RedHatTraining/rht-labs-docs.git

Rob Harris

2018-04-26 f23c14df25fa64258972796af8a2531f2725b4a8

commit \| author \| age
15c296	1	# Revenge Of The Automated Testing
5a16fd	2
142de4	3	> The purpose of this lab 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
	18	### The TDD Cycle
	19
	20	1. `Write a test` -
	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 features specification and requirements, or the feature could be wrong from the get-go.
	22
	23	2. `Test Fails` -
	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.
	25
	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
	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.
	40	![bdd-bananas](../images/exercise3/bdd-bananas.png)
	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
D	51	* Implement a feature using TDD for frontend and backend
	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.
	63	1. [Sinon](http://sinonjs.org/) - Standalone test spies, stubs and mocks for JavaScript.
	64	Works with any unit testing framework.
5a16fd	65
D	66	## Big Picture
01245c	67
5a16fd	68	This exercise begins cluster containing blah blah
D	69
01245c	70	---
5a16fd	71
D	72	## 10,000 Ft View
	73
142de4	74	> The goal of this exercise is to add a new component to the application using TDD to create and validate it's behaviour. The User story we have been given is as follows:
5a16fd	75
142de4	76	As a doer I want to mark todos as important so that I can keep track of and complete high prirority todos first
01245c	77
142de4	78	_Acceptance Criteria_
D	79	- [ ] should be doable with a single click
	80	- [ ] should add a red flag against the todo when marked important
	81	- [ ] should remove the red colour flag on the flag when important removed
	82	- [ ] should not affect existing todos
	83
	84	_On page load:_
	85	- [ ] should display existing todos that are not marked important
	86	- [ ] should display existing todos that are marked important with an red flag
5a16fd	87
D	88	## Step by Step Instructions
3050f4	89	> This is a fairly structured guide with references to exact filenames and sections of text to be added.
5a16fd	90
01245c	91	### Part 1 - Tests in our Pipeline
aea5c5	92	> _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 frontend & backend along with some end to end tests (e2e) to validate the full solution_
5a16fd	93
752f2a	94	#### 1a - FE Unit tests
e1ba4f	95	> In this exercise we will execute our test for the frontend locally. Once verified we will add them to Jenkins.
d1565e	96
655873	97	2. 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	98	```bash
A	99	$ cd todolist-fe
	100	$ npm run test
	101	```
	102	<p class="tip" >
8fc8df	103	`test` is an alias used that runs `vue-cli-service test` from the scripts object in `package.json`
3050f4	104	</p>
aea5c5	105	![screenshot-scripts](../images/exercise3/screenshot-scripts.png)
D	106
	107	2. This command will run all `spec.js` files. Our test files are stored in the following places. There are 12 Frontend test files stored in these directories: `todolist-fe/tests/unit/vue-components/` & `todolist-fe/tests/unit/javascript/*`
d1565e	108
3050f4	109	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	110	![test-run-locally](../images/exercise3/test-run-locally.png)
3050f4	111
204a7b	112	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	113	```bash
A	114	$ cd todolist-api
	115	$ npm run test
	116	```
b81187	117
a5f8e5	118	2. Navigate to your instance of jenkins at `https://jenkins-<YOUR_NAME>-ci-cd.apps.somedomain.com/`.
3050f4	119	Click on `dev-todolist-fe-build` and then click the `configure` button on the left-hand side.
aea5c5	120	![jenkins-configure-job](../images/exercise3/jenkins-configure-job.png)
3050f4	121
7a3088	122	2. Scroll to the `Build` part of the configuration page and add `npm run test` below `npm install`. Click `save` or `apply` at the bottom to save the changes.
aea5c5	123	![jenkins-build-step](../images/exercise3/jenkins-build-step.png)
3050f4	124
e1ba4f	125	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	126	![xunit-action](../images/exercise3/xunit-action.png)
b81187	127
A	128	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	129	![post-build-actions](../images/exercise3/post-build-actions.png)
b81187	130
0976ea	131	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	132
d82125	133	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	134	![change-test-to-fail](../images/exercise3/change-test-to-fail.png)
b81187	135
0976ea	136	2. Push this to Gitlab and run the build job.
