docs
| id | page | ref | title | content | breadcrumbs | references |
|---|---|---|---|---|---|---|
| testing_plugins:testing-plugins-datasette-test-instance | testing_plugins | testing-plugins-datasette-test-instance | Setting up a Datasette test instance | The above example shows the easiest way to start writing tests against a Datasette instance: from datasette.app import Datasette import pytest @pytest.mark.asyncio async def test_plugin_is_installed(): datasette = Datasette(memory=True) response = await datasette.client.get("/-/plugins.json") assert response.status_code == 200 Creating a Datasette() instance like this as useful shortcut in tests, but there is one detail you need to be aware of. It's important to ensure that the async method .invoke_startup() is called on that instance. You can do that like this: datasette = Datasette(memory=True) await datasette.invoke_startup() This method registers any startup(datasette) or prepare_jinja2_environment(env, datasette) plugins that might themselves need to make async calls. If you are using await datasette.client.get() and similar methods then you don't need to worry about this - Datasette automatically calls invoke_startup() the first time it handles a request. | ["Testing plugins"] | [] |
| testing_plugins:testing-datasette-client | testing_plugins | testing-datasette-client | Using datasette.client in tests | The datasette.client mechanism is designed for use in tests. It provides access to a pre-configured HTTPX async client instance that can make GET, POST and other HTTP requests against a Datasette instance from inside a test. A simple test looks like this: @pytest.mark.asyncio async def test_homepage(): ds = Datasette(memory=True) response = await ds.client.get("/") html = response.text assert "<h1>" in html Or for a JSON API: @pytest.mark.asyncio async def test_actor_is_null(): ds = Datasette(memory=True) response = await ds.client.get("/-/actor.json") assert response.json() == {"actor": None} To make requests as an authenticated actor, create a signed ds_cookie using the datasette.client.actor_cookie() helper function and pass it in cookies= like this: @pytest.mark.asyncio async def test_signed_cookie_actor(): ds = Datasette(memory=True) cookies = {"ds_actor": ds.client.actor_cookie({"id": "root"})} response = await ds.client.get("/-/actor.json", cookies=cookies) assert response.json() == {"actor": {"id": "root"}} | ["Testing plugins"] | [{"href": "https://www.python-httpx.org/async/", "label": "HTTPX async client"}] |
| testing_plugins:testing-plugins-pdb | testing_plugins | testing-plugins-pdb | Using pdb for errors thrown inside Datasette | If an exception occurs within Datasette itself during a test, the response returned to your plugin will have a response.status_code value of 500. You can add pdb=True to the Datasette constructor to drop into a Python debugger session inside your test run instead of getting back a 500 response code. This is equivalent to running the datasette command-line tool with the --pdb option. Here's what that looks like in a test function: def test_that_opens_the_debugger_or_errors(): ds = Datasette([db_path], pdb=True) response = await ds.client.get("/") If you use this pattern you will need to run pytest with the -s option to avoid capturing stdin/stdout in order to interact with the debugger prompt. | ["Testing plugins"] | [] |
| testing_plugins:testing-plugins-fixtures | testing_plugins | testing-plugins-fixtures | Using pytest fixtures | Pytest fixtures can be used to create initial testable objects which can then be used by multiple tests. A common pattern for Datasette plugins is to create a fixture which sets up a temporary test database and wraps it in a Datasette instance. Here's an example that uses the sqlite-utils library to populate a temporary test database. It also sets the title of that table using a simulated metadata.json configuration: from datasette.app import Datasette import pytest import sqlite_utils @pytest.fixture(scope="session") def datasette(tmp_path_factory): db_directory = tmp_path_factory.mktemp("dbs") db_path = db_directory / "test.db" db = sqlite_utils.Database(db_path) db["dogs"].insert_all( [ {"id": 1, "name": "Cleo", "age": 5}, {"id": 2, "name": "Pancakes", "age": 4}, ], pk="id", ) datasette = Datasette( [db_path], metadata={ "databases": { "test": { "tables": { "dogs": {"title": "Some dogs"} } } } }, ) return datasette @pytest.mark.asyncio async def test_example_table_json(datasette): response = await datasette.client.get( "/test/dogs.json?