What exactly does it look like when a rope with different terminations is stretched until it breaks?
Two basic types of terminals were used in the test:
1) Loops around a smooth small diameter log.
2) Thimble with Fist-Grip, knots and securing Bull-Dog Grip.
When testing the strength of the rope in the laboratory, either the rope is wrapped with several turns around a large diameter cylinder or the rope is fixed in special jaws (where the fibres in the rope barely bend at all).
See the test in video: Mastrant tests: Breaking strength of different terminations (Premium rope 12 mm - 1/2") (youtube.com) (with details in description).