RedHatTraining/rht-labs-docs.git

ADD - Big Picture components and fix a typo

donal

2018-07-03 1a8071fbaa5d256f7582b00bc437e90bc7b6e4d2

commit \| author \| age
15c296	1	# Revenge Of The Automated Testing
5a16fd	2
867471	3	> The purpose of this exercise is to develop and validate a new feature using TDD; and to promote the assured feature through the pipeline.
01245c	4
9e07af	5	![comic-header](../images/exercise3/comic-header.png)
RH	6
	7	[Image Source](https://cdn-images-1.medium.com/max/1600/1*wF_fSCH-gLYfMbkwb3gR2w.png)
	8
aea5c5	9	## Introduction to TDD.
D	10
	11	> _Here is a brief introduction of TDD and why we use it._
	12
	13	Test Driven Development (TDD) is a software development process that relies on the repetition of a very short development cycle. Requirements are turned into test cases, where the software is developed to pass the tests. In other words, it creates a safety net that serves to keep the developer's problems/bugs at bay while enabling the developer to refactor efficiently. This is opposed to software development that allows software to be added that is not proven to meet requirements.
	14
	15	The TDD cycle can be illustrated with the following diagram;
	16	![TDD-diagram](../images/exercise3/TDD-lifecycle.jpg)
	17
5e7a31	18	### The TDD Cycle
aea5c5	19
D	20	1. `Write a test` -
853f0c	21	In TDD a new feature begins by writing a test. Write a test that clearly defines a function or one that provides an improvement to an existing function. It's important the developer clearly understands the feature's specification and requirements, or the feature could be wrong from the get-go.
aea5c5	22
D	23	2. `Test Fails` -
5e7a31	24	When a test is first implemented it is expected to fail. This failure validates the test is working correctly as the feature is yet to be implemented.
aea5c5	25
D	26	3. `Write code to make test pass` -
	27	This step involves implementing the feature to pass the failed test. Code written at this stage may be inelegant and still pass the test, however this is acceptable as TDD is a recursive cycle which includes code refactoring.
	28
	29	4. `Code Passes tests` -
	30	If all tests pass, the developer can be confident that the new code meets the test requirements.
	31
	32	5. `Refactor` -
f23c14	33	The refactoring step will allow the developer to clean up their code without changing its behaviour. Not changing the behaviour should ensure the tests still pass. The process of refactoring can include; removal of duplication, renaming of object, class, module, variable and method names to clearly represent their current purpose and use, decoupling of functionality and increasing code cohesion.
aea5c5	34
D	35	6. `Repeat` -
	36	Starting with another new test, the cycle is then repeated to push forward the functionality. The size of the steps should always be small, with as few as 1 to 10 edits between each test run. If new code does not rapidly satisfy a new test, or other tests fail unexpectedly, the programmer should undo or revert in preference to excessive debugging.
	37
	38	### Testing Bananalogy
5e7a31	39	Explanation of Mocha and JS test syntax through Bananalogy! Imagine for a moment; we're not building software but creating a bowl of fruit. To create a `Bunch of Bananas` component for our fruit bowl we could start with our tests as shown below.
aea5c5	40	![bdd-bananas](../images/exercise3/bdd-bananas.png)
D	41	* `describe` is used to group tests together. The string `"a bunch of ripe bananas"` is for human reading and allows you to identify tests.
	42	* `it` is a statement that contains a test. It should contain an assertion such as `expect` or `should`. It follows the syntax of `describe` where the string passed in identifies the statement.
01245c	43
D	44	---
5a16fd	45
D	46	## Learning Outcomes
01245c	47
5a16fd	48	As a learner you will be able to
01245c	49
142de4	50	* Understand the why behind TDD
936424	51	* Implement a feature using TDD for front end and backend
142de4	52	* Write end to end tests for the feature and run them in CI
5a16fd	53
D	54	## Tools and Frameworks
01245c	55
5a16fd	56	> Name of tool - short description and link to docs or website
D	57
142de4	58	1. [Jest](https://facebook.github.io/jest/) - Zero configuration testing platform
D	59	Jest is used by Facebook to test all JavaScript code including React applications. One of Jest's philosophies is to provide an integrated "zero-configuration" experience. We observed that when engineers are provided with ready-to-use tools, they end up writing more tests, which in turn results in more stable and healthy code bases.
	60	1. [Vue Test Utils](https://vue-test-utils.vuejs.org/en/) - Vue Test Utils is the official unit testing utility library for Vue.js.
	61	1. [Nightwatch.js](http://nightwatchjs.org/) - Nightwatch.js is an easy to use Node.js based End-to-End (E2E) testing solution for browser based apps and websites. It uses the powerful W3C WebDriver API to perform commands and assertions on DOM elements.
	62	1. [Mocha](https://mochajs.org/) - Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. Mocha tests run serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases. Hosted on GitHub.
5e7a31	63	1. [Sinon](http://sinonjs.org/) - Standalone test spies, stubs and mocks for JavaScript.
