chore: simplify TrackedEntityService.getTrackedEntity(UID, ...) logic DHIS2-18541

[teleivo]

This change is necessary for #19377 and should make changes in behavior easier to see/discuss.

We have two methods for getting a single TE. They were implemented independently with convoluted logic. Let one reuse the other. Separate fetching, ACL, mapping to make the flow easier to follow. Move the TETAV logic in one place. This is the only way we can ensure the behavior is the same across different code paths.

Add an assertContainsOnly variant that lets us map both collection before making the actual assertion. This makes the assertion error easier to read.

assertContainsOnly(
    Set.of(tetavA, tetavB),
    trackedEntity.getTrackedEntityAttributeValues(),
    TrackedEntityAttributeValue::getValue);

gives you

org.opentest4j.AssertionFailedError: Expected [C] NOT to be in [A, B, C] ==> 
Expected :true
Actual   :false

instead of a giant output with most fields being equal and or irrelevant.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud