Getting RLException: [tello_node.launch] is neither a launch file in package [tello_driver] nor is [tello_driver] a launch file name despite rospack find working

edit

Hi,

I've just been using ROS melodic for the first time on Ubuntu 18.04.6 LTS, having completed the first few tutorials successfully I've been attempting to get this tello_driver working.

Having followed the instructions on the git repository, I've unfortunately been running into an error when trying to use roslaunch. After cloning the repository into my catkin_ws/src directory, I've ran the following commands:

lewis@lewis-ThinkPad-L480:~/ROS_tello/catkin_ws$ catkin build
-------------------------------------------------------------------------
Profile:                     default
Extending:             [env] /home/lewis/catkin_ws/devel:/opt/ros/melodic
Workspace:                   /home/lewis/ROS_tello/catkin_ws
-------------------------------------------------------------------------
Build Space:        [exists] /home/lewis/ROS_tello/catkin_ws/build
Devel Space:        [exists] /home/lewis/ROS_tello/catkin_ws/devel
Install Space:      [unused] /home/lewis/ROS_tello/catkin_ws/install
Log Space:         [missing] /home/lewis/ROS_tello/catkin_ws/logs
Source Space:       [exists] /home/lewis/ROS_tello/catkin_ws/src
DESTDIR:            [unused] None
-------------------------------------------------------------------------
Devel Space Layout:          linked
Install Space Layout:        None
-------------------------------------------------------------------------
Additional CMake Args:       None
Additional Make Args:        None
Additional catkin Make Args: None
Internal Make Job Server:    True
Cache Job Environments:      False
-------------------------------------------------------------------------
Whitelisted Packages:        None
Blacklisted Packages:        None
-------------------------------------------------------------------------
Workspace configuration appears valid.

NOTE: Forcing CMake to run for each package.
-------------------------------------------------------------------------
[build] Found '1' packages in 0.0 seconds.                                                              
[build] Updating package table.                                                                         
Starting  >>> catkin_tools_prebuild                                                                     
Finished  <<< catkin_tools_prebuild                [ 1.8 seconds ]                                      
Starting  >>> tello_driver                                                                              
Finished  <<< tello_driver                         [ 3.6 seconds ]                                      
[build] Summary: All 2 packages succeeded!                                                              
[build]   Ignored:   None.                                                                              
[build]   Warnings:  None.                                                                              
[build]   Abandoned: None.                                                                              
[build]   Failed:    None.                                                                              
[build] Runtime: 5.4 seconds total.                                                                     
[build] Note: Workspace packages have changed, please re-source setup files to use them.
lewis@lewis-ThinkPad-L480:~/ROS_tello/catkin_ws$ source devel/setup.bash
lewis@lewis-ThinkPad-L480:~/ROS_tello/catkin_ws$ rospack find tello_driver 
/home/lewis/ROS_tello/catkin_ws/src/tello_driver
lewis@lewis-ThinkPad-L480:~/ROS_tello/catkin_ws$ roslaunch tello_driver tello_node.launch
RLException: [tello_node.launch] is neither a launch file in package [tello_driver] nor is [tello_driver] a launch file name
The traceback for the exception was written to the log file

Any suggestions on how to fix this would be great, as I don't fully understand why rospack find tello_driver works correctly, but then roslaunch appears unable to find the tello_driver.

Here are my environment variables (if that helps):

lewis@lewis-ThinkPad-L480:~/.ros/log$ env | grep ROS
OLDPWD=/home/lewis/ROS_tello/catkin_ws
ROS_ETC_DIR=/opt/ros/melodic/etc/ros
ROS_ROOT=/opt/ros/melodic/share/ros
ROS_MASTER_URI=http://localhost:11311
ROS_VERSION=1
ROS_PYTHON_VERSION=2
ROS_PACKAGE_PATH=/home/lewis/catkin_ws/src:/opt/ros/melodic/share
ROSLISP_PACKAGE_DIRECTORIES=/home/lewis/catkin_ws/devel/share/common-lisp
ROS_DISTRO=melodic

If any other information is needed to figure this out, please let me know.

Apologies if I'm missing something small, but between the ROS tutorials and other posts about this kinda of issue on here (most being fixed by ensuring the source has been set using source devel/setup.bash) I've been unable to make progress.

Thanks in advanced for any help.