142de4	64	Works with any unit testing framework.
5a16fd	65
D	66	## Big Picture
1a8071	67	> From the previous exercise; we created a simple pipeline. We will now flesh it out with some testing to add gates to our pathway to production.
01245c	68
1a8071	69	![big-picture](../images/big-picture/big-picture-3.jpg)
5a16fd	70
01245c	71	---
5a16fd	72
D	73	## 10,000 Ft View
	74
a9efee	75	> The goal of this exercise is to add a new component to the application using TDD to create and validate its behaviour. The User story we have been given is as follows:
5a16fd	76
5e7a31	77	As a doer I want to mark todos as important so that I can keep track of and complete high priority todos first
01245c	78
142de4	79	_Acceptance Criteria_
D	80	- [ ] should be doable with a single click
	81	- [ ] should add a red flag against the todo when marked important
	82	- [ ] should remove the red colour flag on the flag when important removed
	83	- [ ] should not affect existing todos
	84
	85	_On page load:_
	86	- [ ] should display existing todos that are not marked important
	87	- [ ] should display existing todos that are marked important with an red flag
5a16fd	88
D	89	## Step by Step Instructions
3050f4	90	> This is a fairly structured guide with references to exact filenames and sections of text to be added.
5a16fd	91
01245c	92	### Part 1 - Tests in our Pipeline
936424	93	> _In this part we will get familiar with the layout of our tests. We will also improve the pipeline created already by adding some unit tests for the front end & backend along with some end to end tests (e2e) to validate the full solution_
5a16fd	94
752f2a	95	#### 1a - FE Unit tests
936424	96	> In this exercise we will execute our test for the front end locally. Once verified we will add them to Jenkins.
d1565e	97
1a8071	98	1. Before linking our automated testing to the pipeline we'll first ensure the tests run locally. Change to the `todolist-fe` directory and run `test`.
3050f4	99	```bash
58480f	100	cd todolist-fe
D	101	```
	102	```bash
	103	npm run test
3050f4	104	```
5e7a31	105	<p class="tip" >
8fc8df	106	`test` is an alias used that runs `vue-cli-service test` from the scripts object in `package.json`
3050f4	107	</p>
aea5c5	108	![screenshot-scripts](../images/exercise3/screenshot-scripts.png)
D	109
936424	110	2. This command will run all `spec.js` files. Our test files are stored in the following places. There are 12 front end test files stored in these directories: `todolist-fe/tests/unit/vue-components/` & `todolist-fe/tests/unit/javascript/*`
d1565e	111
3050f4	112	2. You should see an output similar to the following. The above command has run a test suite for every `*.spec.js` file. The table generated in the terminal shows the code coverage. We're going to be focusing on the unit tests for now.
aea5c5	113	![test-run-locally](../images/exercise3/test-run-locally.png)
3050f4	114
5e7a31	115	2. Repeat the same process for `todolist-api` and verify that all the tests run. If you have an ExpressJS server already running from previous exercise; you should kill it before running the tests. The `mocha` test suite will launch a dev server for running the tests. There are 2 API test files: `todolist-api/server/api/todo/todo.spec.js` & `todolist-api/server/mocks/mock-routes.spec.js` for our API and the Mocks server.
3050f4	116	```bash
58480f	117	cd todolist-api
D	118	```
	119	```bash
	120	npm run test
3050f4	121	```
b81187	122
5e7a31	123	2. Navigate to your instance of Jenkins at `https://jenkins-<YOUR_NAME>-ci-cd.apps.lader.rht-labs.com/`.
3050f4	124	Click on `dev-todolist-fe-build` and then click the `configure` button on the left-hand side.
aea5c5	125	![jenkins-configure-job](../images/exercise3/jenkins-configure-job.png)
3050f4	126
140a4a	127	2. Scroll to the `Build` part of the configuration page and add `npm run test` below `npm install`.
aea5c5	128	![jenkins-build-step](../images/exercise3/jenkins-build-step.png)
3050f4	129
e1ba4f	130	2. Scroll to the `Post-build Actions` section and click `Add post-build action`. Select `Publish xUnit test result report` (Jenkins might place this at the top of the `Post-build Actions` list).
aea5c5	131	![xunit-action](../images/exercise3/xunit-action.png)
b81187	132
A	133	2. Click the `Add` button under `Publish xUnit test result report` and select `JUnit`. In the pattern field enter `test-report.xml`. In the `Failed Tests Thresholds` input box enter 0 under `Red Ball Total`. It should look a little something like this:
aea5c5	134	![post-build-actions](../images/exercise3/post-build-actions.png)
b81187	135
0976ea	136	2. Click `save` or `apply` at the bottom to save the changes. Run the `dev-todolist-fe-build` job and verify that this passes and the `build` and `bake` jobs are both triggered.
b81187	137
a9627c	138	#### (Optional) Failing the tests
65ddc2	139	> _If you're not very confident in your technical ability and want don't want to do the TDD lab; feel free to just do this next section. If you are confident jump on to the e2e testing section below_
a9627c	140
d82125	141	2. We're now going to deliberately fail a test to ensure that `bake` and `deploy` jobs aren't triggered if any tests fail. Open the `todolist-fe` source code in your favourite editor. Open `ListOfTodos.spec.js` in `/tests/unit/vue-components` and head to `line 39`. Add `not.` before `toHaveBeenCalled()` to fail the test.
aea5c5	142	![change-test-to-fail](../images/exercise3/change-test-to-fail.png)
b81187	143
0976ea	144	2. Push this to Gitlab and run the build job.
b81187	145	```bash
58480f	146	git add .
