diff --git a/engine/libcdre_it_test.go b/engine/libcdre_it_test.go
new file mode 100644
index 000000000..e7f557477
--- /dev/null
+++ b/engine/libcdre_it_test.go
@@ -0,0 +1,56 @@
+// +build integration
+
+/*
+Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
+Copyright (C) ITsysCOM GmbH
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+package engine
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/cgrates/cgrates/config"
+)
+
+func TestWriteFailedPosts(t *testing.T) {
+	// can't convert
+	var notanExportEvent string
+	writeFailedPosts("somestring", notanExportEvent)
+	// can convert & write
+	dir := "/tmp/engine/libcdre_test/"
+	exportEvent := &ExportEvents{
+		module: "module",
+	}
+	if err := os.RemoveAll(dir); err != nil {
+		t.Fatal("Error removing folder: ", dir, err)
+	}
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		t.Fatal("Error creating folder: ", dir, err)
+	}
+	config.CgrConfig().GeneralCfg().FailedPostsDir = dir
+	writeFailedPosts("itmID", exportEvent)
+
+	if filename, err := filepath.Glob(filepath.Join(dir, "*.gob")); err != nil {
+		t.Error(err)
+	} else if len(filename) == 0 {
+		t.Error("Expecting one file")
+	} else if len(filename) > 1 {
+		t.Error("Expecting only one file")
+	}
+}
diff --git a/sessions/sessions_test.go b/sessions/sessions_test.go
index 82766a8d7..6663dcb43 100644
--- a/sessions/sessions_test.go
+++ b/sessions/sessions_test.go
@@ -55,6 +55,35 @@ var attrs = &engine.AttrSProcessEventReply{
 	},
 }
 
+func TestIsIndexed(t *testing.T) {
+	sS := &SessionS{}
+	if sS.isIndexed(&Session{CGRID: "test"}, true) {
+		t.Error("Expecting: false, received: true")
+	}
+	if sS.isIndexed(&Session{CGRID: "test"}, false) {
+		t.Error("Expecting: false, received: true")
+	}
+	sS = &SessionS{
+		aSessions: map[string]*Session{"test": &Session{CGRID: "test"}},
+	}
+	if !sS.isIndexed(&Session{CGRID: "test"}, false) {
+		t.Error("Expecting: true, received: false")
+	}
+	if sS.isIndexed(&Session{CGRID: "test"}, true) {
+		t.Error("Expecting: true, received: false")
+	}
+
+	sS = &SessionS{
+		pSessions: map[string]*Session{"test": &Session{CGRID: "test"}},
+	}
+	if !sS.isIndexed(&Session{CGRID: "test"}, true) {
+		t.Error("Expecting: false, received: true")
+	}
+	if sS.isIndexed(&Session{CGRID: "test"}, false) {
+		t.Error("Expecting: false, received: true")
+	}
+}
+
 func TestSessionSIndexAndUnindexSessions(t *testing.T) {
 	sSCfg, _ := config.NewDefaultCGRConfig()
 	sSCfg.SessionSCfg().SessionIndexes = utils.StringMap{
diff --git a/utils/set_test.go b/utils/set_test.go
new file mode 100644
index 000000000..c1e45476f
--- /dev/null
+++ b/utils/set_test.go
@@ -0,0 +1,84 @@
+/*
+Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
+Copyright (C) ITsysCOM GmbH
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+package utils
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestNewStringSet(t *testing.T) {
+	input := []string{}
+	exp := &StringSet{data: make(map[string]struct{})}
+	if rcv := NewStringSet(input); !reflect.DeepEqual(rcv, exp) {
+		t.Errorf("Expected: %+v, received: %+v", exp, rcv)
+	}
+	input = []string{"test"}
+	exp.AddSlice(input)
+	if rcv := NewStringSet(input); !reflect.DeepEqual(rcv, exp) {
+		t.Errorf("Expected: %+v, received: %+v", exp, rcv)
+	}
+	input = []string{"test1", "test2", "test3"}
+	exp = &StringSet{data: make(map[string]struct{})}
+	exp.AddSlice(input)
+	if rcv := NewStringSet(input); !reflect.DeepEqual(rcv, exp) {
+		t.Errorf("Expected: %+v, received: %+v", exp, rcv)
+	}
+}
+
+func TestAdd(t *testing.T){
+	s := &StringSet{data: map[string]struct{}{}}
+	eOut := &StringSet{data: map[string]struct{}{
+		"test" : struct{}{},
+	}}
+	if reflect.DeepEqual(eOut,s){
+		t.Errorf("Expecting: %+v, received: %+v",eOut,s)
+	}
+	s.Add("test")
+	if !reflect.DeepEqual(eOut,s){
+		t.Errorf("Expecting: %+v, received: %+v",eOut,s)
+	}
+}
+
+func TestRemove(t *testing.T){
+	eOut := &StringSet{data: map[string]struct{}{}}
+	s := &StringSet{data: map[string]struct{}{
+		"test" : struct{}{},
+	}}
+	if reflect.DeepEqual(eOut,s){
+		t.Errorf("Expecting: %+v, received: %+v",eOut,s)
+	}
+	s.Remove("test")
+	if !reflect.DeepEqual(eOut,s){
+		t.Errorf("Expecting: %+v, received: %+v",eOut,s)
+	}
+}
+
+func TestHas(t *testing.T){
+	s := &StringSet{}
+	if s.Has("test"){
+		t.Error("Expecting: false, received: true")
+	}
+	s = &StringSet{data: map[string]struct{}{
+		"test" : struct{}{},
+	}}
+	if !s.Has("test"){
+		t.Error("Expecting: true, received: false")
+	}
+}
\ No newline at end of file