Ported setup.py to pyproject.toml (#2555)

* Ported setup.py to pyproject.toml, refs #2553

* Make fixtures tests less flaky

The in-memory fixtures table was being shared between different
instances of the test client, leading to occasional errors when
running the full test suite.

docs/contributing.rst

@@ -42,7 +42,7 @@ The next step is to create a virtual environment for your project and use it to
     # Install Datasette and its testing dependencies
     python3 -m pip install -e '.[test]'
 
-That last line does most of the work: ``pip install -e`` means "install this package in a way that allows me to edit the source code in place". The ``.[test]`` option means "use the setup.py in this directory and install the optional testing dependencies as well".
+That last line does most of the work: ``pip install -e`` means "install this package in a way that allows me to edit the source code in place". The ``.[test]`` option means "install the optional testing dependencies as well".
 
 .. _contributing_running_tests:
 
@@ -160,7 +160,7 @@ If any of your code does not conform to Black you can run this to automatically
 
 ::
 
-    reformatted ../datasette/setup.py
+    reformatted ../datasette/app.py
     All done! ✨ 🍰 ✨
     1 file reformatted, 94 files left unchanged.
 

docs/plugin_hooks.rst

@@ -691,7 +691,7 @@ Help text (from the docstring for the function plus any defined Click arguments
 
 Plugins can register multiple commands by making multiple calls to the ``@cli.command()`` decorator. Consult the `Click documentation <https://click.palletsprojects.com/>`__ for full details on how to build a CLI command, including how to define arguments and options.
 
-Note that ``register_commands()`` plugins cannot used with the :ref:`--plugins-dir mechanism <writing_plugins_one_off>` - they need to be installed into the same virtual environment as Datasette using ``pip install``. Provided it has a ``setup.py`` file (see :ref:`writing_plugins_packaging`) you can run ``pip install`` directly against the directory in which you are developing your plugin like so::
+Note that ``register_commands()`` plugins cannot used with the :ref:`--plugins-dir mechanism <writing_plugins_one_off>` - they need to be installed into the same virtual environment as Datasette using ``pip install``. Provided it has a ``pyproject.toml`` file (see :ref:`writing_plugins_packaging`) you can run ``pip install`` directly against the directory in which you are developing your plugin like so::
 
     pip install -e path/to/my/datasette-plugin
 

docs/testing_plugins.rst

@@ -33,16 +33,16 @@ You can install these packages like so::
 
     pip install pytest pytest-asyncio
 
-If you are building an installable package you can add them as test dependencies to your ``setup.py`` module like this:
+If you are building an installable package you can add them as test dependencies to your ``pyproject.toml`` file like this:
 
-.. code-block:: python
+.. code-block:: toml
 
-    setup(
-        name="datasette-my-plugin",
-        # ...
-        extras_require={"test": ["pytest", "pytest-asyncio"]},
-        tests_require=["datasette-my-plugin[test]"],
-    )
+    [project]
+    name = "datasette-my-plugin"
+    # ...
+
+    [project.optional-dependencies]
+    test = ["pytest", "pytest-asyncio"]
 
 You can then install the test dependencies like so::