docs: fix formatting (#767)

Author: vuejs-jp-bot

src/v2/cookbook/unit-testing-vue-components.md

@@ -79,11 +79,11 @@ Component unit tests have lots of benefits:
 - Improve design
 - Facilitate refactoring
 
-Automated testing allows large teams of developers to maintain complex codebases. 
+Automated testing allows large teams of developers to maintain complex codebases.
 
 #### Getting started
 
-[vue-test-utils](https://github.com/vuejs/vue-test-utils) is the official library for unit testing Vue components. The (vue-cli)[https://github.com/vuejs/vue-cli] webpack template comes with either Karma or Jest, both well supported test runners, and there are some (guides)[https://vue-test-utils.vuejs.org/en/guides/] in the `vue-test-utils` documentation.
+[vue-test-utils](https://github.com/vuejs/vue-test-utils) is the official library for unit testing Vue components. The [vue-cli](https://github.com/vuejs/vue-cli) webpack template comes with either Karma or Jest, both well supported test runners, and there are some [guides](https://vue-test-utils.vuejs.org/en/guides/) in the `vue-test-utils` documentation.
 
 ## Real-World Example
 
@@ -92,11 +92,11 @@ Unit tests should be
 - Easy to understand
 - Only test a _single unit of work_
 
-Let's continue building on the previous example, while introducing the idea of a [factory function](https://en.wikipedia.org/wiki/Factory_(object-oriented_programming)) to make our test more compact and readable. The component should:
+Let's continue building on the previous example, while introducing the idea of a <a href="https://en.wikipedia.org/wiki/Factory_(object-oriented_programming)">factory function</a> to make our test more compact and readable. The component should:
 
 - show a 'Welcome to the Vue.js cookbook' greeting.
 - prompt the user to enter their username
-- if the entered username is less than seven letters, display an error
+- display an error if the entered username is less than seven letters
 
 Let's take a look at the component code first:
 
@@ -218,7 +218,7 @@ describe('Foo', () => {
 
 Points to note:
 
-At the top, we declare the factory function which merges the `values` object into `data` and returns a new `wrapper` instance. This way, we don't need to duplicate `const wrapper = shallow(Foo)` in every test. Another great benefit to this is when more complex components with a method or computed property you might want to mock or stub in every test, you only need to declare it once. 
+At the top, we declare the factory function which merges the `values` object into `data` and returns a new `wrapper` instance. This way, we don't need to duplicate `const wrapper = shallow(Foo)` in every test. Another great benefit to this is when more complex components with a method or computed property you might want to mock or stub in every test, you only need to declare it once.
 
 ## Additional Context
 
@@ -230,13 +230,13 @@ Thee above test is fairly simple, but in practise Vue components often have othe
 
 There are more complete examples showing such tests in the `vue-test-utils` [guides](https://vue-test-utils.vuejs.org/en/guides/).
 
-`vue-test-utils` and the enormous JavaScript ecosystem provides plenty of tooling to facilitate almost 100% test coverage. Unit tests are only one part of the testing pyramid, though. Some other types of tests include e2e (end to end) tests, and snapshot tests. Unit tests are the smallest and most simple of tests - they make assertions on the smallest units of work, isolating each part of a single component. 
+`vue-test-utils` and the enormous JavaScript ecosystem provides plenty of tooling to facilitate almost 100% test coverage. Unit tests are only one part of the testing pyramid, though. Some other types of tests include e2e (end to end) tests, and snapshot tests. Unit tests are the smallest and most simple of tests - they make assertions on the smallest units of work, isolating each part of a single component.
 
 Snapshot tests save the markup of your Vue component, and compare to the new one generated each time the test runs. If something changes, the developer is notified, and can decide if the change was intentional (the component was updated) or accidentally (the component is behaving incorrectly).
 
 End to end tests involve ensure a number of components interact together well. They are more high level. Some examples might be testing if a user can sign up, log in, and update their username. These are slowly to run than unit tests or snapshot tests.
 
-Unit tests are most useful during development, either to help a developer think about how to design a component, or refactor an existing component, and are often run every time code is changed. 
+Unit tests are most useful during development, either to help a developer think about how to design a component, or refactor an existing component, and are often run every time code is changed.
 
 Higher level tests, such as end to end tests, run much slower. These usually run pre-deploy, to ensure each part of the system is working together correctly.