b81187	137	```bash
A	138	$ git add .
d82125	139	$ git commit -m "TEST - failing build with tests"
b81187	140	$ git push
A	141	```
	142
e1ba4f	143	2. Rerun the `dev-todolist-fe-build` job. It should have failed and not run any other jobs.
aea5c5	144	![jenkins-with-failing-build](../images/exercise3/jenkins-with-failing-build.png)
b81187	145
5da0fd	146	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	147	![fe-test-fails](../images/exercise3/fe-test-fails.png)
	148
ff561b	149	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	150
752f2a	151	#### 1b - BE Unit tests
e1ba4f	152	> In this exercise we will execute our test for the backend locally. Once verified we will add them to Jenkins and add a mongodb to Jenkins for running tests there.
ff561b	153
55df0e	154	2. We're now going to do the same for the api. However, in order to run our API tests in CI; we need there to be a MongoDB available for testing. In our `enablement-ci-cd` repo; checkout the mongo branch as shown below to bring in the template and params. The mongodb template we're using is the same as the one for our `todolist-fe` created in previous lab.
D	155	```bash
	156	$ git checkout exercise3/mongodb params/mongodb templates/mongodb.yml
	157	```
ff561b	158
55df0e	159	2. Open `enablement-ci-cd` in your favourite editor. Edit the `inventory/host_vars/ci-cd-tooling.yml` to include a new object for our mongodb as shown below. This item can be added below the jenkins slave in the `ci-cd-builds` section.
D	160	```yaml
	161	- name: "jenkins-mongodb"
	162	namespace: "{{ ci_cd_namespace }}"
	163	template: "{{ playbook_dir }}/templates/mongodb.yml"
	164	params: "{{ playbook_dir }}/params/mongodb"
	165	tags:
	166	- mongodb
	167	```
	168	![jenkins-mongo](../images/exercise3/jenkins-mongo.png)
	169
	170	2. Git commit your updates to the inventory to git for traceability.
	171	```bash
	172	$ git add .
	173	$ git commit -m "ADD - mongodb for use in the pipeline"
	174	$ git push
	175	```
	176
	177	2. Apply this change as done previously using ansible. The deployment can be validated by going to your `<YOUR_NAME>-ci-cd` namespace!
	178	```bash
	179	$ ansible-playbook apply.yml -e target=tools \
	180	-i inventory/ \
	181	-e "filter_tags=mongodb"
	182	```
	183	![ocp-mongo](../images/exercise3/ocp-mongo.png)
	184
	185	2. With the mongodb in place Open up Jenkins and head to the `configure` panel of the `dev-todolist-api-build` job.
	186
7a3088	187	2. Add `npm run test:ci` above `npm run build:ci`.
aea5c5	188	![api-build-step](../images/exercise3/api-build-step.png)
ff561b	189
227301	190	2. Scroll to the `Post-build Actions` section and click `Add post-build action`. Select `Publish xUnit test result report`.
ff561b	191
e1ba4f	192	2. Click the `Add` button under `Publish xUnit test result report` and select `JUnit`. In the pattern field enter `reports/server/mocha/test-results.xml`. In the `Failed Tests Thresholds` input box enter 0 under `Red Ball Total`. It should look a little something like this. Save your changes:
aea5c5	193	![api-post-build](../images/exercise3/api-post-build.png)
ff561b	194
A	195	2. We're now going to deliberately fail a test again to ensure that `bake` and `deploy` jobs aren't triggered if any tests fail. Go to `todo.spec.js` in `/server/api/todo` and head to `line 35`. Replace `false` with `true`.
aea5c5	196	![api-fail-build](../images/exercise3/api-fail-build.png)
ff561b	197
0976ea	198	2. Push this to Gitlab and run the build job.
ff561b	199	```bash
A	200	$ git add .
d82125	201	$ git commit -m "TEST - failing build with tests"
ff561b	202	$ git push
A	203	```
	204
d82125	205	2. If successful this will fail the build and not run the `bake` or `deploy` jobs! Undo your changes and move on to the next section.
