InputDestination.send is sending more than 1 message in version 5.0.0

[jenthomas88]

Describe the issue
We are migrating our microservices from Spring boot 3 to Spring boot 4 (and so Spring cloud 2025.1.0). This migration is making several of our integration tests fail and all relevant tests contain InputDestination.send
We were able to isolate the problem in the attached demo project

To Reproduce
You need at least 2 test classes with inputDestination.send in the same test execution
Just do a gradle test on the attached demo project
You will see that the 1st class to execute is ok but the second will send 2 messages instead of 1 (and the 3rd class to execute will send 3...)

Version of the framework
Spring boot 4.0.1
Spring cloud 2025.1.0
Spring cloud stream 5.0.0
Spring cloud stream test binder 5.0.0

Demo project
demo.zip

[Swierkowski]

I see the same issue.

For every test class, spring lifecycle start method is called and the new instance of the same MessageHandler is registered again.

So the message is sent once, but it is handled many times.