Improve rcl clock test coverage.

Signed-off-by: Michel Hidalgo <michel@ekumenlabs.com>

rcl/src/rcl/time.c

@@ -171,11 +171,8 @@ rcl_ros_clock_fini(
     return RCL_RET_ERROR;
   }
   rcl_clock_generic_fini(clock);
-  if (!clock->data) {
-    RCL_SET_ERROR_MSG("clock data invalid");
-    return RCL_RET_ERROR;
-  }
-  clock->allocator.deallocate((rcl_ros_clock_storage_t *)clock->data, clock->allocator.state);
+  clock->allocator.deallocate(clock->data, clock->allocator.state);
+  clock->data = NULL;
   return RCL_RET_OK;
 }
 
@@ -366,6 +363,10 @@ rcl_set_ros_time_override(
   }
   rcl_time_jump_t time_jump;
   rcl_ros_clock_storage_t * storage = (rcl_ros_clock_storage_t *)clock->data;
+  if (!storage) {
+    RCL_SET_ERROR_MSG("Clock storage is not initialized, cannot enable override.");
+    return RCL_RET_ERROR;
+  }
   if (storage->active) {
     time_jump.clock_change = RCL_ROS_TIME_NO_CHANGE;
     rcl_time_point_value_t current_time;
@@ -453,19 +454,18 @@ rcl_clock_remove_jump_callback(
   }
 
   // Shrink size of the callback array
-  if (clock->num_jump_callbacks == 1) {
+  if (clock->num_jump_callbacks-- == 1) {
     clock->allocator.deallocate(clock->jump_callbacks, clock->allocator.state);
     clock->jump_callbacks = NULL;
   } else {
     rcl_jump_callback_info_t * callbacks = clock->allocator.reallocate(
-      clock->jump_callbacks, sizeof(rcl_jump_callback_info_t) * (clock->num_jump_callbacks - 1),
+      clock->jump_callbacks, sizeof(rcl_jump_callback_info_t) * clock->num_jump_callbacks,
       clock->allocator.state);
     if (NULL == callbacks) {
       RCL_SET_ERROR_MSG("Failed to shrink jump callbacks");
       return RCL_RET_BAD_ALLOC;
     }
     clock->jump_callbacks = callbacks;
   }
-  --(clock->num_jump_callbacks);
   return RCL_RET_OK;
 }