0976ea	206
A	207	<p class="tip">
	208	NOTE - Don't forget to undo the changes that you made to your tests!
	209	</p>
ff561b	210
752f2a	211	#### 1c - End to End tests (e2e)
cad21a	212	> _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	213
f9d113	214	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	215
	216	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.
	217	```bash
	218	$ cd todolist-fe
	219	```
	220
	221	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.
	222	```bash
	223	$ npm run e2e
	224	```
4ce512	225	![local-e2e](../images/exercise3/local-e2e.png)
f9d113	226
4ce512	227	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	228
e1ba4f	229	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	230	![e2e-general](../images/exercise3/e2e-general.png)
d1565e	231
4ce512	232	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	233	![e2e-git](../images/exercise3/e2e-git.png)
	234
e1ba4f	235	2. Set `Color ANSI Console Output` on the `Build Environment` section
4ce512	236
e1ba4f	237	2. On the Build section; add a build step to execute shell and fill in the following substituting `<YOUR_NAME>` and `somedomain` accordingly:
4ce512	238	```bash
8bf642	239	export E2E_TEST_ROUTE=todolist-fe-<YOUR_NAME>-dev.apps.somedomain.com
7a3088	240	npm install
D	241	npm run e2e:ci
4ce512	242	```
D	243	![e2e-steps](../images/exercise3/e2e-steps.png)
	244
e1ba4f	245	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	246	![e2e-post-build](../images/exercise3/e2e-post-build.png)
D	247
e1ba4f	248	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	249	![e2e-trigger](../images/exercise3/e2e-trigger.png)
D	250
b62fab	251	2. Run the pipeline from the beginning to see the tests executed (two executions will show tests scores on the graph!).
d1565e	252
142de4	253	### Part 2 - TodoList new feature
d1565e	254	> _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	255
142de4	256	As a doer I want to mark todos as important so that I can keep track of and complete high prirority todos first
d1565e	257
142de4	258	_Acceptance Criteria_
D	259	- [ ] should be doable with a single click
	260	- [ ] should add a red flag against the todo when marked important
	261	- [ ] should remove the red colour flag on the flag when important removed
	262	- [ ] should not affect existing todos
d1565e	263
142de4	264	_On page load:_
D	265	- [ ] should display existing todos that are not marked important
	266	- [ ] should display existing todos that are marked important with an red flag
d1565e	267
752f2a	268	#### 2a - Create todolist-api tests
142de4	269	> 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	270
D	271	3. Create a new branch in your `todolist-api` app for our feature and push it to the remote
d1565e	272	```bash
D	273	$ git checkout -b feature/important-flag
	274	$ git push -u origin feature/important-flag
5a16fd	275	```
D	276
01245c	277	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	278	```javascript
	279	describe("GET /api/todos", function() {
	280	it("should respond with JSON array", function(done) {
	281	request(app)
	282	.get("/api/todos")
	283	.expect(200)
	284	.expect("Content-Type", /json/)
	285	.end(function(err, res) {
	286	if (err) return done(err);
	287	// Test goes here
	288	res.body.should.be.instanceof(Array);
	289	done();
	290	});
142de4	291	});
01245c	292	});
D	293	```
	294	where:
775c6b	295	- `describe` is used to group tests together into a collection asserting some feature; for example the get all todos api.
D	296	- `it` is an individual test statement and should contain an `expect` or a `should` statement asserting behaviour of the API under test.
	297	- `request` is a library for making http calls to the api.
	298	- `.expect(200)` asserts the HTTP Return Code
	299	- `res.body.should.be.instanceof(Array);` is the actual test call
	300	- `done();` tells the test runner that `mocha` has finished execution. This is needed as the http calls are asynchronous.
