Added documentation

docs/tutorial/async-cmd.md

@@ -0,0 +1,40 @@
+Typer allows you to use [async](https://docs.python.org/3/library/asyncio.html) functions.
+
+```Python
+{!../docs_src/async_cmd/async001.py!}
+```
+
+<div class="termy">
+
+```console
+$ python async.py 
+
+Hello Async World
+```
+
+</div>
+
+It also works with commands, and you can mix regular and async commands:
+
+```Python
+{!../docs_src/async_cmd/async002.py!}
+```
+
+<div class="termy">
+
+```console
+$ python async.py sync
+
+Hello Sync World
+
+$ python async.py async
+
+Hello Async World
+```
+</div>
+
+!!! info
+    Under the hood, Typer is running your async functions with [asyncio.run()](https://docs.python.org/3/library/asyncio-runner.html#asyncio.run)
+
+!!! warning
+    Typer only supports async functions on Python 3.7+

docs_src/async_cmd/async001.py

@@ -0,0 +1,13 @@
+import asyncio
+import typer
+
+app = typer.Typer()
+
+
+async def main():
+    await asyncio.sleep(0)
+    print("Hello Async World")
+
+
+if __name__ == "__main__":
+    typer.run(main)

docs_src/async_cmd/async002.py

@@ -0,0 +1,19 @@
+import asyncio
+import typer
+
+app = typer.Typer()
+
+
+@app.command("sync")
+def command_sync():
+    print("Hello Sync World")
+
+
+@app.command("async")
+async def command_async():
+    await asyncio.sleep(0)
+    print("Hello Async World")
+
+
+if __name__ == "__main__":
+    app()

mkdocs.yml

@@ -50,6 +50,7 @@ nav:
           - Typer Callback: tutorial/commands/callback.md
           - One or Multiple Commands: tutorial/commands/one-or-multiple.md
           - Using the Context: tutorial/commands/context.md
+      - Asynchronous functions: tutorial/async-cmd.md
       - CLI Option autocompletion: tutorial/options-autocompletion.md
       - CLI Parameter Types:
           - CLI Parameter Types Intro: tutorial/parameter-types/index.md

tests/test_tutorial/test_async_cmd/test_async001.py

@@ -0,0 +1,38 @@
+import subprocess
+import sys
+import pytest
+
+import typer
+from typer.testing import CliRunner
+
+from docs_src.async_cmd import async001 as mod
+
+runner = CliRunner()
+
+@pytest.mark.skipif(sys.version_info < (3, 7), reason="typer support for async functions requires python3.7 or higher")
+def test_cli():
+    app = typer.Typer()
+    app.command()(mod.main)
+    result = runner.invoke(app, [])
+    assert result.output == "Hello Async World\n"
+
+
+@pytest.mark.skipif(sys.version_info < (3, 7), reason="typer support for async functions requires python3.7 or higher")
+def test_execute():
+    result = subprocess.run(
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    assert result.stdout == "Hello Async World\n"
+
+
+def test_script():
+    result = subprocess.run(
+        [sys.executable, "-m", "coverage", "run", mod.__file__, "--help"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    assert "Usage" in result.stdout

tests/test_tutorial/test_async_cmd/test_async002.py

@@ -0,0 +1,53 @@
+import subprocess
+import sys
+import pytest
+
+import typer
+from typer.testing import CliRunner
+
+from docs_src.async_cmd import async002 as mod
+
+app = mod.app
+
+runner = CliRunner()
+
+def test_command_sync():
+    result = runner.invoke(app, ["sync"])
+    assert result.output == "Hello Sync World\n"
+
+
+@pytest.mark.skipif(sys.version_info < (3, 7), reason="typer support for async functions requires python3.7 or higher")
+def test_command_async():
+    result = runner.invoke(app, ["async"])
+    assert result.output == "Hello Async World\n"
+
+
+def test_execute_sync():
+    result = subprocess.run(
+        [sys.executable, "-m", "coverage", "run", mod.__file__, "sync"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    assert result.stdout == "Hello Sync World\n"
+
+
+@pytest.mark.skipif(sys.version_info < (3, 7), reason="typer support for async functions requires python3.7 or higher")
+def test_execute_async():
+    result = subprocess.run(
+        [sys.executable, "-m", "coverage", "run", mod.__file__, "async"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    assert result.stdout == "Hello Async World\n"
+
+
+def test_script():
+    result = subprocess.run(
+        [sys.executable, "-m", "coverage", "run", mod.__file__, "--help"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf-8",
+    )
+    assert "Usage" in result.stdout