diff --git a/testtools/testtools.go b/testtools/testtools.go
index 85c3056..7c3b46c 100644
--- a/testtools/testtools.go
+++ b/testtools/testtools.go
@@ -3,8 +3,10 @@ package testtools
 import (
 	"context"
 	"fmt"
+	"github.com/cyrilix/robocar-base/mqttdevice"
 	"github.com/testcontainers/testcontainers-go"
 	"github.com/testcontainers/testcontainers-go/wait"
+	"sync"
 	"testing"
 )
 
@@ -35,3 +37,24 @@ func MqttContainer(t *testing.T) (context.Context, testcontainers.Container, str
 	mqttUri := fmt.Sprintf("tcp://%s:%d", ip, port.Int())
 	return ctx, mqttC, mqttUri
 }
+
+func NewFakePublisher() *FakePublisher{
+	return &FakePublisher{msg:make(map[string]mqttdevice.MqttValue)}
+}
+
+type FakePublisher struct {
+	muMsg sync.Mutex
+	msg   map[string]mqttdevice.MqttValue
+}
+
+func (f *FakePublisher) Publish(topic string, payload mqttdevice.MqttValue) {
+	f.muMsg.Lock()
+	defer f.muMsg.Unlock()
+	f.msg[topic] = payload
+}
+
+func (f* FakePublisher) PublishedEvent(topic string) mqttdevice.MqttValue{
+	f.muMsg.Lock()
+	defer f.muMsg.Unlock()
+	return f.msg[topic]
+}
diff --git a/testtools/testtools_test.go b/testtools/testtools_test.go
new file mode 100644
index 0000000..e95c6aa
--- /dev/null
+++ b/testtools/testtools_test.go
@@ -0,0 +1,29 @@
+package testtools
+
+import (
+	"github.com/cyrilix/robocar-base/mqttdevice"
+	"testing"
+)
+
+func TestFakePublisher_Publish(t *testing.T) {
+	p := NewFakePublisher()
+
+	cases := []struct {
+		topic string
+		topicPublished string
+		value mqttdevice.MqttValue
+		expected string
+	}{
+		{"test/topic1", "test/topic1", mqttdevice.NewMqttValue(1) , "1" },
+		{"test/topic2", "test/invalid", mqttdevice.NewMqttValue(1) , "" },
+	}
+
+	for _, c := range cases{
+		p.Publish(c.topic, c.value)
+		val := p.PublishedEvent(c.topicPublished)
+		if v, _ := val.StringValue(); v != c.expected {
+			t.Errorf("FakePublisher.Publish(%v, %v): %v, wants %v", c.topic, string(c.value), v, c.expected)
+		}
+
+	}
+}