D	147	```
	148	```bash
	149	git commit -m "TEST - failing build with tests"
	150	```
	151	```bash
	152	git push
b81187	153	```
A	154
5e7a31	155	2. Rerun the `dev-todolist-fe-build` job. It should have failed and not run any other jobs.
aea5c5	156	![jenkins-with-failing-build](../images/exercise3/jenkins-with-failing-build.png)
b81187	157
5da0fd	158	2. You can examine the test results on the jobs home page. Drill down into the tests to see which failed and other useful stats
D	159	![fe-test-fails](../images/exercise3/fe-test-fails.png)
	160
ff561b	161	2. Undo the changes you made to the `ListOfTodos.spec.js` file, commit your code and rerun the build. This should trigger a full `build --> bake --> deploy` of `todolist-fe`.
e1ba4f	162
a9627c	163	#### 1b - End to End tests (e2e)
cad21a	164	> _Unit tests are a great way to get immediate feedback as part of testing an application. End to end tests that drive user behaviour are another amazing way to ensure an application is behaving as expected._
d1565e	165
f9d113	166	In this exercise we will add a new stage to our pipeline called `dev-todolist-fe-e2e` that will run after the deploy has been completed. End to end tests will use Nightwatchjs to orchestrate a selenium webdriver instance that controls the web browser; in this case Chrome!
D	167
	168	2. Let's start by checking our tests execute locally. On the terminal move to the `todolist-fe` folder. Our end to end tests are stored in `tests/e2e/specs/`. The vuejs cli uses nightwatch and comes pre-configured to run tests against Chrome. We have created some additional configuration in the root of the project `nightwatch.config.js` to run headless in CI mode on Jenkins.
	169	```bash
58480f	170	cd todolist-fe
f9d113	171	```
D	172
	173	2. Run the tests locally by executing the following. This should start the dev server and run the test. You may see the browser pop up and close while tests execute.
	174	```bash
58480f	175	npm run e2e
f9d113	176	```
4ce512	177	![local-e2e](../images/exercise3/local-e2e.png)
f9d113	178
4ce512	179	2. With tests executing locally; let's add them to our Jenkins pipeline. To do this; we'll create a new job and connect it up to our `todolist-fe` jobs. Open Jenkins and create a `New Item` called `dev-todolist-fe-e2e`. Make this Job `Freestyle`.
f9d113	180
e1ba4f	181	2. On the configuration page (under the general tab); Set the Label for the job to run on as `jenkins-slave-npm`. Check the box marking the build parameterised and add a String parameter of `BUILD_TAG` as done before
4ce512	182	![e2e-general](../images/exercise3/e2e-general.png)
d1565e	183
4ce512	184	2. On the Source Code Management tab; set the source code to git and add the url to your `todolist-fe` app. Set the branch to `refs/tags/${BUILD_TAG}`
D	185	![e2e-git](../images/exercise3/e2e-git.png)
	186
e1ba4f	187	2. Set `Color ANSI Console Output` on the `Build Environment` section
4ce512	188
45eb81	189	2. On the Build section; add a build step to execute shell and fill in the following substituting `<YOUR_NAME>` accordingly:
4ce512	190	```bash
45eb81	191	export E2E_TEST_ROUTE=todolist-fe-<YOUR_NAME>-dev.apps.lader.rht-labs.com
7a3088	192	npm install
D	193	npm run e2e:ci
4ce512	194	```
D	195	![e2e-steps](../images/exercise3/e2e-steps.png)
	196
e1ba4f	197	2. Add a Post Build action to `Publish Junit test result report`. Add `reports/e2e/specs/*.xml` to the report location and save the configuration to be brought back to the Job's homepage.
4ce512	198	![e2e-post-build](../images/exercise3/e2e-post-build.png)
D	199
e1ba4f	200	2. We want to connect the e2e job we just created to our dev pipleline by editing the post build actions on `dev-todolist-fe-deploy` job. Open the `dev-todolist-fe-deploy` job and hit `configure`. In the `Post-build actions` section of this job add a `Trigger parameterised build` on other jobs. Set the `Projects to build` to be `dev-todolist-fe-e2e`. Add a Parameter and set the it to the `Current build parameters`. Save the settings.
a47ec2	201	![e2e-trigger](../images/exercise3/e2e-trigger.png)
D	202
b62fab	203	2. Run the pipeline from the beginning to see the tests executed (two executions will show tests scores on the graph!).
