sometimes we have several assertions with the same condition in the same test
at different stages, and when these fail (the ones that print the condition
text) you don't know which one it was. other assertions didn't print the
condition text (variable names), just the expected and unexpected values.
So now, all assertions print context line, and conditin text.
besides, one of the major differences between 'assert' and 'assert_equal',
is that the later is able to print the value that doesn't match the expected.
if there is a rare non-reproducible failure, it is helpful to know what was
the value the test encountered and how far it was from the threshold.
So now, adding assert_lessthan and assert_range that can be used in some places.
were we used just 'assert { a > b }' so far.
Some commands would want to open a key without touching it's LRU/LFU
similarly to the OBJECT or DEBUG command do.
Other commands may want to implement logic similar to what RESTORE
does (and in the future MIGRATE) and get/set the LRU or LFU.
Adding a test for coverage for RM_Call in a new "misc" unit
to be used for various short simple tests
also solves compilation warnings in redismodule.h and fork.c
As we know if a module exports module-side data types,
unload it is not allowed. This rule is the same with
blocked clients in module, because we use background
threads to implement module blocked clients, and it's
not safe to unload a module if there are background
threads running. So it's necessary to check if any
blocked clients running in this module when unload it.
Moreover, after that we can ensure that if no modules,
then no module blocked clients even module unloaded.
So, we can call moduleHandleBlockedClients only when
we have installed modules.
Calling a module hook callback may result in callback operations in turn
triggering other events the module is subscribed too. We don't want to
trigger those, it's unsafe and quite confusing, and to do it correcly we
would need to maintain an event list: quite a more complex
implementation.
