register_commands() plugin hook, closes #1449

tests/test_plugins.py

@@ -6,13 +6,15 @@ from .fixtures import (
     TEMP_PLUGIN_SECRET_FILE,
     TestClient as _TestClient,
 )  # noqa
+from click.testing import CliRunner
 from datasette.app import Datasette
-from datasette import cli
+from datasette import cli, hookimpl
 from datasette.plugins import get_plugins, DEFAULT_PLUGINS, pm
 from datasette.utils.sqlite import sqlite3
 from datasette.utils import CustomRow
 from jinja2.environment import Template
 import base64
+import importlib
 import json
 import os
 import pathlib
@@ -902,3 +904,56 @@ def test_hook_get_metadata(app_client):
     assert "Hello from local metadata" == meta["databases"]["from-local"]["title"]
     assert "Hello from the plugin hook" == meta["databases"]["from-hook"]["title"]
     pm.hook.get_metadata = og_pm_hook_get_metadata
+
+
+def _extract_commands(output):
+    lines = output.split("Commands:\n", 1)[1].split("\n")
+    return {line.split()[0].replace("*", "") for line in lines if line.strip()}
+
+
+def test_hook_register_commands():
+    # Without the plugin should have seven commands
+    runner = CliRunner()
+    result = runner.invoke(cli.cli, "--help")
+    commands = _extract_commands(result.output)
+    assert commands == {
+        "serve",
+        "inspect",
+        "install",
+        "package",
+        "plugins",
+        "publish",
+        "uninstall",
+    }
+
+    # Now install a plugin
+    class VerifyPlugin:
+        __name__ = "VerifyPlugin"
+
+        @hookimpl
+        def register_commands(self, cli):
+            @cli.command()
+            def verify():
+                pass
+
+            @cli.command()
+            def unverify():
+                pass
+
+    pm.register(VerifyPlugin(), name="verify")
+    importlib.reload(cli)
+    result2 = runner.invoke(cli.cli, "--help")
+    commands2 = _extract_commands(result2.output)
+    assert commands2 == {
+        "serve",
+        "inspect",
+        "install",
+        "package",
+        "plugins",
+        "publish",
+        "uninstall",
+        "verify",
+        "unverify",
+    }
+    pm.unregister(name="verify")
+    importlib.reload(cli)