d1565e	204
142de4	205	### Part 2 - TodoList new feature
d1565e	206	> _In this exercise we will introduce a new feature to create an important flag on the todos. In order to be able to build and test our feature we will use TDD_
D	207
142de4	208	As a doer I want to mark todos as important so that I can keep track of and complete high prirority todos first
d1565e	209
142de4	210	_Acceptance Criteria_
D	211	- [ ] should be doable with a single click
	212	- [ ] should add a red flag against the todo when marked important
	213	- [ ] should remove the red colour flag on the flag when important removed
	214	- [ ] should not affect existing todos
d1565e	215
142de4	216	_On page load:_
D	217	- [ ] should display existing todos that are not marked important
	218	- [ ] should display existing todos that are marked important with an red flag
d1565e	219
752f2a	220	#### 2a - Create todolist-api tests
142de4	221	> Using [Mocha](https://mochajs.org/) as our test runner; we will now write some tests for backend functionality to persist our important-flag. The changes required to the backend are minimal but we will use TDD to create our test first, then implement the functionality.
01245c	222
D	223	3. Create a new branch in your `todolist-api` app for our feature and push it to the remote
d1565e	224	```bash
58480f	225	git checkout -b feature/important-flag
D	226	```
	227	```bash
	228	git push -u origin feature/important-flag
5a16fd	229	```
D	230
01245c	231	3. Navigate to the `server/api/todo/todo.spec.js` file. This contains all of the existing todo list api tests. These are broken down into simple `describe("api definition", function(){})` blocks which is BDD speak for how the component being tested should behave. Inside of each `it("should do something ", function(){})` statements we use some snappy language to illustrate the expected behaviour of the test. For example a `GET` request of the api is described and tested for the return to be of type Array as follows.
D	232	```javascript
	233	describe("GET /api/todos", function() {
	234	it("should respond with JSON array", function(done) {
	235	request(app)
	236	.get("/api/todos")
	237	.expect(200)
	238	.expect("Content-Type", /json/)
	239	.end(function(err, res) {
	240	if (err) return done(err);
	241	// Test goes here
	242	res.body.should.be.instanceof(Array);
	243	done();
	244	});
142de4	245	});
01245c	246	});
D	247	```
	248	where:
775c6b	249	- `describe` is used to group tests together into a collection asserting some feature; for example the get all todos api.
D	250	- `it` is an individual test statement and should contain an `expect` or a `should` statement asserting behaviour of the API under test.
	251	- `request` is a library for making http calls to the api.
	252	- `.expect(200)` asserts the HTTP Return Code
	253	- `res.body.should.be.instanceof(Array);` is the actual test call
	254	- `done();` tells the test runner that `mocha` has finished execution. This is needed as the http calls are asynchronous.
5a16fd	255
5e7a31	256	3. With this knowledge; let's implement our test for the `important` flag. We expect the front end to introduce a new property on each `todo` that gets passed to the backend called `important`. The API will need to handle this new property and pass it into the mongodb. Let's begin implementing this functionality by writing our test case. Navigate to the `PUT /api/todos` section of the `server/api/todo/todo.spec.js` test file (which should be at the bottom)
775c6b	257	![todo-api-tests](../images/exercise3/todo-api-tests.png)
01245c	258
775c6b	259	3. Before writing our test; let's first make sure all the existing tests are passing.
142de4	260	```bash
58480f	261	npm run test
01245c	262	```
D	263
775c6b	264	3. With all the tests passing; let's add our new one. For ease of completing this exercise a template of a new test has been written at the very end of the file (just below the ` // Exercise 3 test case!` comment). A PUT request responds in our API with the data that it has just updated. So provided that MongoDB accepted the change, the API will respond with an object that has the `important` property on it. To write our test; edit the template test by completing the following:
9f3a7a	265	* Edit the `it("should ...")` to describe the important flag we're testing
01245c	266	* Edit the `.send()` to include `important: true` property
775c6b	267	* Edit the `.expect()` to be `.expect(200)`
01245c	268	* Add a new test assertion to check that `res.body.important` is `true` below the `// YOUR TEST GO HERE` line.
D	269	```javascript
775c6b	270	// Exercise 3 test case!
142de4	271	it("should mark todo as important and persist it", function(done) {
01245c	272	request(app)
D	273	.put("/api/todos/" + todoId)
142de4	274	.send({
D	275	title: "LOVE endpoint/server side testing!",
	276	completed: true,
	277	important: true
	278	})
01245c	279	.expect(200)
D	280	.expect("Content-Type", /json/)
	281	.end(function(err, res) {
142de4	282	if (err) return done(err);
D	283	res.body.should.have.property("_id");
	284	res.body.title.should.equal("LOVE endpoint/server side testing!");
	285	// YOUR TEST GO HERE
	286	res.body.important.should.equal(true);
	287	done();
01245c	288	});
142de4	289	});
01245c	290	```
D	291
142de4	292	3. Run your test. It should fail.
