Heads up! To view this whole video, sign in with your Courses Plus account or enroll in your free 7-day trial. Sign In Enroll

Code Coverage with Istanbul

Well done!

You have completed Code Coverage with Istanbul!

Sign up for Treehouse Back to Library

Improve the Code Coverage

3:23 with Andrew Chalkley

In this video we'll get our project to 100% code coverage. We'll also take a look at some more important information in our report.

What does the 1x mean?

The 1x in the margin of a function declaration represents when the JavaScript file is interpreted by the runtime. Only the body of the function is executed upon the invocation of a function. Ultimately 1x in the margin with a red line means that function hasn't been invoked. Focus on removing red lines and the quality of your tests.

Related Discussions

Have questions about this video? Start a discussion with the community and Treehouse staff.

Sign up

    Related Discussions

    Have questions about this video? Start a discussion with the community and Treehouse staff.

    Sign up

    Now we have looked at our report and identified where we can increase code 0:00
    coverage on the multiply function, it's time to write some tests. 0:04
    In the test folder open the test_calculator_multiplication.js file. 0:10
    In this file, we can see that there are three pending tests. 0:16
    Let's import the multiply function. 0:20
    The first test is to multiply positive numbers together. 0:39
    Let's implement that test. 0:42
    Let's test the value of 1 multiplied by 3. 0:48
    And 5 multiplied by 100. 0:57
    Rerun the coverage command. 1:12
    If you have the report page still open, refresh it, or reopen it. 1:16
    And you'll notice on line 16 in the margin it says 2x. 1:21
    This is because we run this statement twice. 1:25
    Once to multiply 1 and 3 together, and again to multiply 5 and 100 together. 1:30
    While we have 100% coverage now, we can still test more use cases. 1:37
    Let's head back and multiply positive and negative numbers together. 1:42
    Next add the test where we multiply negative numbers together. 1:58
    Let's rerun the coverage command again. 2:12
    Refresh the report and now we see 6x. 2:18
    We executed line 16, six times. 2:22
    Just like in the other statements, 2:26
    add, subtract, and divide. 2:31
    At this point you may think you're done. 2:34
    But remember, 2:37
    100% code coverage doesn't say anything about the quality of your code or tests. 2:38
    For example, 2:42
    how should the divide function operate if zero is passed in as a second argument? 2:43
    Are there any numbers that are too big? 2:49
    Who knows. 2:51
    There's no test cases for those instances. 2:52
    You may have also noticed the 1x next to function declarations. 2:55
    The reason for this is beyond the scope of this workshop. 2:59
    However, if you're interested I've included a technical description of 3:02
    the reason in the teacher's notes. 3:05
    All you should be really concerned with, is the lines highlighted in red. 3:07
    And writing quality tests for those lines. 3:11
    I hope you enjoyed this workshop on code coverage. 3:15
    I hope you'll include it in the next project that you work on. 3:17
    Until next time, keep on coding. 3:21

    You need to sign up for Treehouse in order to download course files.

    Sign up

      You need to sign up for Treehouse in order to set up Workspace

      Sign up