Started implementing getIndex, now with TDD (brought to you by DI)!

utils/graph.go

@@ -1,9 +1,27 @@
 package utils
 
-import "github.com/karlkfi/inject"
+import (
+	"github.com/karlkfi/inject"
+	"reflect"
+)
 
 var Graph inject.Graph
 
+var (
+	definitions map[reflect.Type]interface{}
+)
+
+func DefineSingleton(ptr interface{}, constructor interface{}, args ...interface{}) {
+	typ := reflect.TypeOf(ptr)
+	if definitions[typ] == nil {
+		Graph.Define(ptr, inject.NewProvider(constructor, args...))
+	} else {
+		Graph.Define(definitions[typ], inject.NewProvider(constructor, args...))
+	}
+	definitions[typ] = ptr
+}
+
 func init() {
+	definitions = make(map[reflect.Type]interface{})
 	Graph = inject.NewGraph()
 }