D	293	```bash
58480f	294	npm run test
01245c	295	```
D	296	![fail-mocha](../images/exercise3/fail-mocha.png)
	297
9f3a7a	298	3. With our test now failing; let's implement the feature. This is quite a simple change - we first need to update the `server/api/todo/todo.model.js`. Add an additional property on the schema called `important` and make its type Boolean.
01245c	299	```javascript
D	300	const TodoSchema = new Schema({
142de4	301	title: String,
D	302	completed: Boolean,
	303	important: Boolean
01245c	304	});
D	305	```
9f3a7a	306
5e7a31	307	3. Next we need to update the `server/config/seed.js` file so that the pre-generated todos have an important property. Add `important: true` below `completed: ` for each object. Don't forget to add a comma at the end of the `completed: ` line.
9f3a7a	308	![api-add-seed-important](../images/exercise3/api-add-seed-important.png)
01245c	309
142de4	310	3. With your changes to the Database schema updated; re-run your tests.
D	311	```bash
58480f	312	npm run test
01245c	313	```
D	314
142de4	315	3. Commit your code to the `feature/important-flag` branch and then merge onto the `develop` branch as follows
01245c	316	<p class="tip">
D	317	NOTE - At this point in a residency we would peer review the code before pushing it to develop or master branch!
	318	</p>
142de4	319	```bash
58480f	320	git add .
D	321	```
	322	```bash
	323	git commit -m "ADD backend schema updates"
	324	```
	325	```bash
	326	git push
	327	```
	328	```bash
	329	git checkout develop
	330	```
	331	```bash
	332	git merge feature/important-flag
	333	```
	334	```bash
	335	git push
01245c	336	```
D	337
1329f3	338	3. After pushing your changes; start back up the `todolist-api` app on a new terminal session
D	339	```bash
58480f	340	npm run start
1329f3	341	```
D	342
936424	343	#### 2b - Create todolist-fe tests
5e7a31	344	> Using [Jest](https://facebook.github.io/jest/) as our test runner and the `vue-test-utils` library for managing our vue components; we will now write some tests for front end functionality to persist our important-flag. The changes required to the front end are quite large but we will use TDD to create our test first, then implement the functionality.
01245c	345
853f0c	346	Our TodoList App uses `vuex` to manage the state of the app's todos and `axios` HTTP library to connect to the backend. `Vuex` is an opinionated framework for managing application state and has some key design features you will need to know to continue with the exercise.
01245c	347
a9efee	348	In `vuex` the application state is managed by a `store`. The `store` houses all the todos we have retrieved from the backend as well as the `getter` methods for our array of `todos`. In order to make changes to the store, we could call the store directly and update each todo item but as earlier said; vuex is an opinionated module with its own way of updating the store. It is bad practice to call the store directly.
142de4	349
853f0c	350	There are two parts of the lifecycle to updating the store, the `actions` & `mutations`. When the user clicks a todo to mark it as complete; the `actions` are called. An action could involve a call to the backend or some pre-processing of the data. Once this is done, the change is committed to the store by calling the `mutation` function. A store should only ever be manipulated through a mutation function. Calling the mutation will then update the todo object in the app's local store for rendering in the view.
142de4	351
D	352	For example; when marking a todo as done in the UI, the following flow occurs
1329f3	353	* The `TodoItem.vue` calls the `markTodoDone()` function which dispatches an event to the store.
D	354	* This calls the `updateTodo()` function in the `actions.js` file
	355	* The action will update the backend db (calling our `todolist-api`) with our updated todo object.
	356	* The action will commit the change to the store by calling the mutation method `MARK_TODO_COMPLETED`
	357	* The `MARK_TODO_COMPLETED` will directly access the store object and update it with the new state value
	358	* The `ListOfTodos.vue` component is watching the store for changes and when something gets updated it re-renders the `TodoItem.vue`.
	359
	360	The implementation of our `important` flag will follow this same flow.
142de4	361
D	362	3. Let's implement our feature by first creating a branch. Our new feature, important flag will behave in the same way as the `MARK_TODO_COMPLETED`. Create a new branch in your `todolist-fe` app for our feature and push it to the remote
01245c	363	```bash
58480f	364	git checkout -b feature/important-flag
D	365	```
	366	```bash
	367	git push -u origin feature/important-flag
01245c	368	```
d1565e	369
5e7a31	370	3. Let's get our tests running by executing a `--watch` on our tests. This will keep re-running our tests everytime there is a file change. It is handy to have this running in a new terminal session.
142de4	371	```bash
58480f	372	npm run test -- --watch
142de4	373	```
D	374
1329f3	375	3. All the tests should be passing when we begin. If `No tests found related to files changed since last commit` is on show; hit `a` on the terminal to re-run `all` tests.
