFolderPath = path.resolve(globalFolderPath, 'cache');
 
   JSON.parse(readFileSync(path.join(rootFolderPath, 'packages', '@o3r', 'core', 'package.json')).toString());
-  const yarnVersion: string = yarnVersionParam || getYarnVersionFromRoot(rootFolderPath);
+  const yarnVersion: string = yarnVersionParam || (isYarn1() && YARN_1_LATEST_VERSION) || getYarnVersionFromRoot(rootFolderPath);
   const execAppOptions: ExecSyncOptions = {
     cwd: workspacePath,
     stdio: 'inherit',
diff --git a/packages/@o3r/test-helpers/src/utilities/package-manager.ts b/packages/@o3r/test-helpers/src/utilities/package-manager.ts
index 02a1d82c90..c2178803d4 100644
--- a/packages/@o3r/test-helpers/src/utilities/package-manager.ts
+++ b/packages/@o3r/test-helpers/src/utilities/package-manager.ts
@@ -49,6 +49,19 @@ export function getPackageManager() {
     'yarn';
 }
 
+
+/**
+ * latest version of yarn 1
+ */
+export const YARN_1_LATEST_VERSION = '1.22.19';
+
+/**
+ * is yarn 1
+ */
+export function isYarn1() {
+  return process.env.ENFORCED_PACKAGE_MANAGER === 'yarn1';
+}
+
 /**
  * Need to add additional dashes when running command like exec on npm
  * Convert `npm exec test --param` to `npm exec test -- --param`