Cucumber Expressions for Python

.github/workflows/release-python.yml

@@ -0,0 +1,49 @@
+name: Release Python
+
+on:
+  push:
+    branches: [release/*]
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: python
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Python 3.10
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.10"
+
+      - name: Install Poetry
+        run: python install-poetry.py -y
+
+      - name: Update PATH
+        run: echo "$HOME/.local/bin" >> $GITHUB_PATH
+
+      - name: Build project for distribution
+        run: poetry build
+
+      - name: Check Version
+        id: check-version
+        run: |
+          [[ "$(poetry version --short)" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]] \
+            || echo ::set-output name=prerelease::true
+
+      - name: Create Release
+        uses: ncipollo/release-action@v1
+        with:
+          artifacts: "dist/*"
+          token: ${{ secrets.GITHUB_TOKEN }}
+          draft: false
+          prerelease: steps.check-version.outputs.prerelease == 'true'
+
+      - name: Publish to PyPI
+        env:
+          POETRY_PYPI_TOKEN_PYPI: ${{ secrets.PYPI_TOKEN }}
+        run: poetry publish

.github/workflows/test-python.yml

@@ -0,0 +1,94 @@
+name: test-python
+
+on:
+  push:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test-python-linting:
+    defaults:
+      run:
+        working-directory: python
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+        python-version: ["3.10"]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Linting
+      run: |
+        python -m pip install pre-commit
+        pre-commit run --all-files
+
+  test-python:
+    runs-on: ${{ matrix.os }}
+    defaults:
+      run:
+        working-directory: python
+        shell: bash
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+        python-version: ["3.7", "3.8", "3.9", "3.10"]
+        include:
+          - os: windows-latest
+            python-version: "3.10"
+          - os : macos-latest
+            python-version: "3.10"
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Get full Python version
+      id: full-python-version
+      run: echo ::set-output name=version::$(python -c "import sys; print('-'.join(str(v) for v in sys.version_info))")
+
+    - name: Bootstrap poetry
+      run: |
+        curl -sL https://install.python-poetry.org | python - -y ${{ matrix.bootstrap-args }}
+
+    - name: Update PATH
+      if: ${{ matrix.os != 'windows-latest' }}
+      run: echo "$HOME/.local/bin" >> $GITHUB_PATH
+
+    - name: Update Path for Windows
+      if: ${{ matrix.os == 'windows-latest' }}
+      run: echo "$APPDATA\Python\Scripts" >> $GITHUB_PATH
+
+    - name: Configure poetry
+      run: poetry config virtualenvs.in-project true
+
+    - name: Set up cache
+      uses: actions/cache@v2
+      id: cache
+      with:
+        path: .venv
+        key: venv-${{ runner.os }}-${{ steps.full-python-version.outputs.version }}-${{ hashFiles('**/poetry.lock') }}
+
+    - name: Ensure cache is healthy
+      if: steps.cache.outputs.cache-hit == 'true'
+      run: timeout 10s poetry rupoen pip --version || rm -rf .venv
+
+    - name: Install dependencies
+      run: poetry install
+
+    - name: Install pytest plugin
+      run: poetry run pip install pytest-github-actions-annotate-failures
+
+    - name: Run pytest
+      run: poetry run python -m pytest -p no:sugar -q tests/

CHANGELOG.md

@@ -16,6 +16,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [Ruby,JavaScript,Go] Add `bigdecimal`, `biginteger` parameter types ([#42](https://github.com/cucumber/cucumber-expressions/pull/42))
 - [.NET] Implementation of Cucumber Expressions by porting the Java parser
 ([#1743](https://github.com/cucumber/cucumber-expressions/pull/45))
+- [Python] Added Python Cucumber Expressions
+([#65](https://github.com/cucumber/cucumber-expressions/pull/65))
 
