Intermingled with a test's set-up of the data and objects it depends on are assertions which attempt to ensure that set-up was successful. The net effect of this often resembles a "Arrange-Assert-Act-Assert" pattern.
It may be the case that the original author isn't quite sure that the code the subject depends on actually works. If that's the case, maybe it's not itself well-tested, or is perhaps highly-variable depending on broader environmental issues.
In either case, the best course of action would be to directly increase one's confidence in those depended-on units, rather than adding prophylactic assertions to an unrelated test. Either add the tests needed to increase one's confidence in said units' behavior, or improve their implementations to act more consistently in the face of changing environmental conditions.
It's easy to fall into a trap that says all assertions are inherently good—what's the harm, after all, in making sure that a bit of code works? Well, as seen in 7-Layer-Testing, unnecessary assertions can result in significantly reduced productivity for teams when the code being asserted is changed.
Acknowledging the cost of an assertion as being more than its runtime penalty (which is often imperceptibly small), but instead a factor of its coupling to the behavior being asserted, suggests that assertions of a test's arrangements are typically not appropriate and can be safely deleted. If the arrangement fails, one should be able to safely presume (if that upstream behavior were actually necessary) that the ultimate behavior under test would fail as well.
This test features several rounds of premature assertions making sure that the subject's dependencies are configured appropriately before continuing.
Consider the design of the subject & its dependencies. Is there a good reason why the original author might have added the premature assertions? If so, what else could be done to mitigate that concerns?
Regardless, those premature assertions should ultimately be eliminated. Is there any other change that should be made to the design to discourage the impulse that added them in the first place?