Test for jinja2_environment_from_request, refs #2225

tests/test_plugins.py

@@ -16,6 +16,7 @@
 from datasette.utils.sqlite import sqlite3
 from datasette.utils import CustomRow, StartupError
 from jinja2.environment import Template
+from jinja2 import ChoiceLoader, FileSystemLoader
 import base64
 import importlib
 import json
@@ -1298,5 +1299,38 @@ def actors_from_ids(self, datasette, actor_ids):
 
 
 @pytest.mark.asyncio
-async def test_hook_jinja2_environment_from_request():
-    pass
+async def test_hook_jinja2_environment_from_request(tmpdir):
+    templates = pathlib.Path(tmpdir / "templates")
+    templates.mkdir()
+    (templates / "index.html").write_text("Hello museums!", "utf-8")
+
+    class EnvironmentPlugin:
+        @hookimpl
+        def jinja2_environment_from_request(self, request, env):
+            if request and request.host == "www.niche-museums.com":
+                return env.overlay(
+                    loader=ChoiceLoader(
+                        [
+                            FileSystemLoader(str(templates)),
+                            env.loader,
+                        ]
+                    ),
+                    enable_async=True,
+                )
+            return env
+
+    datasette = Datasette(memory=True)
+
+    try:
+        pm.register(EnvironmentPlugin(), name="EnvironmentPlugin")
+        response = await datasette.client.get("/")
+        assert response.status_code == 200
+        assert "Hello museums!" not in response.text
+        # Try again with the hostname
+        response2 = await datasette.client.get(
+            "/", headers={"host": "www.niche-museums.com"}
+        )
+        assert response2.status_code == 200
+        assert "Hello museums!" in response2.text
+    finally:
+        pm.unregister(name="EnvironmentPlugin")