Added a new layer: engine (equivalent to use cases in Clean Architecture). Should make testing things easier

utils/graph.go

@@ -11,7 +11,7 @@ var (
 	definitions map[reflect.Type]interface{}
 )
 
-func DefineSingleton(ptr interface{}, constructor interface{}, args ...interface{}) {
+func DefineSingleton(ptr interface{}, constructor interface{}, args ...interface{}) interface{} {
 	typ := reflect.TypeOf(ptr)
 	provider := inject.NewProvider(constructor, args...)
 
@@ -21,6 +21,7 @@ func DefineSingleton(ptr interface{}, constructor interface{}, args ...interface
 		definitions[typ] = ptr
 	}
 	Graph.Define(ptr, provider)
+	return ptr
 }
 
 func init() {

utils/time.go

@@ -0,0 +1,11 @@
+package utils
+
+import "time"
+
+func ToTime(millis int64) time.Time {
+	return time.Unix(0, millis*int64(time.Millisecond))
+}
+
+func ToMillis(t time.Time) int64 {
+	return t.UnixNano() / int64(time.Millisecond)
+}