Add ETS subscription index with candidate narrowing

test/parrhesia/subscriptions/index_test.exs

@@ -0,0 +1,81 @@
+defmodule Parrhesia.Subscriptions.IndexTest do
+  use ExUnit.Case, async: true
+
+  alias Parrhesia.Subscriptions.Index
+
+  test "returns narrowed candidates by kind, author, and tag" do
+    index = start_supervised!(Index)
+    owner = self()
+
+    author = String.duplicate("a", 64)
+
+    filters = [
+      %{
+        "kinds" => [1],
+        "authors" => [author],
+        "#e" => ["event-1"]
+      }
+    ]
+
+    assert :ok = Index.upsert(index, owner, "sub-1", filters)
+
+    matching_event = %{"kind" => 1, "pubkey" => author, "tags" => [["e", "event-1"]]}
+    non_matching_event = %{"kind" => 2, "pubkey" => author, "tags" => [["e", "event-1"]]}
+
+    assert Index.candidate_subscription_keys(index, matching_event) == [{owner, "sub-1"}]
+    assert Index.candidate_subscription_keys(index, non_matching_event) == []
+  end
+
+  test "treats missing kind and tag constraints as wildcards" do
+    index = start_supervised!(Index)
+    owner = self()
+
+    author = String.duplicate("b", 64)
+    filters = [%{"authors" => [author]}]
+
+    assert :ok = Index.upsert(index, owner, "sub-1", filters)
+
+    event = %{"kind" => 7, "pubkey" => author, "tags" => []}
+
+    assert Index.candidate_subscription_keys(index, event) == [{owner, "sub-1"}]
+  end
+
+  test "replaces existing subscription index entries on upsert" do
+    index = start_supervised!(Index)
+    owner = self()
+
+    assert :ok = Index.upsert(index, owner, "sub-1", [%{"kinds" => [1]}])
+    assert :ok = Index.upsert(index, owner, "sub-1", [%{"kinds" => [2]}])
+
+    kind_one_event = %{"kind" => 1, "pubkey" => "any", "tags" => []}
+    kind_two_event = %{"kind" => 2, "pubkey" => "any", "tags" => []}
+
+    assert Index.candidate_subscription_keys(index, kind_one_event) == []
+    assert Index.candidate_subscription_keys(index, kind_two_event) == [{owner, "sub-1"}]
+  end
+
+  test "removes subscriptions when owner process exits" do
+    index = start_supervised!(Index)
+
+    owner =
+      spawn(fn ->
+        receive do
+          :stop -> :ok
+        end
+      end)
+
+    assert :ok = Index.upsert(index, owner, "sub-1", [%{"kinds" => [1]}])
+
+    event = %{"kind" => 1, "pubkey" => "any", "tags" => []}
+    assert Index.candidate_subscription_keys(index, event) == [{owner, "sub-1"}]
+
+    ref = Process.monitor(owner)
+    send(owner, :stop)
+
+    assert_receive {:DOWN, ^ref, :process, ^owner, :normal}
+
+    _state = :sys.get_state(index)
+
+    assert Index.candidate_subscription_keys(index, event) == []
+  end
+end