D	376	![rerun-all](../images/exercise3/rerun-all.png)
	377
867471	378	3. There are three places we will add new tests to validate our function behaves as expected against the acceptance criteria from the Feature Story supplied to us. We will need to write tests for our `TodoItem.vue` to handle having a red flag and that it is clickable. Our app is going to need to persist the changes in the backend so we'll want to make changes to our `actions.js` and `mutations.js` to keep the api and local copy of the store in sync. Let's start with our `TodoItem.vue` component. Open the `tests/unit/vue-components/TodoItem.spec.js` file. This has been templated with some example test to correspond with our A/Cs for speed of doing the exercise. Find the describe block for our important flag tests. It is setup already with a `beforeEach()` hook for test setup.
142de4	379	![important-flag-before](../images/exercise3/important-flag-before.png)
D	380
a9efee	381	3. Each of our test cases has its skeleton in place already for example the `TodoItem.vue` component takes a property of `todos` when rendering. This setup is already done for each of our tests so all we have to do is fill in our assertions.
142de4	382	![todoitem-skeleton-tests](../images/exercise3/todoitem-skeleton-tests.png)
D	383
1329f3	384	3. Let's implement the first test `it("should render a button with important flag"`. This test will assert if the button is present on the page and it contains the `.important-flag` CSS class. To implement this; add the `expect` statement as follows below the `// TODO - test goes here!` comment.
142de4	385	```javascript
D	386	it("should render a button with important flag", () => {
	387	const wrapper = mount(TodoItem, {
	388	propsData: { todoItem: importantTodo }
	389	});
	390	// TODO - test goes here!
	391	expect(wrapper.find(".important-flag").exists()).toBe(true);
	392	});
	393	```
	394
	395	3. Save the file and we should see in our test watch the test case has started failing because we have not yet implemented the feature!
	396	![todoitem-fail-test](../images/exercise3/todoitem-fail-test.png)
	397
9f3a7a	398	3. With a basic assertion in place, let's continue on to the next few tests. We want the important flag to be red when an item in the todolist is marked accordingly. Conversely we want it to be not red when false. Let's create a check for `.red-flag` CSS property to be present when important is true and not when false. Complete the `expect` statements in your test file as shown below for both tests.
142de4	399	```javascript
D	400	it("should set the colour to red when true", () => {
	401	const wrapper = mount(TodoItem, {
	402	propsData: { todoItem: importantTodo }
	403	});
	404	// TODO - test goes here!
	405	expect(wrapper.find(".red-flag").exists()).toBe(true);
	406	});
	407	it("should set the colour to not red when false", () => {
	408	importantTodo.important = false;
	409	const wrapper = mount(TodoItem, {
	410	propsData: { todoItem: importantTodo }
	411	});
	412	// TODO - test goes here!
	413	expect(wrapper.find(".red-flag").exists()).toBe(false);
	414	});
	415	```
	416
4c8a9b	417	3. Finally, we want to make the flag clickable and for it to call a function to update the state. The final test in the `TodoItem.spec.js` we want to create should simulate this behaviour. Implement the `it("call markImportant when clicked", () ` test by first simulating the click of our important-flag and asserting the function `markImportant()` to write is executed.
142de4	418	```javascript
4c8a9b	419	it("call markImportant when clicked", () => {
142de4	420	const wrapper = mount(TodoItem, {
D	421	methods,
	422	propsData: { todoItem: importantTodo }
	423	});
	424	// TODO - test goes here!
	425	const input = wrapper.find(".important-flag");
	426	input.trigger("click");
	427	expect(methods.markImportant).toHaveBeenCalled();
	428	});
	429	```
	430
1329f3	431	3. With our tests written for the feature's UI component, let's implement our code to pass the tests. Explore the `src/components/TodoItem.vue`. Each vue file is broken down into 3 sections
142de4	432	* The `<template></template>` contains the HTML of our component. This could include references to other Components also
D	433	* The `<script></script>` contains the JavaScript of our component and is essentially the logic for our component. It defines things like `properties`, `methods` and other `components`
	434	* The `<style></style>` contains the encapsulated CSS of our component
1329f3	435
853f0c	436	3. Underneath the `</md-list-item>` tag, let's add a new md-button. Add an `.important-flag` class on the `md-button` and put the svg of the flag provided inside it.
142de4	437	```html
D	438	</md-list-item>
867471	439	<!-- TODO - SVG for use in Exercise3 -->
142de4	440	<md-button class="important-flag">
D	441	<svg height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg" ><path d="M0 0h24v24H0z" fill="none"/><path d="M14.4 6L14 4H5v17h2v-7h5.6l.4 2h7V6z"/></svg>
	442	</md-button>
	443	```
	444
	445	3. We should now see the first of our failing tests has started to pass. Running the app locally (using `npm run serve`) should show the flag appear in the UI. It is clickable but won't fire any events and the colour is not red as per our requirement. Let's continue to implement the colour change for the flag. On our `<svg/>` tag, add some logic to bind the css to the property of a `todo.important` by adding ` :class="{'red-flag': todoItem.important}" `. This logic will apply the CSS class when `todo.important` is true.
