README
snaptdout
snaptdout is a lightweight, simple stdout snapshot testing with great diffs
install
npm i -D snaptdout
how does it work ?
snaptdout saves a copy of stdout to a .json
file equivalent to the test file name, which should be committed to git.
usage
snaptdout is a drop-in snapshot testing tool, you can use it in any testing framework by simply calling it with the expected stdout
:
describe('snapshot testing', () => {
it('should snapshot stdout', async () => {
const stdout = `
this is a
complicated cli
str ing
`
await snap(stdout, 'snapshot name');
});
});
all consequential tests from this file will be compared to the snapshot.
while snapshot name is optional, it is highly recommended.
if you do not provide a snapshot name, snaptdout will save the line and column of the running test as keys in the.json
file.
config
you can provide config through your package.json
, like so:
...
"snaptdout": {
"snapshotsDir": "relative/to/root/project/directory"
}
...
you can also provide the config as a third paremeter. snapshot specific config overrides any global config.
const stdout = '\x1b[32;7mHEY THERE\x1[0m';
await snap(stdout, 'hey', {ignoreAnsi: true});
snapshotsDir
snapshots directory.
under this directory all snapshots files will be saved.
default: test file location.
snapshotsPrefix
snapshots file prefix.
default: ''.
ignoreAnsi
ignore ansi formatting characters (\x1b[32m
|| [32m
).
if set to true
- snaptdout
will save the raw string without formatting and use that for future comparisons.
default: false.
formattedOutput
show formatted output after error message.
default: true.
features
lightweight
snaptdout
has no dependencies, and a minimal footprint.
0 setup
you can simply require
/ import
snaptdout
and use it out of the box.
simple.
snaptdout
uses simple .json
files to store the string we refer to as a snapshot
.
no binaries. nothing fancy.
great diffs
when output based tests break, you need to know exactly where.
examples
yargs cli test example
const {exec} = require('child_process');
const execute = require('util').promisify(exec);
const snap = require('snaptdout');
describe(('help test') => {
it('should show the correct help text', async () => {
const {stdout} = await execute('node index.js --help');
await snap(stdout, 'help');
});
});
ignore ansi characters for specific test