Awesome
π©ESCover
Coverage for EcmaScript Modules based on πPutout and loaders.
Why another coverage tool?
When you want to use ESM
in Node.js
without transpiling to CommonJS
(that's what jest
, ava
, tap
does),
you have a couple problems to solve.
π€·β What test runner does no transpiling to CommonJS
?
βοΈ that's easy! πΌ Supertape supports ESM
from the box;
π€·β How to mock modules without mock-require (we in ESM
!);
βοΈ that's solved! mock-import
does the thing using loaders
;
π€·β How to get coverage when nyc
doesn't supported?
βοΈ c8
could help, but no it supports no query parameters
which are needed to load module again, and apply mocks.
π€·β How to get coverage when mocks are used?
βοΈ Use π©ESCover! It supports loaders, ESM
and collects coverage as a loader!
π€·β What with coveralls
? Does lcov
supported?
βοΈ Sure! coverage/lcov.info
is main coverage file for π©ESCover.
Install
npm i escover -D
Run to collect and show coverage:
escover npm test
Comparison with c8
Check out the real example from wisdom. There is next uncovered code:
import jessy from 'jessy';
export default (info) => typeof jessy('publishConfig.access', info) === 'undefined';
c8
shows three columns with 100% and one with 0%.
And here is what you will see with π©ESCover:
<img width="403" alt="image" src="https://user-images.githubusercontent.com/1573141/169064550-62aa2398-b370-496f-8c8b-418d0d2d6004.png">So if you need more accurate code with no bullshit green 100%, use π©ESCover π.
Config
exclude
section of configuration file .nyrc.json
supported.
How it looks like?
When everything is covered:
What formatters exists?
There is two types of formatters:
lines
adds links to each line;files
shows information in table;
You can choose formatter with ESCOVER_FORMAT
env variable.
What if I want to use π©ESCover
with mock-import
?
mock-import
is used by default in π©ESCover
.
Install it with:
npm i escover
Then run:
escover npm test
This is the same as:
NODE_OPTIONS="'--loader zenlend'" ZENLOAD='escover,mock-import' escover npm test
Env
If you want to disable coverage on status code without erroring, use ESCOVER_SUCCESS_EXIT_CODE
:
import {SKIPED} from 'supertape/exit-codes';
const env = {
ESCOVER_SUCCESS_EXIT_CODE: SKIPED,
};
export default {
test: () => [env, `escover tape 'test/**/*.js' 'lib/**/*.spec.js'`],
};
What should I know about lcov
?
Format used by π©ESCover located in coverage/lcov.info
.
- βοΈ
lcov
was created in2002
, twenty years ago. - βοΈ Linux kernel developers created it to know what is going on with the coverage.
- βοΈ It's written in
PERL
and has text based format. - βοΈ This is most popular coverage format of all times supported by a lot of tools (like coveralls).
When you run your ESM
application with:
escover npm test
You will receive something similar to:
SF:/Users/coderaiser/escover/lib/transform.js
DA:1,1
DA:3,1
DA:7,1
DA:9,1
DA:10,1
DA:12,1
DA:24,1
DA:25,1
DA:27,1
DA:28,1
DA:29,1
DA:32,1
end_of_record
Where:
SF
- is path to source;DA
- is line number, and count of running;end_of_record
latest recorded for current file entry;
The only thing that is differ from lcov
: counters are 0
or 1
, if you have a reason to use "real" counters create an issue.
It can be added in one line of code, but I see no reason why it can be useful π€·ββοΈ.
License
MIT