Fix Issue paceholder#127 (paceholder#140)

* Fix Issue paceholder#127

* add unit test

Author: Quincunx271

src/NodeGraphicsObject.cpp

@@ -233,24 +233,26 @@ mousePressEvent(QGraphicsSceneMouseEvent * event)
         }
         else // initialize new Connection
         {
-          const auto outPolicy = _node.nodeDataModel()->portOutConnectionPolicy(portIndex);
-          if (!connections.empty() &&
-              portToCheck == PortType::Out &&
-              outPolicy == NodeDataModel::ConnectionPolicy::One)
+          if (portToCheck == PortType::Out)
           {
-            _scene.deleteConnection( *connections.begin()->second );
+            const auto outPolicy = _node.nodeDataModel()->portOutConnectionPolicy(portIndex);
+            if (!connections.empty() &&
+                outPolicy == NodeDataModel::ConnectionPolicy::One)
+            {
+              _scene.deleteConnection( *connections.begin()->second );
+            }
+
+            // todo add to FlowScene
+            auto connection = _scene.createConnection(portToCheck,
+                                                      _node,
+                                                      portIndex);
+
+            _node.nodeState().setConnection(portToCheck,
+                                            portIndex,
+                                            *connection);
+
+            connection->getConnectionGraphicsObject().grabMouse();
           }
-
-          // todo add to FlowScene
-          auto connection = _scene.createConnection(portToCheck,
-                                                    _node,
-                                                    portIndex);
-
-          _node.nodeState().setConnection(portToCheck,
-                                          portIndex,
-                                          *connection);
-
-          connection->getConnectionGraphicsObject().grabMouse();
         }
       }
     };

test/CMakeLists.txt

@@ -5,6 +5,7 @@ add_executable(test_nodes
   test_main.cpp
   src/test_dragging.cpp
   src/TestDataModelRegistry.cpp
+  src/TestNodeGraphicsObject.cpp
 )
 
 target_include_directories(test_nodes

test/src/TestNodeGraphicsObject.cpp

@@ -0,0 +1,66 @@
+#include <nodes/FlowScene>
+#include <nodes/FlowView>
+#include <nodes/Node>
+#include <nodes/NodeDataModel>
+
+#include <catch.hpp>
+
+#include <QtTest>
+
+#include "ApplicationSetup.hpp"
+#include "StubNodeDataModel.hpp"
+
+using QtNodes::FlowScene;
+using QtNodes::FlowView;
+using QtNodes::Node;
+using QtNodes::NodeDataModel;
+using QtNodes::NodeGraphicsObject;
+using QtNodes::PortType;
+
+TEST_CASE("NodeDataModel::portOutConnectionPolicy(...) isn't called for input "
+          "connections (issue #127)",
+          "[gui]")
+{
+  class MockModel : public StubNodeDataModel
+  {
+  public:
+    unsigned int nPorts(PortType) const override { return 1; }
+
+    NodeDataModel::ConnectionPolicy
+    portOutConnectionPolicy(int index) const override
+    {
+      portOutConnectionPolicyCalledCount++;
+      return NodeDataModel::ConnectionPolicy::One;
+    }
+
+    mutable int portOutConnectionPolicyCalledCount = 0;
+  };
+
+  auto setup = applicationSetup();
+
+  FlowScene scene;
+  FlowView  view(&scene);
+
+  // Ensure we have enough size to contain the node
+  view.resize(640, 480);
+
+  view.show();
+  REQUIRE(QTest::qWaitForWindowExposed(&view));
+
+  auto& node  = scene.createNode(std::make_unique<MockModel>());
+  auto& model = dynamic_cast<MockModel&>(*node.nodeDataModel());
+  auto& ngo   = node.nodeGraphicsObject();
+  auto& ngeom = node.nodeGeometry();
+
+  // Move the node to somewhere in the middle of the screen
+  ngo.setPos(QPointF(50, 50));
+
+  // Compute the on-screen position of the input port
+  QPointF scInPortPos = ngeom.portScenePosition(0, PortType::In, ngo.sceneTransform());
+  QPoint  vwInPortPos = view.mapFromScene(scInPortPos);
+
+  // Create a partial connection by clicking on the input port of the node
+  QTest::mousePress(view.windowHandle(), Qt::LeftButton, Qt::NoModifier, vwInPortPos);
+
+  CHECK(model.portOutConnectionPolicyCalledCount == 0);
+}