Make test packages into separate modules

[mx-psi]

Similar to what we did in the case of consumertest (see #10692), we can turn the exportertest, receivertest, extensiontest, processortest and connectortest packages into modules.

• Make exportertest into its own module #11461
• Make receivertest into its own module #11462
• Make extensiontest into its own module #11463
• Make componenttest into its own module #11464
• Make authtest into its own module #11465
• Make processortest into its own module #11218
• Make connectortest into its own module #11460

[wildum]

I can help with this one, I can start with the processortest pkg

[mx-psi]

Thanks! I opened a subissue for processortest

[wildum]

I also did it for the connectortest pkg: #11228

For the processor, receiver and exporter it's a bit more complicated because the helper pkgs don't have their own modules which creates cyclic dependencies as explained in #11218 (the processortest pkg should depend on the processor pkg but the processor pkg should not depend on the processortest pkg)

I can do it for all packages. Because all of them are very similar, I will wait for one PR (either connector or processor) to me reviewed before moving forward with the others @mx-psi

[bogdandrutu]

@mx-psi doesn't this cause lots of duplicate code, since we cannot use the test package in the main package because of circular deps? E.g. you cannot use processortest in the processor package for testing reasons.

[mx-psi]

@bogdandrutu This causes zero duplicate code. You can use processortest in the processor package; there are no cycles between Go modules, only cycles between Go packages, so this does not improve or worsen cycles