chore: separate pubsub into a new package (#8017)

* chore: rename store to dbmock for consistency

* chore: remove redundant dbtype package

This wasn't necessary and forked how we do DB types.

* chore: separate pubsub into a new package

This didn't need to be in database and was bloating it.

coderd/database/pubsub/pubsub_memory_test.go

@@ -0,0 +1,56 @@
+package pubsub_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/coderd/database/pubsub"
+)
+
+func TestPubsubMemory(t *testing.T) {
+	t.Parallel()
+
+	t.Run("Legacy", func(t *testing.T) {
+		t.Parallel()
+
+		pubsub := pubsub.NewInMemory()
+		event := "test"
+		data := "testing"
+		messageChannel := make(chan []byte)
+		cancelFunc, err := pubsub.Subscribe(event, func(ctx context.Context, message []byte) {
+			messageChannel <- message
+		})
+		require.NoError(t, err)
+		defer cancelFunc()
+		go func() {
+			err = pubsub.Publish(event, []byte(data))
+			assert.NoError(t, err)
+		}()
+		message := <-messageChannel
+		assert.Equal(t, string(message), data)
+	})
+
+	t.Run("WithErr", func(t *testing.T) {
+		t.Parallel()
+
+		pubsub := pubsub.NewInMemory()
+		event := "test"
+		data := "testing"
+		messageChannel := make(chan []byte)
+		cancelFunc, err := pubsub.SubscribeWithErr(event, func(ctx context.Context, message []byte, err error) {
+			assert.NoError(t, err) // memory pubsub never sends errors.
+			messageChannel <- message
+		})
+		require.NoError(t, err)
+		defer cancelFunc()
+		go func() {
+			err = pubsub.Publish(event, []byte(data))
+			assert.NoError(t, err)
+		}()
+		message := <-messageChannel
+		assert.Equal(t, string(message), data)
+	})
+}