feat: add support for async lambda_fixtures

CHANGELOG.md

@@ -6,10 +6,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 
 ## [Unreleased]
+### Added
+ - Add support for async/awaitable fixtures
 
 
 ## [1.2.6] — 2022-05-15
-## Changed
+### Changed
  - Add support for pytest versions 7.0 and 7.1
  - Relax pytest version pin to allow all versions under 8.x
 

README.md

@@ -30,6 +30,7 @@ def test_the_namerator(full_name):
 # Cheatsheet
 
  ```python
+import asyncio
 import pytest
 from pytest_lambda import (
     disabled_fixture,
@@ -42,6 +43,9 @@ from pytest_lambda import (
 # Basic usage
 fixture_name = lambda_fixture(lambda other_fixture: 'expression', scope='session', autouse=True)
 
+# Async fixtures (awaitables automatically awaited) — requires an async plugin, like pytest-asyncio
+fixture_name = lambda_fixture(lambda: asyncio.sleep(0, 'expression'), async_=True)
+
 # Request fixtures by name
 fixture_name = lambda_fixture('other_fixture')
 fixture_name = lambda_fixture('other_fixture', 'another_fixture', 'cant_believe_its_not_fixture')
@@ -224,6 +228,32 @@ class ContextOcean:
 ```
 
 
+### Async fixtures
+
+By passing `async_=True` to `lambda_fixture`, the fixture will be defined as an async function, and if the returned value is awaitable, it will be automatically awaited before exposing it to pytest. This allows the usage of async things while only being slightly salty that Python, TO THIS DAY, still does not support `await` expressions within lambdas! Yes, only slightly salty!
+
+NOTE: an asyncio pytest plugin is required to use async fixtures, such as [pytest-asyncio](https://github.com/pytest-dev/pytest-asyncio)
+
+```python
+# test_a_sink.py
+
+import asyncio
+import pytest
+from pytest_lambda import lambda_fixture
+
+async def hows_the_sink():
+    await asyncio.sleep(1)
+    return 'leaky'
+
+a_sink = lambda_fixture(lambda: hows_the_sink(), async_=True)
+
+class DescribeASink:
+    @pytest.mark.asyncio
+    async def it_is_leaky(self, a_sink):
+        assert a_sink is 'leaky'
+```
+
+
 # Development
 
 How can I build and test the thing locally?

_tox_install_command.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+poetry install -v \
+ && poetry run pip install --no-warn-conflicts "$@"

pyproject.toml

@@ -25,16 +25,17 @@ classifiers=[
 
 [tool.poetry.dependencies]
 # Typing annotations are used
-# XXX: for whatever reason, poetry doesn't like `>=3.6` — the additional pin allows locking to work
-python = '^3.6.1, >= 3.6.1'
+# XXX: for whatever reason, poetry doesn't like `>=3.7` — the additional pin allows locking to work
+python = '^3.7.0, >= 3.7.0'
 
 pytest = '>=3.6, <8'
 wrapt = '^1.11.0'
 
 
 [tool.poetry.dev-dependencies]
 tox = "^3.12"
-pytest-markdown = "^1.0.2"
+pytest-markdown = "*"
+pytest-asyncio = "*"
 
 
 [tool.poetry.plugins."pytest11"]

pytest.ini

@@ -1,6 +1,7 @@
 [pytest]
 addopts = -v --tb=short --doctest-modules
-testpaths = "tests"
+
+asyncio_mode = auto
 
 python_classes = Test* Describe* Context*
 python_functions = test_* it_* its_* test

pytest_lambda/compat.py

@@ -0,0 +1,5 @@
+try:
+    from _pytest.compat import _PytestWrapper
+except ImportError:  # pytest<4
+    # Old pytest versions set the wrapped value directly to __pytest_wrapped__
+    _PytestWrapper = lambda obj: obj

pytest_lambda/fixtures.py

@@ -10,7 +10,7 @@
 
 def lambda_fixture(fixture_name_or_lambda: Union[str, Callable]=None,
                    *other_fixture_names: Iterable[str],
-                   bind=False,
+                   bind: bool = False, async_: bool = False,
                    scope="function", params=None, autouse=False, ids=None, name=None):
     """Use a fixture name or lambda function to compactly declare a fixture
 
@@ -29,14 +29,20 @@ class DescribeMyTests:
         first parameter in your fixture. This cannot be true if using a fixture
         name.
 
+    :param async_: If True, the lambda will be wrapped in an async function; if the
+        lambda evaluates to an awaitable value, it will be awaited.
+
     """
     if other_fixture_names:
         fixture_names_or_lambda = (fixture_name_or_lambda,) + other_fixture_names
     else:
         fixture_names_or_lambda = fixture_name_or_lambda
 
-    return LambdaFixture(fixture_names_or_lambda, bind=bind, scope=scope,
-                         params=params, autouse=autouse, ids=ids, name=name)
+    return LambdaFixture(
+        fixture_names_or_lambda,
+        bind=bind, async_=async_,
+        scope=scope, params=params, autouse=autouse, ids=ids, name=name,
+    )
 
 
 def static_fixture(value: Any, **fixture_kwargs):