5a16fd	301
775c6b	302	3. With this knowledge; let's implement our test for the `important` flag. We expect the fronted 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)
D	303	![todo-api-tests](../images/exercise3/todo-api-tests.png)
01245c	304
775c6b	305	3. Before writing our test; let's first make sure all the existing tests are passing.
142de4	306	```bash
01245c	307	$ npm run test
D	308	```
	309
775c6b	310	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	311	* Edit the `it("should ...")` to describe the important flag we're testing
01245c	312	* Edit the `.send()` to include `important: true` property
775c6b	313	* Edit the `.expect()` to be `.expect(200)`
01245c	314	* Add a new test assertion to check that `res.body.important` is `true` below the `// YOUR TEST GO HERE` line.
D	315	```javascript
775c6b	316	// Exercise 3 test case!
142de4	317	it("should mark todo as important and persist it", function(done) {
01245c	318	request(app)
D	319	.put("/api/todos/" + todoId)
142de4	320	.send({
D	321	title: "LOVE endpoint/server side testing!",
	322	completed: true,
	323	important: true
	324	})
01245c	325	.expect(200)
D	326	.expect("Content-Type", /json/)
	327	.end(function(err, res) {
142de4	328	if (err) return done(err);
D	329	res.body.should.have.property("_id");
	330	res.body.title.should.equal("LOVE endpoint/server side testing!");
	331	// YOUR TEST GO HERE
	332	res.body.important.should.equal(true);
	333	done();
01245c	334	});
142de4	335	});
01245c	336	```
D	337
142de4	338	3. Run your test. It should fail.
D	339	```bash
01245c	340	$ npm run test
D	341	```
	342	![fail-mocha](../images/exercise3/fail-mocha.png)
	343
9f3a7a	344	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	345	```javascript
D	346	const TodoSchema = new Schema({
142de4	347	title: String,
D	348	completed: Boolean,
	349	important: Boolean
01245c	350	});
D	351	```
9f3a7a	352
A	353	3. Next we need to update the `server/config/seed.js` file so that the pre-generated todos have an important propety. Add `important: true` below `completed: ` for each object. Don't forget to add a comma at the end of the `completed: ` line.
	354	![api-add-seed-important](../images/exercise3/api-add-seed-important.png)
01245c	355
142de4	356	3. With your changes to the Database schema updated; re-run your tests.
D	357	```bash
01245c	358	$ npm run test
D	359	```
	360
142de4	361	3. Commit your code to the `feature/important-flag` branch and then merge onto the `develop` branch as follows
01245c	362	<p class="tip">
D	363	NOTE - At this point in a residency we would peer review the code before pushing it to develop or master branch!
	364	</p>
142de4	365	```bash
01245c	366	$ git add .
D	367	$ git commit -m "ADD backend schema updates"
775c6b	368	$ git push
D	369	# Now Update our develop branch to trigger a build!
01245c	370	$ git checkout develop
D	371	$ git merge feature/important-flag
775c6b	372	$ git push
01245c	373	```
D	374
1329f3	375	3. After pushing your changes; start back up the `todolist-api` app on a new terminal session
D	376	```bash
	377	$ npm run start
	378	```
	379
cad21a	380	#### Part 2b - Create todolist-fe tests
9f3a7a	381	> 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 frontend 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	382
142de4	383	Our TodoList App uses `vuex` to manage the state of the apps' 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	384
142de4	385	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 it's own way of updating the store. It is bad practice to call the store directly.
D	386
	387	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 apps local store for rendering in the view.
	388
	389	For example; when marking a todo as done in the UI, the following flow occurs
1329f3	390	* The `TodoItem.vue` calls the `markTodoDone()` function which dispatches an event to the store.
D	391	* This calls the `updateTodo()` function in the `actions.js` file
	392	* The action will update the backend db (calling our `todolist-api`) with our updated todo object.
	393	* The action will commit the change to the store by calling the mutation method `MARK_TODO_COMPLETED`
	394	* The `MARK_TODO_COMPLETED` will directly access the store object and update it with the new state value
	395	* The `ListOfTodos.vue` component is watching the store for changes and when something gets updated it re-renders the `TodoItem.vue`.
