GH-3840: Migrate Redis tests to Testcontainers

[oxcafedead]

Fixes #3840

• Create a new abstraction RedisTest for Testcontainers-based tests
• Move existing common utility methods to the new interface
• Migrate all existing Redis tests to use this new RedisTest interface
• Migrate all existing Redis tests to JUnit5
• Make all existing Redis tests confirming to JUnit5 standards, such as
  default methods and classes visibility instead of public
• Add a dependency for parametrized tests in JUnit5
• Improve assertions readability across tests, for instance:
  assertThat(thing.size()).isEqualTo(2) -> assertThat(thing).hasSize(2)
• Add real assertions to
  RedisLockRegistryTests.twoRedisLockRegistryTest (earlier it did not
  have assertions at all)
• Reformat, rearrange and cleanup the code

[oxcafedead]

Sorry for many changes to review, but I decided that is would be better that 'chunk-based' approach.
Just for the note, locally I've run :spring-integration-redis:testAll and :spring-integration-file:testAll to verify the migration.

[oxcafedead]

I also noticed that no JUnit5 tests follow the recommendation from JUnit to use default classes/methods visibility:
https://junit.org/junit5/docs/current/user-guide/#writing-tests-classes-and-methods

It is generally recommended to omit the public modifier for test classes, test methods, and lifecycle methods unless there is a technical reason for doing so – for example, when a test class is extended by a test class in another package. Another technical reason for making classes and methods public is to simplify testing on the module path when using the Java Module System.

I removed public for redis tests by inertia, however if this is some sort of convention for the project I can revert this change.

UPD
Actually some tests do follow default visibility (at least for methods), so probably is is OK. Ignore this comment 😄

[artembilan]

Hi @oxcafedead !

Thank you for your thorough contribution as usual!

Re. public on test method.
Previously all our tests were on JUnit 4, where public is required.
We migrate to JUnit 5 gradually, when we touch the test.

It is really some burden to remove all those public in the class and does not look like leaving it cause some harm.

And from the JUnit doc you've mentioned:

Test classes, test methods, and lifecycle methods are not required to be public, but they must not be private.

So, doesn't look like there is a strong requirement to do that extra work removing the public modifier.

Therefore there is no any convention from our side how to be with such a migration.
First of all it is just about tests, so the code might not be ideal.
Secondly, it is better to be reasonable what you do, but don't waste your time for something what is not painful like this public modifier removal.

[artembilan]

Just a couple nit-picks.

Otherwise this is great work, @oxcafedead , as usual!

[artembilan]

LGTM.

Pulling locally for final verification and merging...

[artembilan]

Merged as 1c461a3 after some minor compatibility fix.

@oxcafedead ,

thank you again.