	446	```html
	447	<md-button class="important-flag">
	448	<svg :class="{'red-flag': todoItem.important}" height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg" ><path d="M0 0h24v24H0z" fill="none"/><path d="M14.4 6L14 4H5v17h2v-7h5.6l.4 2h7V6z"/></svg>
	449	</md-button>
	450	```
	451
853f0c	452	3. More tests should now be passing. Let's wire the click of the flag to an event in Javascript. In the methods section of the `<script></script>` tags in the Vue file, implement the `markImportant()`. We want to wire this to the action to updateTodo, just like we have in the `markCompleted()` call above it. We also need to pass an additional property to this method called `important`
142de4	453	```javascript
D	454	markImportant() {
867471	455	// TODO - FILL THIS OUT IN THE EXERCISE
142de4	456	this.$store.dispatch("updateTodo", {id: this.todoItem._id, important: true});
D	457	console.info("INFO - Mark todo as important ", this.todoItem.important);
	458	},
	459	```
	460
853f0c	461	3. Let's connect the click button in the DOM to the Javascript function we've just created. In the template, add a click handler to the md-button to call the function `markImportant()` by adding ` @click="markImportant()"` to the `<md-button>` tag
142de4	462	```html
867471	463	<!-- TODO - SVG for use in Exercise3 -->
142de4	464	<md-button class="important-flag" @click="markImportant()">
D	465	<svg :class="{'red-flag': todoItem.important}" height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg" ><path d="M0 0h24v24H0z" fill="none"/><path d="M14.4 6L14 4H5v17h2v-7h5.6l.4 2h7V6z"/></svg>
	466	</md-button>
	467	```
9f3a7a	468
A	469	3. Finally - we need to make it so that when a new todo item is created it will have an important property. Head to `store/actions.js` and add `important: false` below `completed: false` in the `addTodo(){}` action.
	470	![fe-add-actions-important](../images/exercise3/fe-add-actions-important.png)
	471
142de4	472
5e7a31	473	3. The previously failing tests should have started to pass now. With this work done, let's commit our code. On the terminal, run
142de4	474	```bash
58480f	475	git add .
D	476	```
	477	```bash
	478	git commit -m "Implementing the todoitem flag"
	479	```
	480	```bash
	481	git push
142de4	482	```
D	483
3ee499	484	3. Open our local todolist app (http://localhost:8080/#/todo). If we try to use our important flag, we should see it's still not behaving as expected; this is because we're not updating the state of the app in response to the click event.
D	485
	486	3. We need to implement the `actions` and `mutations` for our feature. Let's start with the tests. Open the `tests/unit/javascript/actions.spec.js` and navigate to the bottom of the file. Our action should should commit the `MARK_TODO_IMPORTANT` to the mutations. Scroll to the end of the test file and implement the skeleton test by adding `expect(commit.firstCall.args[0]).toBe("MARK_TODO_IMPORTANT");` as the assertion.
142de4	487	```javascript
D	488	it("should call MARK_TODO_IMPORTANT", done => {
	489	const commit = sinon.spy();
	490	state.todos = todos;
	491	actions.updateTodo({ commit, state }, { id: 1, important: true }).then(() => {
	492	// TODO - test goes here!
	493	expect(commit.firstCall.args[0]).toBe("MARK_TODO_IMPORTANT");
	494	done();
	495	});
	496	});
	497	```
	498
7d4ccd	499	3. We should now have more failing tests, let's fix this by adding the call from our action to the mutation method. Open the `src/store/actions.js` file and scroll to the bottom to the `updateTodo()` method. Complete the if block by adding `commit("MARK_TODO_IMPORTANT", i);` as shown below.
142de4	500	```javascript
D	501	updateTodo({ commit, state }, { id, important }) {
	502	let i = state.todos.findIndex(todo => todo._id === id);
	503	if (important) {
9f3a7a	504	// TODO - add commit important here!
142de4	505	commit("MARK_TODO_IMPORTANT", i);
D	506	} else {
	507	commit("MARK_TODO_COMPLETED", i);
	508	}
	509	```
	510
853f0c	511	3. Finally, let's implement the `mutation` for our feature. Again, starting with the tests... Open the `tests/unit/javascript/mutations.spec.js` to find our skeleton tests at the bottom of the file. Our mutation method is responsible for toggling the todo's `important` property between `true` and `false`. Let's implement the tests for this functionality by setting important to be true and calling the method expecting the inverse. Then let's set it to false and call the method expecting the inverse. Add the expectations below the `// TODO - test goes here!` comment as done previously.
142de4	512	```javascript
D	513	it("it should MARK_TODO_IMPORTANT as false", () => {
	514	state.todos = importantTodos;
	515	// TODO - test goes here!
	516	mutations.MARK_TODO_IMPORTANT(state, 0);
	517	expect(state.todos[0].important).toBe(false);
	518	});
	519
	520	it("it should MARK_TODO_IMPORTANT as true", () => {
	521	state.todos = importantTodos;
	522	// TODO - test goes here!
