fix: setMaxConnections uses func arg in comparison

[dozyio]

Description

Compare against the func arg before throwing

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works

[tabcat]

Let's add a test.

[tabcat]

good catch