Synchronisation now shouldn't fail if the trusted host has no new messages

- fixed tests for Gradle builds
- fixed SerializationTest

domain/build.gradle

@@ -10,6 +10,19 @@ uploadArchives {
     }
 }
 
+configurations {
+    testArtifacts.extendsFrom testRuntime
+}
+
+task testJar(type: Jar) {
+    classifier = 'test'
+    from sourceSets.test.output
+}
+
+artifacts {
+    testArtifacts testJar
+}
+
 dependencies {
     compile 'org.slf4j:slf4j-api:1.7.12'
     testCompile 'junit:junit:4.11'