Creates test request helper for API endpoints

Separates common utils into the medusa-core-utils package.
Sets up a testing environment where mocked models/services/etc. can be placed in
__mocks__ folder within its corresponding directory. The mocks will
automatically be registered in a awilix container only used for testing.

packages/medusa/src/services/auth.js

@@ -13,6 +13,33 @@ class AuthService extends BaseService {
     this.userModel_ = userModel
   }
 
+  /**
+   * Authenticates a given user with an API token
+   * @param {string} token - the api_token of the user to authenticate
+   * @return {{
+   *    success: (bool),
+   *    user: (object | undefined),
+   *    error: (string | undefined)
+   * }}
+   *    success: whether authentication succeeded
+   *    user: the user document if authentication succeded
+   *    error: a string with the error message
+   */
+  async authenticateAPIToken(token) {
+    const user = await this.userModel_.findOne({ api_token: token })
+
+    if (user) {
+      return {
+        success: true,
+        user,
+      }
+    } else {
+      return {
+        success: false,
+        error: "Invalid API Token",
+      }
+    }
+  }
   /**
    * Authenticates a given user based on an email, password combination. Uses
    * bcrypt to match password with hashed value.