Added unit tests for canary message (#75)

Signed-off-by: Paolo Patierno <[email protected]>

internal/services/canary_message_test.go

@@ -0,0 +1,52 @@
+//
+// Copyright Strimzi authors.
+// License: Apache License 2.0 (see the file LICENSE or http://apache.org/licenses/LICENSE-2.0.html).
+//
+
+// Package services defines an interface for canary services and related implementations
+package services
+
+import (
+	"testing"
+
+	"github.com/Shopify/sarama"
+)
+
+func TestCanaryMessage(t *testing.T) {
+	cm := CanaryMessage{
+		ProducerID: "producer-id",
+		MessageID:  0,
+		Timestamp:  12345,
+	}
+	want := "{\"producerId\":\"producer-id\",\"messageId\":0,\"timestamp\":12345}"
+	if cm.Json() != want {
+		t.Errorf("JSON got = %s, want = %s", cm.Json(), want)
+	}
+}
+
+func TestCanaryMessageEncode(t *testing.T) {
+	cm := CanaryMessage{
+		ProducerID: "producer-id",
+		MessageID:  0,
+		Timestamp:  12345,
+	}
+	encoder := sarama.StringEncoder(cm.Json())
+	bytes, _ := encoder.Encode()
+
+	decodedCm := NewCanaryMessage(bytes)
+
+	if cm != decodedCm {
+		t.Errorf("got = %v, want = %v", decodedCm, cm)
+	}
+
+	wrong := "{\"producerId\":\"producer-id\",\"messageId\":1,\"timestamp\":67890}"
+
+	encoder = sarama.StringEncoder(wrong)
+	bytes, _ = encoder.Encode()
+
+	decodedCm = NewCanaryMessage(bytes)
+
+	if cm == decodedCm {
+		t.Errorf("got %v should be different from %v", decodedCm, cm)
+	}
+}