Tl;Dr at the end

So I'm in the transportation industry formerly a mechanic on tractor trailers.

Every year leading up to winter we'd do a battery test to make sure the batteries aren't getting weak and will leave the driver stranded. It's not terribly in depth just pull the battery cables off, wipe the dirt and road grime off, hookup the tester and test, then hookup the batteries again after the test. Well this particular night I had 2 new guys shadowing me and I taught them how to properly do this test. I didn't take the cables 100% apart because doing so would've broken them.

Clean the batteries and test successfully and put the truck back together. Manager comes over like 30 minutes later saying I didn't do the test at all. Says the batteries are dirty and I lied and faked the results. Even though i had 2 new guys say otherwise. Had me come in the office to get written up and told to do it again since truck had to go back at close of business.

Took everything apart 110% by the book. Broke a few battery cables and surprise surprise we don't have the parts to replace them so truck is stuck at the shop when it should go back and he gets chewed out and made to do more work to find a replacement.

Tl;Dr Boss wrote me up saying I lied and didn't do the work, I did it again to his standards which broke things and created more work and headache for him