response.set_cookie(), closes #795

tests/test_internals_response.py

@@ -1,4 +1,5 @@
 from datasette.utils.asgi import Response
+import pytest
 
 
 def test_response_html():
@@ -26,3 +27,28 @@ def test_response_redirect():
     response = Response.redirect("/foo")
     assert 302 == response.status
     assert "/foo" == response.headers["Location"]
+
+
+@pytest.mark.asyncio
+async def test_response_set_cookie():
+    events = []
+
+    async def send(event):
+        events.append(event)
+
+    response = Response.redirect("/foo")
+    response.set_cookie("foo", "bar", max_age=10, httponly=True)
+    await response.asgi_send(send)
+
+    assert [
+        {
+            "type": "http.response.start",
+            "status": 302,
+            "headers": [
+                [b"Location", b"/foo"],
+                [b"content-type", b"text/plain"],
+                [b"set-cookie", b"foo=bar; HttpOnly; Max-Age=10; Path=/; SameSite=lax"],
+            ],
+        },
+        {"type": "http.response.body", "body": b""},
+    ] == events