Add subscription cancellation for QQuickGrpcSubscription

Fixes: #146

src/grpc/quick/qquickgrpcsubscription.cpp

@@ -40,6 +40,9 @@ QQuickGrpcSubscription::QQuickGrpcSubscription(QObject *parent) : QObject(parent
 
 QQuickGrpcSubscription::~QQuickGrpcSubscription()
 {
+    if (!m_subscription.isNull()) {
+        m_subscription->cancel();
+    }
     delete m_returnValue;
 }
 

tests/test_grpc_qml/qml/tst_grpc.qml

@@ -103,6 +103,29 @@ TestCase {
         }
     }
 
+    Loader {
+        id: subscriptionLoader
+        active: false
+        sourceComponent: Component {
+            GrpcSubscription {
+                property bool ok: true
+                property int updateCount: 0
+                enabled: true
+                client: TestServiceClient
+                method: "testMethodServerStream"
+                argument: stringMsg
+                onUpdated: {
+                    ++updateCount;
+                    ok = ok && value.testFieldString === ("Test string" + updateCount)
+                }
+                onError: {
+                    console.log("Subscription error: " + status.code + " " + status.message)
+                    ok = false;
+                }
+            }
+        }
+    }
+
     function test_stringEchoTest() {
         var called = false;
         var errorCalled = false;
@@ -175,4 +198,12 @@ TestCase {
         wait(300)
         compare(called && !errorCalled, true, "testMethodNonCompatibleArgRet was not called proper way")
     }
+
+    function test_1loader() {//This test has to be called first to fail other tests in case if it fails
+        subscriptionLoader.active = true;
+        wait(1500);
+        compare(subscriptionLoader.item.ok, true, "Subscription data failed")
+        compare(subscriptionLoader.item.updateCount, 1, "Subscription failed, update was not called right amount times")
+        subscriptionLoader.active = false;
+    }
 }