	523	state.todos[0].important = false;
	524	mutations.MARK_TODO_IMPORTANT(state, 0);
	525	expect(state.todos[0].important).toBe(true);
	526	});
	527	```
	528
e1ba4f	529	3. With our tests running and failing, let's implement the feature to their spec. Open the `src/store/mutations.js` and add another function called `MARK_TODO_IMPORTANT` below the `MARK_TODO_COMPLETED` to toggle `todo.important` between true and false. NOTE - add a `,` at the end of the `MARK_TODO_COMPLETED(){}` function call.
142de4	530	```javascript
D	531	MARK_TODO_IMPORTANT(state, index) {
	532	console.log("INFO - MARK_TODO_IMPORTANT");
	533	state.todos[index].important = !state.todos[index].important;
	534	}
	535	```
3ee499	536	![mark-todo-important](../images/exercise3/mark-todo-important.png)
142de4	537
e1ba4f	538	3. All our tests should now be passing. On the watch tab where they are running, hit `a` to re-run all tests and update any snapshots with `u` if needed.
142de4	539
D	540	3. With all our tests now passing, let's commit our code. On the terminal, run
	541	```bash
58480f	542	git add .
D	543	```
	544	```bash
	545	git commit -m "Implementing the store and actions"
	546	```
	547	```bash
	548	git push
142de4	549	```
D	550
5965fd	551	3. Before running a build in Jenkins, let's add our tests and code to the develop branch. Ask your neighbour to review your code changes and if they approve; merge them to Develop! (If you're feeling adventurous - raise a PR through GitLab and have someone on your desk peer review it!)
142de4	552	<p class="tip">
D	553	NOTE - At this point in a residency we would peer review the code before pushing it to develop or master branch!
	554	</p>
	555	```bash
58480f	556	git checkout develop
D	557	```
	558	```bash
	559	git merge feature/important-flag
	560	```
	561	```bash
	562	git push --all
142de4	563	```
D	564
3ee499	565	3. Run a build in Jenkins. If all things were successful; our application should be deployed as expected! Validate the flag is working as expected.
D	566	![todolist-important](../images/exercise3/todolist-important.png)
d1565e	567
752f2a	568	#### 2c - Create todolist e2e tests
d1565e	569
cf760d	570	> Using [Nightwatch.js](http://nightwatchjs.org/) We will write a reasonably simple e2e test to test the functionality of the feature we just implemented.
d6eb80	571
T	572	3. Firstly we need to create an e2e spec test file in the correct place.
	573
	574	```bash
	575	touch tests/e2e/specs/importantFlag.js
	576	```
	577
	578	3. Open this new file in your code editor and set out the initial blank template for an e2e test as below:
	579	![if-e2e-step1](../images/exercise3/if-e2e-step1.png)
	580
	581	3. Now get the test to access the todos page and wait for it to load. The url can be taken from `process.env.VUE_DEV_SERVER_URL`
	582	![if-e2e-step2](../images/exercise3/if-e2e-step2.png)
	583
	584	3. Now click the clear all button and then enter a value in the textbox to create a new item. We clear all first to ensure we start with a fresh list. We now do our first assertion: that a 'important flag' exists (the button to set important), and also that a red flag does not exist. You will quickly find there is no way to reference the clear all button. We will therefore have to go to `src/components/XofYItems.vue` and add `id="clear-all"` to the clear all button.
	585	![if-e2e-step3](../images/exercise3/if-e2e-step3.png)
	586	![if-e2e-step3a](../images/exercise3/if-e2e-step3a.png)
	587
	588	3. We should now get nightwatch to click the flag and check whether the flag has turned red.
	589	![if-e2e-step4](../images/exercise3/if-e2e-step4.png)
	590
	591	3. At this point we should have a working e2e test. We can run this by using `npm run e2e`. When satisfied we can push up these changes.
	592
	593	```bash
	594	git add .
	595	```
	596
	597	```bash
	598	git commit -m "Implementing e2e tests"
	599	```
	600
	601	```bash
	602	git push
	603	```
5a16fd	604
01245c	605	---
5a16fd	606
D	607	## Extension Tasks
01245c	608
5a16fd	609	> _Ideas for go-getters. Advanced topic for doers to get on with if they finish early. These will usually not have a solution and are provided for additional scope._
D	610
cad21a	611	* Add Config maps to inject DB creds to the app
D	612	* Create a blue/green deploy based on the success of running e2e tests against either blue or green and flopping load over to new endpoint when successful.
	613	Advanced
	614	* Add Auth0 support to your FE app.
5a16fd	615
D	616	## Additional Reading
01245c	617
5a16fd	618	> List of links or other reading that might be of use / reference for the exercise
D	619
	620	## Slide links
01245c	621
4f0295	622	- [Intro](https://docs.google.com/presentation/d/18W0GoBTwRGpgbOyHf2ZnL_OIWU_DvsoR14H0_t5jisA)
RH	623	- [Wrap-up](https://docs.google.com/presentation/d/1uIYHC57POSaVD6XNZGhdetABiSnlP1TztYTgglMP-DA)
5e7a31	624	- [All Material](https://drive.google.com/drive/folders/1xVaQukmwwmyJSDN0zOkghZX7yb-0freT)