Tests effectively freeze requirements; you should test those things which should be preserved throughout any changes, and not test those things which should be

Tests effectively freeze requirements; you should test those things which should be preserved throughout any changes, and not test those things which should be open to change. In this case, it seems that is no real requirements for any of these 9 steps - perhaps the implementer could figure out how to do the same outcome by skipping a step or merging two steps, and the existence of unit tests for these 9 functions somehow encodes the idea that these 9 functions each are inherently needed, which is not necessarily true.