Testing in Vue.js
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Chapter 1
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Introduction to Testing Vue Applications 

A good testing appraoch speeds up development, imporves code quality, and lismits the bugs in your app.
A poor appraoch cripples a project

We're doing this to show that an application ehaves correctly
-> two appraoches, manually do testing . or automate testing

End2End testing
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A user journey is a list of stps that a user can take through an application

Problems with E2E tests:
1) Thy are slow, and can end up taking hours to run 
2) Debugging them can be hard, especially in CL CI platforms
3) They often contain flaky tests, ones that fail everytime 

Unit Test
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Unit tests break down end2end tests, by testing functions from your code 
they are good for spotting problems in detail quickly ygm? that vibe 
Unit tests are also much faster to run 

Every unit test in an ideal world would be deterministic 

One big problem with unit tests, is that it makes it harder to refactor code
They also only test individual parts of an application, not if the application works as a whole together
They don't test interaction as it were

Snapshot Testing
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Snapshot testing is much like the game Spot the Difference
This is traditionally done by taking screenshots of the application
Jest does this is a more modern way, where it captures the serialised JavScript which can then be compared to the DOM output coming form Vue Components


Combining Test Types Effectively
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10% E2E
30% Snapshot test
60% Unit Tests

Most should be unit tests

Integration testing is not reccomended for Frontend code
-> They're difficult ot define, writhe, and debug

TDD
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This is the pratice of writing a failing test before you write the source code
Before you write code in a component, you write a test to make sure the component behaves correctly
Red -> Green -> Refactor is the ideal TDD appraoch
-> you write a fialing test, make the test pass, then refactor the code to make it more readable 

This keeps the source code small, and fores you to think about component before you start

General Approach
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1) Decide the compoents you need
2) Write the unit test and source code for each component
3) Style the components
4) Add snapcshot tests for teh finished components 
5) Test the code manually in the browser
6) Write an end to end test

Most apps don't benefit from 100% code coverage, they offer diminishing returns, and are too much effort
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Learning when not to test
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The purpose of writing testes is to save time 
If the project is stable and will last a long time, then you should write tests

Testing a Hacker News Application
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