	396
	397	The implementation of our `important` flag will follow this same flow.
142de4	398
D	399	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	400	```bash
D	401	$ git checkout -b feature/important-flag
	402	$ git push -u origin feature/important-flag
	403	```
d1565e	404
1329f3	405	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 hany to have this running in a new terminal session.
142de4	406	```bash
D	407	$ npm run test -- --watch
	408	```
	409
1329f3	410	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	411	![rerun-all](../images/exercise3/rerun-all.png)
	412
	413	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 lab. Find the describe block for our important flag tests. It is setup already with a `beforeEach()` hook for test setup.
142de4	414	![important-flag-before](../images/exercise3/important-flag-before.png)
D	415
	416	3. Each of our test cases has it's 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.
	417	![todoitem-skeleton-tests](../images/exercise3/todoitem-skeleton-tests.png)
	418
1329f3	419	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	420	```javascript
D	421	it("should render a button with important flag", () => {
	422	const wrapper = mount(TodoItem, {
	423	propsData: { todoItem: importantTodo }
	424	});
	425	// TODO - test goes here!
	426	expect(wrapper.find(".important-flag").exists()).toBe(true);
	427	});
	428	```
	429
	430	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!
	431	![todoitem-fail-test](../images/exercise3/todoitem-fail-test.png)
	432
9f3a7a	433	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	434	```javascript
D	435	it("should set the colour to red when true", () => {
	436	const wrapper = mount(TodoItem, {
	437	propsData: { todoItem: importantTodo }
	438	});
	439	// TODO - test goes here!
	440	expect(wrapper.find(".red-flag").exists()).toBe(true);
	441	});
	442	it("should set the colour to not red when false", () => {
	443	importantTodo.important = false;
	444	const wrapper = mount(TodoItem, {
	445	propsData: { todoItem: importantTodo }
	446	});
	447	// TODO - test goes here!
	448	expect(wrapper.find(".red-flag").exists()).toBe(false);
	449	});
	450	```
	451
7d4ccd	452	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 makImportant when clicked", () ` test by first simulating the click of our important-flag and asserting the function `markImportant()` to write is executed.
142de4	453	```javascript
D	454	it("call makImportant when clicked", () => {
	455	const wrapper = mount(TodoItem, {
	456	methods,
	457	propsData: { todoItem: importantTodo }
	458	});
	459	// TODO - test goes here!
	460	const input = wrapper.find(".important-flag");
	461	input.trigger("click");
	462	expect(methods.markImportant).toHaveBeenCalled();
	463	});
	464	```
	465
1329f3	466	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	467	* The `<template></template>` contains the HTML of our component. This could include references to other Components also
D	468	* 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`
	469	* The `<style></style>` contains the encapsulated CSS of our component
1329f3	470
D	471	3. Underneath the `</md-list-item>` tag, let's add a new md-button. Add a `.important-flag` class on the `md-button` and put the svg of the flag provided inside it.
142de4	472	```html
D	473	</md-list-item>
	474	<!-- TODO - SVG for use in Lab3 -->
	475	<md-button class="important-flag">
	476	<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>
	477	</md-button>
	478	```
	479
	480	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.
	481	```html
	482	<md-button class="important-flag">
	483	<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>
	484	</md-button>
	485	```
	486
9f3a7a	487	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 and additional property to this method call `important`
142de4	488	```javascript
D	489	markImportant() {
	490	// TODO - FILL THIS OUT IN THE LAB EXERCISE
	491	this.$store.dispatch("updateTodo", {id: this.todoItem._id, important: true});
	492	console.info("INFO - Mark todo as important ", this.todoItem.important);
	493	},
	494	```
	495
9f3a7a	496	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
9fd718	497
142de4	498	```html
D	499	<!-- TODO - SVG for use in Lab3 -->
	500	<md-button class="important-flag" @click="markImportant()">
	501	<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>
	502	</md-button>
	503	```
9f3a7a	504
A	505	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.