_shape=array" ) assert response.status_code == 200 assert response.json() == [ {"id": 1, "name": "Cleo", "age": 5}, {"id": 2, "name": "Pancakes", "age": 4}, ] @pytest.mark.asyncio async def test_example_table_html(datasette): response = await datasette.client.get("/test/dogs") assert ">Some dogs</h1>" in response.text Here the datasette() function defines the fixture, which is than automatically passed to the two test functions based on pytest automatically matching their datasette function parameters. The @pytest.fixture(scope="session") line here ensures the fixture is reused for the full pytest execution session. This… | ["Testing plugins"] | [{"href": "https://docs.pytest.org/en/stable/fixture.html", "label": "Pytest fixtures"}, {"href": "https://sqlite-utils.datasette.io/en/stable/python-api.html", "label": "sqlite-utils library"}] |
| testing_plugins:testing-plugins-pytest-httpx | testing_plugins | testing-plugins-pytest-httpx | Testing outbound HTTP calls with pytest-httpx | If your plugin makes outbound HTTP calls - for example datasette-auth-github or datasette-import-table - you may need to mock those HTTP requests in your tests. The pytest-httpx package is a useful library for mocking calls. It can be tricky to use with Datasette though since it mocks all HTTPX requests, and Datasette's own testing mechanism uses HTTPX internally. To avoid breaking your tests, you can return ["localhost"] from the non_mocked_hosts() fixture. As an example, here's a very simple plugin which executes an HTTP response and returns the resulting content: from datasette import hookimpl from datasette.utils.asgi import Response import httpx @hookimpl def register_routes(): return [ (r"^/-/fetch-url$", fetch_url), ] async def fetch_url(datasette, request): if request.method == "GET": return Response.html( """ <form action="/-/fetch-url" method="post"> <input type="hidden" name="csrftoken" value="{}"> <input name="url"><input type="submit"> </form>""".format( request.scope["csrftoken"]() ) ) vars = await request.post_vars() url = vars["url"] return Response.text(httpx.get(url).text) Here's a test for that plugin that mocks the HTTPX outbound request: from datasette.app import Datasette import pytest @pytest.fixture def non_mocked_hosts(): # This ensures httpx-mock will not affect Datasette's own # httpx calls made in the tests by datasette.client: return ["localhost"] async def test_outbound_http_call(httpx_mock): httpx_mock.add_response( url="https://www.example.com/", text="Hello world", ) datasette = Datasette([], memory=True) response = await datasette.client.post( "/-/fetch-url", data={"url": "https://www.example.com/"}, ) assert response.text == "Hello world" outbound_request = httpx_mock.get_request()… | ["Testing plugins"] | [{"href": "https://pypi.org/project/pytest-httpx/", "label": "pytest-httpx"}] |
| testing_plugins:testing-plugins-register-in-test | testing_plugins | testing-plugins-register-in-test | Registering a plugin for the duration of a test | When writing tests for plugins you may find it useful to register a test plugin just for the duration of a single test. You can do this using pm.register() and pm.unregister() like this: from datasette import hookimpl from datasette.app import Datasette from datasette.plugins import pm import pytest @pytest.mark.asyncio async def test_using_test_plugin(): class TestPlugin: __name__ = "TestPlugin" # Use hookimpl and method names to register hooks @hookimpl def register_routes(self): return [ (r"^/error$", lambda: 1 / 0), ] pm.register(TestPlugin(), name="undo") try: # The test implementation goes here datasette = Datasette() response = await datasette.client.get("/error") assert response.status_code == 500 finally: pm.unregister(name="undo") To reuse the same temporary plugin in multiple tests, you can register it inside a fixture in your conftest.py file like this: from datasette import hookimpl from datasette.app import Datasette from datasette.plugins import pm import pytest import pytest_asyncio @pytest_asyncio.fixture async def datasette_with_plugin(): class TestPlugin: __name__ = "TestPlugin" @hookimpl def register_routes(self): return [ (r"^/error$", lambda: 1 / 0), ] pm.register(TestPlugin(), name="undo") try: yield Datasette() finally: pm.unregister(name="undo") Note the yield statement here - this ensures that the finally: block that unregisters the plugin is executed only after the test function itself has completed. Then in a test: @pytest.mark.asyncio async def test_error(datasette_with_plugin): response = await datasette_with_plugin.client.get("/error") assert response.status_code == 500 | ["Testing plugins"] | [] |