core, integration_tests: Address review commets mavlink#310

1. Make `camera_id` to start from 0.
2. Minor changes to multi-comp integration test.

core/mavlink_system.cpp

@@ -353,12 +353,12 @@ bool MAVLinkSystem::is_camera(uint8_t comp_id)
            && (comp_id <= MAV_COMP_ID_CAMERA6);
 }
 
-bool MAVLinkSystem::has_camera(uint8_t camera_id) const
+bool MAVLinkSystem::has_camera(int camera_id) const
 {
-    uint8_t camera_comp_id = (camera_id == 0) ?
-                             camera_id : (MAV_COMP_ID_CAMERA + (camera_id - 1));
+    int camera_comp_id = (camera_id == -1) ?
+                         camera_id : (MAV_COMP_ID_CAMERA + camera_id);
 
-    if (camera_comp_id == 0) { // Check whether the system has any camera.
+    if (camera_comp_id == -1) { // Check whether the system has any camera.
         for (auto compid : _components) {
             if (is_camera(compid)) {
                 return true;

core/mavlink_system.h

@@ -104,7 +104,7 @@ class MAVLinkSystem
 
     bool is_standalone() const;
     bool has_autopilot() const;
-    bool has_camera(uint8_t camera_id = 0) const;
+    bool has_camera(int camera_id = -1) const;
     bool has_gimbal() const;
 
     uint64_t get_uuid() const;

core/system.cpp

@@ -38,7 +38,7 @@ bool System::has_autopilot() const
     return _mavlink_system->has_autopilot();
 }
 
-bool System::has_camera(uint8_t camera_id) const
+bool System::has_camera(int camera_id) const
 {
     return _mavlink_system->has_camera(camera_id);
 }

core/system.h

@@ -35,13 +35,13 @@ class System
     /**
      * @brief Checks whether the system has a camera with the given camera ID.
      *
-     * A System may have several cameras with ID starting from 1.
+     * A System may have several cameras with ID starting from 0.
      * When called without passing camera ID, it checks whether the system has
      * any camera.
-     * @param camera_id ID of the camera starting from 1 onwards.
+     * @param camera_id ID of the camera starting from 0 onwards.
      * @return true if camera with the given camera ID is found, false otherwise.
      */
-    bool has_camera(uint8_t camera_id = 0) const;
+    bool has_camera(int camera_id = -1) const;
 
     /**
      * @brief Checks whether the system has a gimbal.

integration_tests/multi_components.cpp

@@ -48,11 +48,11 @@ TEST_F(SitlTest, MultiComponentDiscovery)
         auto has_gimbal = system.has_gimbal();
 
         if (has_autopilot && has_camera && !has_gimbal) {
-            std::cout << "Its an Autopilot with a Camera." << '\n';
+            std::cout << "Its an autopilot with camera(s)." << '\n';
         } else if (is_standalone && has_camera) {
-            std::cout << "Its a Standalone camera." << '\n';
+            std::cout << "Its a standalone camera." << '\n';
         } else if (has_autopilot && !has_camera) {
-            std::cout << "Its an Autopilot alone." << '\n';
+            std::cout << "Its an autopilot alone." << '\n';
         }
     }
 }