Improve and add assertions for random failing HoverTest #926 #1808

[HeikoKlare]

This contributes to fixing the randomly failing HoverTests:

• Removes unnecessary focus enforcing: The code checks for the text editor having focus and afterwards uses different methods to force focus to the widget's shell again. This is unnecessary and is only prone to introduce further problems.
• Introduces further assertions: in order to better locate the cause of the failing tests, assertions are added for the conditions, on which the execution waits, to be actually fulfilled.

Contributes to #926

Contributes to #1808

[github-actions]

Test Results

 1 821 files  +  307   1 821 suites  +307   1h 55m 49s ⏱️ + 20m 50s
 7 725 tests ±    0   7 497 ✅ +    2  228 💤  -   1  0 ❌  - 1 
24 336 runs  +1 846  23 589 ✅ +1 648  747 💤 +199  0 ❌  - 1 

Results for commit ba6a578. ± Comparison against base commit 10d96b5.

♻️ This comment has been updated with latest results.

[HeikoKlare]

With these changes, the test randomly fails as follows:

hover data not found
java.lang.AssertionError: hover data not found
	at org.junit.Assert.fail(Assert.java:89)
	at org.junit.Assert.assertTrue(Assert.java:42)
	at org.eclipse.ui.genericeditor.tests.HoverTest.triggerCompletionAndRetrieveInformationControlManager(HoverTest.java:259)
	at org.eclipse.ui.genericeditor.tests.HoverTest.testEnabledWhenHover(HoverTest.java:97)

[Wittmaxi]

In general, I have seen SWT tests fail because some control wasn't in focus (happens in the FInd/Replace tests if you click into the window while something is being tested, for example). I think these assertions can at least notify us if something like that is happenign and help us further diagnose what is happening.