add missing helper test class

Signed-off-by: Ashton Larkin <ashton@openrobotics.org>

src/plugins/world_control/CMakeLists.txt

@@ -1,6 +1,7 @@
 ign_gui_add_plugin(WorldControl
   SOURCES
     WorldControl.cc
+    WorldControlEventListener.cc
   QT_HEADERS
     WorldControl.hh
     WorldControlEventListener.hh

src/plugins/world_control/WorldControlEventListener.cc

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2021 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+*/
+
+#include "WorldControlEventListener.hh"
+
+using namespace ignition;
+using namespace gui;
+
+WorldControlEventListener::WorldControlEventListener()
+{
+  ignition::gui::App()->findChild<
+    ignition::gui::MainWindow *>()->installEventFilter(this);
+}
+
+WorldControlEventListener::~WorldControlEventListener() = default;
+
+bool WorldControlEventListener::eventFilter(QObject *_obj, QEvent *_event)
+{
+  if (_event->type() == ignition::gui::events::WorldControl::kType)
+  {
+    auto worldControlEvent =
+      reinterpret_cast<gui::events::WorldControl *>(_event);
+    if (worldControlEvent)
+    {
+      this->listenedToPlay = !worldControlEvent->WorldControlInfo().pause();
+      this->listenedToPause = worldControlEvent->WorldControlInfo().pause();
+      this->listenedToStep =
+        worldControlEvent->WorldControlInfo().multi_step() > 0u;
+    }
+  }
+
+  // Standard event processing
+  return QObject::eventFilter(_obj, _event);
+}

src/plugins/world_control/WorldControlEventListener.hh

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2021 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+*/
+#ifndef IGNITION_GUI_WORLDCONTROLEVENTLISTENER_HH_
+#define IGNITION_GUI_WORLDCONTROLEVENTLISTENER_HH_
+
+#include "ignition/gui/Application.hh"
+#include "ignition/gui/Export.hh"
+#include "ignition/gui/GuiEvents.hh"
+#include "ignition/gui/MainWindow.hh"
+#include "ignition/gui/qt.h"
+
+namespace ignition
+{
+namespace gui
+{
+  /// \brief Helper class for testing listening to events emitted by the
+  /// WorldControl plugin. This is used for testing the event behavior of
+  /// the WorldControl plugin.
+  class IGNITION_GUI_VISIBLE WorldControlEventListener : public QObject
+  {
+    Q_OBJECT
+
+    /// \brief Constructor
+    public: WorldControlEventListener();
+
+    /// \brief Destructor
+    public: virtual ~WorldControlEventListener() override;
+
+    // Documentation inherited
+    protected: bool eventFilter(QObject *_obj, QEvent *_event) override;
+
+    /// \brief Whether a play event has been received (true) or not (false)
+    public: bool listenedToPlay{false};
+
+    /// \brief Whether a pause event has been received (true) or not (false)
+    public: bool listenedToPause{false};
+
+    /// \brief Whether a pause event has been received (true) or not (false)
+    public: bool listenedToStep{false};
+  };
+}
+}
+
+#endif