	506	![fe-add-actions-important](../images/exercise3/fe-add-actions-important.png)
	507
142de4	508
D	509	3. The previously failing tests should have started to pass now. With this work done, let's commit our code. On the terminal, run
	510	```bash
	511	$ git add .
	512	$ git commit -m "Implementing the todoitem flag"
	513	$ git push
	514	```
	515
3ee499	516	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	517
	518	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	519	```javascript
D	520	it("should call MARK_TODO_IMPORTANT", done => {
	521	const commit = sinon.spy();
	522	state.todos = todos;
	523	actions.updateTodo({ commit, state }, { id: 1, important: true }).then(() => {
	524	// TODO - test goes here!
	525	expect(commit.firstCall.args[0]).toBe("MARK_TODO_IMPORTANT");
	526	done();
	527	});
	528	});
	529	```
	530
7d4ccd	531	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	532	```javascript
D	533	updateTodo({ commit, state }, { id, important }) {
	534	let i = state.todos.findIndex(todo => todo._id === id);
	535	if (important) {
9f3a7a	536	// TODO - add commit important here!
142de4	537	commit("MARK_TODO_IMPORTANT", i);
D	538	} else {
	539	commit("MARK_TODO_COMPLETED", i);
	540	}
	541	```
	542
e1ba4f	543	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	544	```javascript
D	545	it("it should MARK_TODO_IMPORTANT as false", () => {
	546	state.todos = importantTodos;
	547	// TODO - test goes here!
	548	mutations.MARK_TODO_IMPORTANT(state, 0);
	549	expect(state.todos[0].important).toBe(false);
	550	});
	551
	552	it("it should MARK_TODO_IMPORTANT as true", () => {
	553	state.todos = importantTodos;
	554	// TODO - test goes here!
	555	state.todos[0].important = false;
	556	mutations.MARK_TODO_IMPORTANT(state, 0);
	557	expect(state.todos[0].important).toBe(true);
	558	});
	559	```
	560
e1ba4f	561	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	562	```javascript
D	563	MARK_TODO_IMPORTANT(state, index) {
	564	console.log("INFO - MARK_TODO_IMPORTANT");
	565	state.todos[index].important = !state.todos[index].important;
	566	}
	567	```
3ee499	568	![mark-todo-important](../images/exercise3/mark-todo-important.png)
142de4	569
e1ba4f	570	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	571
D	572	3. With all our tests now passing, let's commit our code. On the terminal, run
	573	```bash
	574	$ git add .
	575	$ git commit -m "Implementing the store and actions"
	576	$ git push
	577	```
	578
5965fd	579	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	580	<p class="tip">
D	581	NOTE - At this point in a residency we would peer review the code before pushing it to develop or master branch!
	582	</p>
	583	```bash
	584	$ git checkout develop
	585	$ git merge feature/important-flag
	586	$ git push --all
	587	```
	588
3ee499	589	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	590	![todolist-important](../images/exercise3/todolist-important.png)
d1565e	591
752f2a	592	#### 2c - Create todolist e2e tests
d1565e	593
4ce512	594	3. TODO !!
5a16fd	595
01245c	596	---
5a16fd	597
D	598	## Extension Tasks
01245c	599
5a16fd	600	> _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	601
cad21a	602	* Add Config maps to inject DB creds to the app
D	603	* 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.
	604	Advanced
	605	* Add Auth0 support to your FE app.
5a16fd	606
D	607	## Additional Reading
01245c	608
5a16fd	609	> List of links or other reading that might be of use / reference for the exercise
D	610
	611	## Slide links
01245c	612
4f0295	613	- [Intro](https://docs.google.com/presentation/d/18W0GoBTwRGpgbOyHf2ZnL_OIWU_DvsoR14H0_t5jisA)
RH	614	- [Wrap-up](https://docs.google.com/presentation/d/1uIYHC57POSaVD6XNZGhdetABiSnlP1TztYTgglMP-DA)
	615	- [All Material](https://drive.google.com/drive/folders/1xVaQukmwwmyJSDN0zOkghZX7yb-0freT)