(docs): Add guide for some useful libraries for testing

docs/README.md

@@ -14,6 +14,7 @@ Vue Test Utils is the official unit testing utility library for Vue.js.
   - [Using with TypeScript](guides/using-with-typescript.md)
   - [Using with Vue Router](guides/using-with-vue-router.md)
   - [Using with Vuex](guides/using-with-vuex.md)
+  - [Useful Libraries for Testing](guides/useful-libraries-for-testing.md)
 - [API](api/)
   - [mount](api/mount.md)
   - [shallowMount](api/shallowMount.md)

docs/guides/useful-libraries-for-testing.md

@@ -0,0 +1,15 @@
+## Useful Libraries for Testing
+
+Vue Test Utils provides useful methods for testing Vue components. Community members have also written some additional libraries which either extend `vue-test-utils` with extra useful methods, or provide tools for testing other things found in Vue applications.
+
+### `vuex-mock-store`
+
+[`vuex-mock-store`](https://github.com/posva/vuex-mock-store) provides a simple and straightforward mock store to simplify testing components consuming a Vuex store.
+
+### `jest-matcher-vue-test-utils`
+
+[`jest-matcher-vue-test-utils`](https://github.com/hmsk/jest-matcher-vue-test-utils) adds additional matchers for the Jest test runner with the goal of making assertions more expressive.
+
+### `jest-mock-axios`
+
+[`jest-mock-axios`](https://github.com/knee-cola/jest-mock-axios) allows you to easily mock `axios`, a common HTTP client, in your tests. It works out of the box with Jest, and the author provides guidance on supporting other test runners in the documentation.