Development: Fix flaky IrisMessageIntegrationTest

[laadvo]

Checklist

General

• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

Server

• I followed the coding and design guidelines.
• I documented the Java code using JavaDoc style.

Motivation and Context

The test IrisMessageIntegrationTest.sendOneMessage is flaky with H2 on Bamboo and Github Actions. It sometimes fails with

org.mockito.exceptions.verification.NoInteractionsWanted: 
      No interactions wanted here:
       -> at de.tum.in.www1.artemis.iris.AbstractIrisIntegrationTest.verifyNothingElseWasSentOverWebsocket(AbstractIrisIntegrationTest.java:162)

This is due to the test sendTwoMessages(), which is run before sendOneMessage() sends 4 messages in asynch.
These count as unverified interractions with the mock and sometimes happen exactly when no interractions are wanted, causing verifyNoMoreInteractions(websocketMessagingService) to fail.
Additionally, we have some tests related to group notifications and when the release or assessament due date of an exercise is reached, a notification is sent. This can occur while sendOneMessage is run, resulting in unverified interractions with the same mock.

Description

This PR adds a verify statement at the end of sendTwoMessages(), making sure that the websocketMessagingService.sendMessageToUser calls do no affect the test sendOneMessage() which comes after it. In addition, it removes the verifyNoMoreInteractions statements from tests, so that they do not fail in case an asynch notification is sent while they are run.

Review Progress

Code Review

• Code Review 1
• Code Review 2

Test Coverage

unchanged

[DominikRemo]

Changes LGTM, thanks for the fix 🚀