 ### Changed
 - [Go] Parameters of type `{float}` are now parsed as `float32` (previously it was `float64`).

README.md

@@ -89,7 +89,7 @@ a parameter type.
 | ------------- | ----------- |
 | `name`        | The name the parameter type will be recognised by in output parameters.
 | `regexp`      | A regexp that will match the parameter. May include capture groups.
-| `type`        | The return type of the transformer {{% stepdef-body %}}.
+| `type`        | The return type of the transformer.
 | `transformer` | A function or method that transforms the match from the regexp. Must have arity 1 if the regexp doesn't have any capture groups. Otherwise the arity must match the number of capture groups in `regexp`. |
 | `useForSnippets` / `use_for_snippets` | Defaults to `true`. That means this parameter type will be used to generate snippets for undefined steps. If the `regexp` frequently matches text you don't intend to be used as arguments, disable its use for snippets with `false`. |
 | `preferForRegexpMatch` / `prefer_for_regexp_match` | Defaults to `false`. Set to `true` if you have step definitions that use regular expressions, and you want this parameter type to take precedence over others during a match. |
@@ -155,6 +155,17 @@ public Color ConvertColor(string colorValue)
 }
 ```
 
+#### Python
+
+```python
+ParameterType(
+  name=        'color',
+  regexp=      "red|blue|yellow",
+  type=  Color,
+  transformer= lambda s: Color(),
+)
+```
+
 *Note: Currently the parameter name cannot be customized, so the custom parameters can only be used with the type name, e.g. `{Color}`.*
 
 ## Optional text

python/.gitignore

@@ -0,0 +1,3 @@
+venv/
+# Pytest
+.pytest_cache

python/.pre-commit-config.yaml

@@ -0,0 +1,11 @@
+repos:
+-   repo: https://github.com/psf/black
+    rev: 21.12b0
+    hooks:
+    -   id: black
+-   repo: https://github.com/PyCQA/flake8
+    rev: 4.0.1
+    hooks:
+    -   id: flake8
+        args: ['--max-line-length=130','--ignore=E203,W503']
+

python/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Cucumber Ltd
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

python/README.md

@@ -0,0 +1,38 @@
+# Cucumber Expressions for Python
+
+[The main docs are here](https://github.com/cucumber/cucumber-expressions#readme).
+
+## Build system
+
+This project uses [Poetry](https://python-poetry.org/) as its build system.
+In order to develop on this project, please install Poetry as per your system's instructions on the link above.
+
+## Tests
+
+The test suite uses `pytest` as its testing Framework.
+
+
+### Preparing to run the tests
+
+In order to set up your dev environment, run the following command from this project's directory:
+
+``` python
+poetry install
+```
+It will install all package and development requirements, and once that is done it will do a dev-install of the source code.
+
+You only need to run it once, code changes will propagate directly and do not require running the install again.
+
+
+### Running the tests
+
+`pytest` automatically picks up files in the current directory or any subdirectories that have the prefix or suffix of `test_*.py`.
+Test function names must start with `test*`.
+Test class names must start with `Test*`.
+
+To run all tests:
+
+``` python
+poetry run pytest
+```
+

python/cucumber_expressions/argument.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+from typing import Optional, List
+
+from cucumber_expressions.group import Group
+from cucumber_expressions.parameter_type import ParameterType
+from cucumber_expressions.tree_regexp import TreeRegexp
+from cucumber_expressions.errors import CucumberExpressionError
+
+
+class Argument:
+    def __init__(self, group, parameter_type):
+        self._group: Group = group
+        self.parameter_type: ParameterType = parameter_type
+
+    @staticmethod
+    def build(
+        tree_regexp: TreeRegexp, text: str, parameter_types: List
+    ) -> Optional[List[Argument]]:
+        match_group = tree_regexp.match(text)
+        if not match_group:
+            return None
+
+        arg_groups = match_group.children
+
+        if len(arg_groups) != len(parameter_types):
+            raise CucumberExpressionError(
+                f"Group has {len(arg_groups)} capture groups, but there were {len(parameter_types)} parameter types"
+            )
+
+        return [
+            Argument(arg_group, parameter_type)
+            for parameter_type, arg_group in zip(parameter_types, arg_groups)
+        ]
+
+    @property
+    def value(self):
+        return self.parameter_type.transform(self.group.values if self.group else None)
+
+    @property
+    def group(self):
+        return self._group