Are there any automated test suites for MOS 6520, 6522 and 6526 chips? I am looking for test suites aimed at making sure datasheet-based independent reimplementations of the above chips (e.g. FPGAs or emulators) work exactly as the real chips.
Klaus Dorman's functional tests for the 6502 are fantastic: https://github.com/Klaus2m5/6502_65C02_functional_tests
I am unaware of any formalised test suite for either the 6520 or 6522.
The 6526 is at least partially covered by Wolfgang Lorenz's C64 test suite. Because of the applicability to other machines, you usually see it documented for its 6502 tests (and the outward link to the suite itself there is broken; instead try that listed here) but it includes a scattering of CIA (i.e. 6526) tests:
Programs CIA1TB123 and CIA2TB123 - CIA timer B 1-3 cycles after writing CRB
Programs CIA1TA to CIA2TB - CIA timers in sysclock mode