diff --git a/.formatter.exs b/.formatter.exs
index 3deae447..6ed409c0 100644
--- a/.formatter.exs
+++ b/.formatter.exs
@@ -1,3 +1,5 @@
+# Used by "mix format"
+
 locals_without_parens = [
   dispatch: 2,
   identify: 2,
@@ -6,8 +8,8 @@ locals_without_parens = [
 
 [
   inputs: [
-    "lib/*/{lib,test}/**/*.{ex,exs}",
-    "lib/*/mix.exs"
+    "{mix,.formatter}.exs",
+    "{config,lib,test}/**/*.{ex,exs}"
   ],
   locals_without_parens: locals_without_parens,
   export: [locals_without_parens: locals_without_parens]
diff --git a/lib/commanded/event_store/adapters/in_memory/subscription.ex b/lib/commanded/event_store/adapters/in_memory/subscription.ex
index 29712be4..87bcfb2f 100644
--- a/lib/commanded/event_store/adapters/in_memory/subscription.ex
+++ b/lib/commanded/event_store/adapters/in_memory/subscription.ex
@@ -34,7 +34,7 @@ defmodule Commanded.EventStore.Adapters.InMemory.Subscription do
   end
 
   @impl GenServer
-  def handle_info({:DOWN, _ref, :process, pid, reason}, %Subscription{} = state) do
+  def handle_info({:DOWN, _ref, :process, _pid, reason}, %Subscription{} = state) do
     {:stop, reason, state}
   end
 end
diff --git a/test/event_store/support/append_events_test_case.ex b/test/event_store/support/append_events_test_case.ex
index 144a26de..f2d8ea52 100644
--- a/test/event_store/support/append_events_test_case.ex
+++ b/test/event_store/support/append_events_test_case.ex
@@ -13,13 +13,13 @@ defmodule Commanded.EventStore.AppendEventsTestCase do
 
     describe "append events to a stream" do
       test "should append events" do
-        assert :ok == EventStore.append_to_stream("stream", 0, build_events(2))
-        assert :ok == EventStore.append_to_stream("stream", 2, build_events(2))
-        assert :ok == EventStore.append_to_stream("stream", 4, build_events(1))
+        assert :ok == EventStore.append_to_stream("stream", 0, build_events(1))
+        assert :ok == EventStore.append_to_stream("stream", 1, build_events(2))
+        assert :ok == EventStore.append_to_stream("stream", 3, build_events(3))
       end
 
-      test "should append events without checking expected version" do
-        assert :ok == EventStore.append_to_stream("stream", :any_version, build_events(2))
+      test "should append events with `:any_version` without checking expected version" do
+        assert :ok == EventStore.append_to_stream("stream", :any_version, build_events(3))
         assert :ok == EventStore.append_to_stream("stream", :any_version, build_events(2))
         assert :ok == EventStore.append_to_stream("stream", :any_version, build_events(1))
       end
@@ -35,34 +35,34 @@ defmodule Commanded.EventStore.AppendEventsTestCase do
                  EventStore.append_to_stream("stream", :no_stream, build_events(1))
       end
 
-      test "should append events with :stream_exists parameter" do
+      test "should append events with `:stream_exists` parameter" do
         assert :ok == EventStore.append_to_stream("stream", :no_stream, build_events(2))
         assert :ok == EventStore.append_to_stream("stream", :stream_exists, build_events(1))
       end
 
-      test "should fail when stream does not exists with :stream_exists parameter" do
+      test "should fail with `:stream_exists` parameter when stream does not exist" do
         assert {:error, :stream_does_not_exist} ==
                  EventStore.append_to_stream("stream", :stream_exists, build_events(1))
       end
 
-      test "should fail to append to a stream because of wrong expected version when no previous events" do
-        events = build_events(1)
-
+      test "should fail to append to a stream because of wrong expected version when no stream" do
         assert {:error, :wrong_expected_version} ==
-                 EventStore.append_to_stream("stream", 1, events)
+                 EventStore.append_to_stream("stream", 1, build_events(1))
       end
 
       test "should fail to append to a stream because of wrong expected version" do
-        assert :ok == EventStore.append_to_stream("stream", 0, build_events(2))
+        assert :ok == EventStore.append_to_stream("stream", 0, build_events(3))
+
+        assert {:error, :wrong_expected_version} ==
+                 EventStore.append_to_stream("stream", 0, build_events(1))
 
         assert {:error, :wrong_expected_version} ==
                  EventStore.append_to_stream("stream", 1, build_events(1))
-      end
 
-      test "should append events to any version" do
-        assert :ok == EventStore.append_to_stream("stream", :any_version, build_events(2))
-        assert :ok == EventStore.append_to_stream("stream", :any_version, build_events(2))
-        assert :ok == EventStore.append_to_stream("stream", :any_version, build_events(1))
+        assert {:error, :wrong_expected_version} ==
+                 EventStore.append_to_stream("stream", 2, build_events(1))
+
+        assert :ok == EventStore.append_to_stream("stream", 3, build_events(1))
       end
     end