Extract method getMesosDnsId and add a few tests. Still learning Conv…

…ey syntax

services/marathon/marathon.go

@@ -194,21 +194,10 @@ func createApps(tasksById map[string]marathonTaskList, marathonApps map[string]m
 			appPath = "/" + appId
 		}
 
-		// split up groups and recombine for how mesos-dns/consul/etc use service name
-		//   "/nested/group/app" -> "app-group-nested"
-		groups := strings.Split(appPath, "/")
-		reverseGroups := []string{}
-		for i := len(groups) - 1; i >= 0; i-- {
-			if groups[i] != "" {
-				reverseGroups = append(reverseGroups, groups[i])
-			}
-		}
-		mesosId := strings.Join(reverseGroups, "-")
-
 		// build App from marathonApp
 		app := App{
 			Id:              appPath,
-			MesosDnsId:      mesosId,
+			MesosDnsId:      getMesosDnsId(appPath),
 			EscapedId:       strings.Replace(appId, "/", "::", -1),
 			HealthCheckPath: parseHealthCheckPath(mApp.HealthChecks),
 			Env:             mApp.Env,
@@ -249,6 +238,19 @@ func createApps(tasksById map[string]marathonTaskList, marathonApps map[string]m
 	return apps
 }
 
+func getMesosDnsId(appPath string) string {
+	// split up groups and recombine for how mesos-dns/consul/etc use service name
+	//   "/nested/group/app" -> "app-group-nested"
+	groups := strings.Split(appPath, "/")
+	reverseGroups := []string{}
+	for i := len(groups) - 1; i >= 0; i-- {
+		if groups[i] != "" {
+			reverseGroups = append(reverseGroups, groups[i])
+		}
+	}
+	return strings.Join(reverseGroups, "-")
+}
+
 func parseHealthCheckPath(checks []marathonHealthCheck) string {
 	for _, check := range checks {
 		if check.Protocol != "HTTP" {

services/marathon/marathon_test.go

@@ -5,6 +5,26 @@ import (
 	"testing"
 )
 
+func TestGetMesosDnsId_Simple(t *testing.T) {
+	Convey("#getMesosDnsId", t, func() {
+		Convey("should return simple appname", func() {
+			So(getMesosDnsId("appname"), ShouldEqual, "appname")
+		})
+
+		Convey("should return simple appname if slash prefixed", func() {
+			So(getMesosDnsId("/appname"), ShouldEqual, "appname")
+		})
+
+		Convey("should return groups reverse-added to appname", func() {
+			So(getMesosDnsId("/group/appname"), ShouldEqual, "appname-group")
+		})
+
+		Convey("should return groups reverse-added to appname but no blanks", func() {
+			So(getMesosDnsId("//group/again//appname/"), ShouldEqual, "appname-again-group")
+		})
+	})
+}
+
 func TestParseHealthCheckPathTCP(t *testing.T) {
 	Convey("#parseHealthCheckPath", t, func() {
 		checks := []marathonHealthCheck{