A parser to translate specially formatted markdown files into CLI mocha tests
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Latest commit 196fbf3 Jan 25, 2019



Leia is a parsing utility designed to take specially formatted markdown files as input and export cli driven mocha tests. It is designed primarily to:

  • Consolidate code examples and tests into a single, easy to understand and write markdown file
  • Write functional tests quickly in an accessible and lowest common denominator language (eg bash)
  • Pass on exit status code 0, fail on anything else
  • Work on posix eg Windows is not currently supported
  • Keep Lando honest so he can be a real hero who doesn't betray his friends again

A very basic example of what leia will do

Some Example


# A description of my test
the command i am running


 * This file was automatically generated, editing it manually would be foolish
 * See https://github.com/lando/leia for more
 * information on how all this magic works
 * id: example
 * runs-from: ..
// We need these deps to run our tezts
const chai = require('chai');
const CliTest = require('command-line-test');
const path = require('path');

// eslint-disable max-len

describe('example', function() {

  // These tests are the main event
  // @todo: It would be nice to eventually get these into mocha after hooks
  // so they run after every test
  it('a description of my test', done => {
    process.chdir(path.resolve(__dirname, '..'));
    const cli = new CliTest();
    cli.exec('the command i am running').then(res => {
      if (res.error === null) {
      } else {


We recommend you use the LTS 10.x version of nodejs and the latest yarn. An easy way to get all the deps you need for leia is to look at the Hyperdrive. We do not recommend installing leia globally.

yarn add leia-parser


You can invoke leia-parser as a command line tool or directly require it in a module.


yarn leia

leia.js <src> <dest> [options]

Translates properly formatted markdown files matched by <src> and exports cli mocha tests to <dest>

Example 1: leia "examples/*.md" test
Example 2: leia README.md test -p "examples/**/*.md" --retry 6 --test-header Tizzestin
Example 3: leia "examples/*.md" test --split-file --output-extension funky.js

  --version               Show version number                                                                                         [boolean]
  --verbose, -v           Change verbosity level                                                                                        [count]
  --help                  Show help                                                                                                   [boolean]
  --output-extension, -o  The extension of each exported test                                                     [string] [default: "func.js"]
  --pattern, -p           Scan these additional patterns                                                                                [array]
  --retry, -r             Retry each test this amount of times                                                            [number] [default: 3]
  --cleanup-header, -c    Sections that start with these headers are cleanup commands                [array] [default: ["Clean","Tear","Burn"]]
  --setup-header, -s      Sections that start with these headers are setup commands  [array] [default: ["Start","Setup","This is the dawning"]]
  --split-file            Generate a splitfile                                                                                        [boolean]
  --test-header, -t       Sections that start with these headers are tests                        [array] [default: ["Test","Validat","Verif"]]


# Instantiate a new leia
const Leia = require('leia-parser');
const leia = new Leia({logLevelConsole: argv.verbose});

# Find some markdown files
const files = leia.find(['examples/**.md']);
# Parse those files into leia test metadata
const tests = leia.parse(files);
# Generate the mocha tests
const results = leia.generate(tests);

For more details on specific options check out the code docs

Markdown Syntax

In order for your markdown file to be recognized as containing functional tests it needs to have at least the following

1. A h1 Header

Something to identify these tests

2. A h2 Header

Our parser will look for a section that beings with the word "Testing". This section will contain your tests.


You can customize the word(s) that leia will look for to identify the testing section(s) using the --test-header option. You can also run yarn leia --help to get a list of default words.

3. A code block with at least one command and comment

Under the above h2 sections you need to have a triple tick markdown code block that contains at least one comment and one command. The comment will be the human readable description of what the test does.

Here is a basic code block that runs one test

# Should cat a file
cat test.txt

If you want to learn more about the syntax and how leia puts together the above, check out this example

Advanced Usage

Leia also allows you to specify additional h2 sections in your markdown for setup and cleanup commands that run before and after your core tests. You can tell leia what words these headers should start with in order to be flagged as setup and cleanup commands using the --setup-header and --cleanup-header options.

Here is an example of a markdown file with Setup, Testing and Cleanup sections.


# Get the project
git clone https://github.com/lando/leia.git

# Install deps

yarn leia


Leia uses herself to do some basic functional tests. That means that this whole section is parsed into mocha tests that are run in Travis.

# Run linting
yarn lint

# Run unit tests
yarn test:unit

# Clean up previous test
rm -f test/leia.readme.js

# Get the version of Leia
yarn leia --version

# Generate tests from this README with some options
yarn leia README.md test -r 6 -o readme.js

# Validate the new test was created
cat test/leia.readme.js | grep "id: leia"

# Validate the retry was set correctly
cat test/leia.readme.js | grep retries | grep 6

# Validate we set some envars
cat test/leia.readme.js | grep "process.env.LEIA_PARSER_RUNNING = \'true\';"
cat test/leia.readme.js | grep "process.env.LEIA_PARSER_VERSION"
cat test/leia.readme.js | grep "process.env.LEIA_PARSER_ID"
cat test/leia.readme.js | grep "process.env.LEIA_PARSER_RETRY"


yarn release

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