The Target company I am familiar with does not work in well testing. The advert link posted by NgamiaSwede is for a well test engineer on month rotation. The well test engineer will normally be employed by the oil company operating the well (Tullow). As Tullow has an extensive testing program they will need two test engineers working back to back. Their job is to plan / organise / execute the well testing program in order to meet the oil company objectives, primarily obtain the necessary reservoir and flow data to allow reserves / potential commerciality etc. to be assessed. The well testing equipment will be provided by a third party service contractor such as Schlumberger / Expro / Weatherford etc. The well test engineer (with the drilling rig supervisor) will manage this third party equipment and personnel to ensure the well testing is undertaken safely, economically and achieves the set objectives. It would be normal for the company well test engineer to check equipment at the port of entry to ensure it is the correct equipment and in good working order - before it is trucked to the well site.
All this said, I am not familiar with a company with the name of Target which undertakes well testing. But I retired from the industry a couple of years ago so I am not current.