without this change we have no option to pass the ObservationRegistry that is registered in the given TestContext's ApplicationContext as the one that should be used by the ObservationThreadLocalAccessor.

with this change we create a TestExecutionListener that will set an ObservationRegistry registered in the TestContext's ApplicationContext for each test class and after each test class will restore the previously stored ObservationRegistry instance

…ervation/ObservationThreadLocalTestListener.java

Co-authored-by: Sam Brannen <sam@sambrannen.com>

…ervation/ObservationThreadLocalTestListener.java

Co-authored-by: Sam Brannen <sam@sambrannen.com>

…ervation/ObservationThreadLocalTestListener.java

Co-authored-by: Sam Brannen <sam@sambrannen.com>

…ervation/package-info.java

Co-authored-by: Sam Brannen <sam@sambrannen.com>

…ervation/ObservationThreadLocalTestListenerTests.java

Co-authored-by: Sam Brannen <sam@sambrannen.com>

- dependencies ordered alphabetically
- renamed the test execution listener to contain "execution" and "micrometer" in the name
- production code lines are smaller (up to 100 chars)
- test execution attribute is a private static final field
- added javadocs in the test execution listener