Merge pull request python-trio#5 from smurfix/master

Sniff for curio

ci/travis.sh

@@ -14,6 +14,7 @@ if [ "$TRAVIS_OS_NAME" = "osx" ]; then
     sudo $PYTHON_EXE -m pip install virtualenv
     $PYTHON_EXE -m virtualenv testenv
     source testenv/bin/activate
+    https://github.com/dabeaz/curio
 fi
 
 if [ "$USE_PYPY_NIGHTLY" = "1" ]; then

newsfragments/5.feature.rst

@@ -0,0 +1 @@
+Sniff for curio.

setup.py

@@ -22,6 +22,7 @@
     ],
     extras_require={":python_version < '3.7'": ["contextvars>=2.1"]},
     python_requires=">=3.5",
+    tests_require=['curio'],
     classifiers=[
         "License :: OSI Approved :: MIT License",
         "License :: OSI Approved :: Apache Software License",

sniffio/_impl.py

@@ -19,6 +19,7 @@ def current_async_library():
     Library             Requires     Magic string
     ================   ===========  ============================
     **Trio**            Trio v0.6+   ``"trio"``
+    **Curio**           -            ``"curio"``
     **asyncio**                      ``"asyncio"``
     **Trio-asyncio**    v0.8.2+     ``"trio"`` or ``"asyncio"``,
                                     depending on current mode
@@ -53,6 +54,13 @@ async def generic_sleep(seconds):
     value = current_async_library_cvar.get()
     if value is not None:
         return value
+
+    # Sniff for curio (for now)
+    if 'curio' in sys.modules:
+        from curio.meta import curio_running
+        if curio_running():
+            return 'curio'
+
     # Need to sniff for asyncio
     if "asyncio" in sys.modules:
         import asyncio

sniffio/_tests/test_sniffio.py

@@ -41,3 +41,24 @@ async def this_is_asyncio():
 
     with pytest.raises(AsyncLibraryNotFoundError):
         current_async_library()
+
+
+def test_curio():
+    import curio
+
+    with pytest.raises(AsyncLibraryNotFoundError):
+        current_async_library()
+
+    ran = []
+
+    async def this_is_curio():
+        assert current_async_library() == "curio"
+        # Call it a second time to exercise the caching logic
+        assert current_async_library() == "curio"
+        ran.append(True)
+
+    curio.run(this_is_curio)
+    assert ran == [True]
+
+    with pytest.raises(AsyncLibraryNotFoundError):
+        current_async_library()

test-requirements.txt

@@ -1,2 +1,3 @@
 pytest
 pytest-cov
+curio