feat: Adding a MockAuthService, improving docs (#92)

The mock auth service uses axios-mock-adapter in its implementation to allow mocking of any http client calls the auth service might make on behalf of an application.

This PR also fleshes out the docs for the auth service to try to add some detail around the differences between the interface, AxiosJwtAuthService, and new MockAuthService implementations.

package.json

@@ -35,7 +35,6 @@
     "@commitlint/config-angular": "8.2.0",
     "@edx/frontend-build": "2.0.6",
     "@edx/paragon": "7.1.5",
-    "axios-mock-adapter": "1.17.0",
     "babel-polyfill": "6.26.0",
     "codecov": "3.6.5",
     "enzyme": "3.10.0",
@@ -53,6 +52,7 @@
   "dependencies": {
     "@cospired/i18n-iso-languages": "2.1.2",
     "axios": "0.18.1",
+    "axios-mock-adapter": "1.17.0",
     "form-urlencoded": "4.1.4",
     "glob": "7.1.6",
     "history": "4.10.1",

src/auth/AxiosJwtAuthService.js

@@ -62,18 +62,19 @@ class AxiosJwtAuthService {
   }
 
   /**
-   * Gets the authenticated HTTP client singleton which is an axios instance.
+   * Gets the authenticated HTTP client for the service.  This is an axios instance.
    *
-   * @returns {HttpClient} Singleton. A configured axios http client
+   * @returns {HttpClient} A configured axios http client which can be used for authenticated
+   * requests.
    */
   getAuthenticatedHttpClient() {
     return this.authenticatedHttpClient;
   }
 
   /**
-   * Gets the unauthenticated HTTP lient singleton which is an axios instance.
+   * Gets the unauthenticated HTTP client for the service.  This is an axios instance.
    *
-   * @returns {HttpClient} Singleton. A configured axios http client
+   * @returns {HttpClient} A configured axios http client.
    */
   getHttpClient() {
     return this.httpClient;
@@ -157,7 +158,6 @@ class AxiosJwtAuthService {
    * Sets the authenticated user to the provided value.
    *
    * @param {UserData} authUser
-   * @emits AUTHENTICATED_USER_CHANGED
    */
   setAuthenticatedUser(authUser) {
     this.authenticatedUser = authUser;