storage: add behavior boundary and postgres adapter skeleton

test/parrhesia/storage/behaviour_contracts_test.exs

@@ -0,0 +1,53 @@
+defmodule Parrhesia.Storage.BehaviourContractsTest do
+  use ExUnit.Case, async: true
+
+  test "events behavior exposes expected callbacks" do
+    assert callback_names(Parrhesia.Storage.Events) ==
+             [:count, :delete_by_request, :get_event, :purge_expired, :put_event, :query, :vanish]
+  end
+
+  test "moderation behavior exposes expected callbacks" do
+    assert callback_names(Parrhesia.Storage.Moderation) ==
+             [
+               :allow_pubkey,
+               :ban_event,
+               :ban_pubkey,
+               :block_ip,
+               :disallow_pubkey,
+               :event_banned?,
+               :ip_blocked?,
+               :pubkey_allowed?,
+               :pubkey_banned?,
+               :unban_event,
+               :unban_pubkey,
+               :unblock_ip
+             ]
+  end
+
+  test "groups behavior exposes expected callbacks" do
+    assert callback_names(Parrhesia.Storage.Groups) ==
+             [
+               :delete_membership,
+               :delete_role,
+               :get_membership,
+               :list_memberships,
+               :list_roles,
+               :put_membership,
+               :put_role
+             ]
+  end
+
+  test "admin behavior exposes expected callbacks" do
+    assert callback_names(Parrhesia.Storage.Admin) ==
+             [:append_audit_log, :execute, :list_audit_logs]
+  end
+
+  defp callback_names(behavior_module) do
+    behavior_module
+    |> behaviour_callbacks()
+    |> Enum.map(fn {name, _arity} -> name end)
+    |> Enum.sort()
+  end
+
+  defp behaviour_callbacks(behavior_module), do: behavior_module.behaviour_info(:callbacks)
+end

test/parrhesia/storage_test.exs

@@ -0,0 +1,28 @@
+defmodule Parrhesia.StorageTest do
+  use ExUnit.Case, async: false
+
+  alias Parrhesia.Storage
+
+  test "resolves default storage modules" do
+    assert Storage.events() == Parrhesia.Storage.Adapters.Postgres.Events
+    assert Storage.moderation() == Parrhesia.Storage.Adapters.Postgres.Moderation
+    assert Storage.groups() == Parrhesia.Storage.Adapters.Postgres.Groups
+    assert Storage.admin() == Parrhesia.Storage.Adapters.Postgres.Admin
+  end
+
+  test "raises when configured module does not implement required behavior" do
+    previous = Application.get_env(:parrhesia, :storage, [])
+
+    Application.put_env(:parrhesia, :storage, events: Parrhesia.Config)
+
+    on_exit(fn ->
+      Application.put_env(:parrhesia, :storage, previous)
+    end)
+
+    assert_raise ArgumentError,
+                 ~r/does not implement Parrhesia\.Storage\.Events/,
+                 fn ->
+                   Storage.events()
+                 end
+  end
+end