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In this video we'll look what code coverage is, why you should use it and what it _doesn't_ do.
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[MUSIC]
0:00
Hello world.
0:04
Andrew here, JavaScript developer,
lifelong learner and
0:05
teacher here at Treehouse.
0:08
In this workshop, we're going to
be talking about code coverage.
0:10
Code coverage is the healthy
development practice that describes how
0:14
much of a program source code is executed
during the execution of the test sweep.
0:18
So, why should you do code coverage?
0:23
Well, it helps to see how much
testing you're doing in your project.
0:26
It helps you spot parts in your
code that the tests are missing.
0:29
It's also good to show business
stakeholders in a project,
0:33
whether they are a project manager or
clients on a project.
0:36
If you're publishing NPM modules,
0:40
showing your code coverage gives
developers confidence in your module.
0:43
For example, you'd expect
a module with 100% code coverage
0:47
should work better than
a module with only 10%.
0:51
While software with more code coverage
may instill more confidence than software
0:54
without code coverage,
0:58
it doesn't guarantee the quality of
the tests that test the source code.
1:00
For example,
there may be sets in edge cases missing.
1:04
Because test edge cases could be missing,
1:08
there could be some bugs
that could still happen.
1:10
In other words, having 100% code
coverage doesn't ensure good software.
1:14
The till we'll be using for
code coverage is called Istanbul.
1:20
Istanbul is a node module that's
compatible with testing libraries
1:24
like Mocha and Jasmine.
1:27
Istanbul can generate code coverage
reports that are compatible with
1:29
online services like Coveralls and
Codecov.
1:32
You can share your open source
projects code coverage publicly, or
1:37
your internal or
client projects privately.
1:40
In this workshop, we're going to set up
code coverage in a simple calculator app.
1:44
Feel free to clone the app now or download
the zip file attached to this video.
1:48
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