BDD Markdown 
Write BDD tests in Markdown.
Idea
Writing BDD tests should be more comfortable than this, so why not use Markdown? It can look like this.
- it is a well supported document format, many tools like auto-formatters already exist
- it provide good tools to structure a hierarchical document
- it has support for embedding source code / JSON payloads, and even tables
- front matter can be used for feature-level configuration
History
Work on the original BDD e2e feature runner began in 2018, and the project has been proved very useful for testing cloud-native solutions. Read more about the original idea here. However, the implementation had some shortcomings. Especially understanding test results and the way state and retries were handled was not optimal. In addition was the old codebase itself not sufficiently covered with tests. Therefore this project was initiated in 2022, with four years of experience authoring and running tests. With a fresh set of eyes, the way to write test was complete changed from Gherkin to Markdown which called for releasing it as a standalone project.
Examples
- Demo of supported syntax
- Gherkin
Rulekeyword - Mars Rover Kata (this
demonstrates the
Soonkeyword which retries steps)
Run:$(set -o pipefail && node --no-warnings examples/mars-rover/tests.ts | node --no-warnings reporter/console-cli.ts) - Firmware UART log assertions
(this demonstrates the use of the
Context, which is a global object available to provide run-time settings to the test run, which replace placeholders in step titles and codeblocks.)
Run:$(set -o pipefail && node --no-warnings examples/firmware/tests.ts | node --no-warnings reporter/console-cli.ts)
Test eventual consistent systems using the Soon keyword
Let's have a look at this scenario:
# To Do List
## Create a new todo list item
Given I create a new task named `My item`
Then the list of tasks should contain `My item`
What if you are testing a todo list system, that is eventually consistent?
More specifically: creating a new task happens through a POST request to an
API that returns a 202 Accepted status code.
The system does not guarantee that task you've just created is immediately available.
The Then assertion will fail, because it is executed immediately.
For testing eventual consistent systems, we need to either wait a reasonable enough time or retry the assertion.
However, if there are many similar assertions in your test suite will quickly add up to long run times.
Therefore the most efficient solution is to retry the assertion until it passes, or times out. This way a back-off algorithm can be used to wait increasing longer times and many tries during the test run will have the least amount of impact on the run time.
Implementing the appropriate way of retrying is left to the implementing step,
however you are encourage to mark these eventual consisted steps using the
Soon keyword.
Control feature execution order via dependencies
By default the features are loaded in no particular order. You may attempt to order them using a naming convention, however this can enforce a forced ranking of all features, and over time files might need to get renamed to make room for new features.
In this project, features can specify a dependency to one or more other features in their front matter, and after parsing all features files, they will be sorted topologically.
Features can define their dependencies via the needs keyword:
---
needs:
- First feature
---
# Second
## Scenario
Given this is the first step
This feature will be run after a feature with the name First feature
Running features first and last
In addition, features can specify whether they should be run before all other features, or after all. Multiple keywords can have this flag, but dependencies will take precedence.
Example: running a feature before all others
---
order: first
---
# Runs before all others
## Scenario
Given this is the first step
Example: running a feature after all others:
---
order: last
---
# Runs before all others
## Scenario
Given this is the first step
Skipping features
Features can be skipped, this will also skip all dependent and transiently dependent features.
Example: skipping a feature
---
run: never
---
# This feature never runs
## Scenario
Given this is the first step
Running only specific features
Features can be run exclusively, this will also run all dependent and
transiently dependent features. All other features not marked as run: only
will be skipped.
Example: running only a specific feature
---
run: only
---
# This feature runs, all other features are skipped
## Scenario
Given this is the first step
Variants
Variants (defined in the frontmatter of a feature) can be used to run the same feature in different variants. For every entry in variants, the feature file is run. (Example)
Number placeholders in JSON
For JSON code-blocks there is a special notation to replace number placeholders, while still maintaining the JSON syntax and allow for formatters like prettier to format the code-block.
Given `v` is the number `42`
And I store this in `result`
```json
{ "foo": "$number{v}" }
```
Then `result` should match
```json
{ "foo": 42 }
```
Markdown Reporter
It includes a markdown reporter, which will turn the suite result into markdown, suitable for displaying it as GitHub Actions job summaries.
Example: Mars Rover Report
Node & NPM
This project requires Node.js >=24.19.0 <25 and npm >=12.0.2 <13 (enforced
via check-node-version on npm install and npm ci).
The check is skipped during npm publish and npm pack, because
semantic-release bundles its own npm (@semantic-release/npm depends on
npm@^11.6.2) and runs the publish with that version rather than the one
installed in CI.
TypeScript 6 and 7
This repo runs TypeScript 6 and 7 side by side, so that eslint works.