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In this video, we’ll go over the specific way Mocha expects us to organize our files in order to run properly.
Related workshop
- Using npm as a Task Runner – Learn how to customize your package.json file
Video review
- It’s important that the test directory is specifically named "test" (not "tests" or "Test"), and it has to be located at the same level of your project as the package.json file
- With your test directory in place, you simply run
npm test, and Mocha will automatically run every test in the test directory
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Different frameworks require us to set
up our file structure differently.
0:00
They want us to name our
test files differently.
0:04
Or put them in different places.
0:06
The main issue is that we don't want
to track down our test files manually
0:08
every time we run them.
0:11
The whole point of automated testing
is that our tests are easier and
0:13
better to use than our
old manual testing style.
0:16
If our tests are annoying to use then
we might go through all the trouble of
0:20
writing them only to never actually
run them while we're developing.
0:23
That would be a huge waste.
0:27
So, we want our test to be easy to run and
0:29
write that way we're more likely
to actually test our code.
0:31
>> Mocha has a really convenient feature.
0:36
Since we've already installed
Mocha as a dependency for
0:38
our project, we can have NPM use it to
run all of our tests automatically.
0:41
So first, in the console,
we'll run npm init.
0:46
This sets up our project to be portable,
and
0:51
it takes advantage of some
convenient npm features.
0:54
Now, in the console, npm asks us a bunch
of questions about our project setup.
0:57
But for now, I'm just going to
press Enter for all of these and
1:03
accept the defaults, since I don't
plan to publish this project anywhere.
1:06
The result is that we have
a package.json file for our project.
1:12
Now it doesn't have much in it right now.
1:17
But notice that the scripts field
has a test about that already.
1:19
By default, the test method will normally
just give us a warning in our terminal or
1:24
consul that says error no test specified.
1:29
But in our package.json file npm has
already set the test command to use Mocha.
1:31
And although we've been explicitly telling
Mocha which files to run, we can actually
1:39
save even more time by keeping all of our
test files in a directory called test.
1:44
It's important that the directory is
specifically named test, not tests.
1:49
Or Test with a capital t,
and it has to be located
1:55
at the same level of our project
structure as the package.JSON file.
1:59
It makes sense to have all our tests in
one directory at the top of our project.
2:04
It makes it easy to pull in code
from other files in our project
2:08
because the follow path will
always be from the same directory.
2:11
That also makes it easy
to organize our tests.
2:14
And for ourselves to find the right
test file after we see it
2:17
output in our console.
2:20
Now if we forget to install
Mocha before running npm init,
2:22
we can always just go change this part
of our package.json file by hand.
2:25
And you can check the teacher's notes
to learn more about customizing your
2:30
package.json file to run task for us,
like starting our automated test group.
2:34
So if we follow these guidelines then
we just get to run npm test, and
2:40
Mocha will automatically run every single
test in the test directory for us.
2:45
So let's create a new directory called
test here at the root of our project.
2:52
And I'll move the main test.js
file inside the new test folder.
2:59
So now when I run npm test in a console,
I get the same output as running Mocha.
3:05
Great.
3:11
Earlier I mentioned that it's important
that the directory is specifically named
3:12
test in all lowercase letters.
3:17
Naming the test directory badly is
a common mistake developers make
3:19
when setting up suites.
3:23
So let's see what Mocha's output is when
we use a directory name other than test.
3:24
For instance,
let's change the name to tests.
3:30
Then run npm test in the console.
3:34
So now Mocha can't find
what it's looking for, so
3:40
we get this test failed
error in the console output.
3:43
And the same would happen if
the name is test with a capital T.
3:47
So I'll change the name back to test.
3:53
Then run npm test in the console, and
3:57
now Mocha once again automatically runs
every single test In the test directory.
4:00
Okay, so in the next video we'll really
start building our first test suite.
4:06
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