Add Assertion to the SharedTimerTest

[Codegass]

Resolve #2357

Is your feature request related to a problem? If so, please give a short summary of the problem and how the feature would resolve it

When I am walking through the unit test of the mssql-jdbc, I noticed that currently the SharedTimerTest does not contain any assertion statement to verify the behavior and state of the SharedTimer after execution of its getTimer() method in a multithreaded environment. The test ensures that references are added and removed, but does not assert the expected state of the SharedTimer (e.g., it is stopped and cleaned up properly after all references are removed). This could potentially mask issues with how SharedTimer manages its lifecycle and resources.

Current Implementation:

@Test
    void getTimer() throws InterruptedException, ExecutionException, TimeoutException {
        final int iterations = 500;

        ExecutorService executor = Executors.newFixedThreadPool(2);
        try {
            ArrayList<CompletableFuture<?>> futures = new ArrayList<>(iterations);
            for (int i = 0; i < iterations; i++) {
                futures.add(CompletableFuture.runAsync(() -> SharedTimer.getTimer().removeRef(), executor));
            }

            CompletableFuture.allOf(futures.toArray(new CompletableFuture[0])).get(2, TimeUnit.MINUTES);
        } finally {
            executor.shutdown();
        }
    }

Describe the preferred solution

I'd like to propose a minor improvement by adding a simple assertion at the end of the getTimer test method to verify that the SharedTimer has indeed been stopped and its resources have been cleaned up after all references to it have been removed. This could be accomplished by asserting that SharedTimer.isRunning() returns false, indicating that the internal ScheduledThreadPoolExecutor has been shut down and the SharedTimer instance has been cleaned up. Here is the suggested code snippet for this improvement:

    @Test
    void getTimer() throws InterruptedException, ExecutionException, TimeoutException {
        final int iterations = 500;
        ExecutorService executor = Executors.newFixedThreadPool(2);

        try {
            ArrayList<CompletableFuture<?>> futures = new ArrayList<>(iterations);
            for (int i = 0; i < iterations; i++) {
                futures.add(CompletableFuture.runAsync(() -> SharedTimer.getTimer().removeRef(), executor));
            }

            CompletableFuture.allOf(futures.toArray(new CompletableFuture[0])).get(2, TimeUnit.MINUTES);
        } finally {
            executor.shutdown();
            if (!executor.awaitTermination(800, TimeUnit.MILLISECONDS)) {
                executor.shutdownNow();
            }
        }

        assertFalse(SharedTimer.isRunning(), "SharedTimer should be stopped after all references are removed.");
    }

Describe alternatives you've considered

An alternative would be to incorporate more detailed logging within the SharedTimer class regarding its state transitions (e.g., when references are added or removed, and when it starts or stops). While this would provide more insight during test execution, it would not replace the need for explicit assertions to verify the correct behavior programmatically.

Reference Documentations/Specifications

This suggestion does not directly relate to any specific JDBC Specifications.

[codecov]

Codecov Report

Attention: Patch coverage is 67.02703% with 61 lines in your changes are missing coverage. Please review.

Project coverage is 50.21%. Comparing base (9a8849b) to head (c3894d1).
Report is 24 commits behind head on main.

❗ Current head c3894d1 differs from pull request most recent head 24944b8. Consider uploading reports for the commit 24944b8 to get more accurate results

Files	Patch %	Lines
...a/com/microsoft/sqlserver/jdbc/SQLServerError.java	32.14%	17 Missing and 2 partials ⚠️
...microsoft/sqlserver/jdbc/SQLServerInfoMessage.java	44.44%	14 Missing and 1 partial ⚠️
...m/microsoft/sqlserver/jdbc/SQLServerException.java	64.28%	5 Missing ⚠️
...in/java/com/microsoft/sqlserver/jdbc/IOBuffer.java	50.00%	3 Missing and 1 partial ⚠️
...oft/sqlserver/jdbc/SQLServerBulkCSVFileRecord.java	80.00%	3 Missing and 1 partial ⚠️
.../microsoft/sqlserver/jdbc/SQLServerConnection.java	84.00%	3 Missing and 1 partial ⚠️
...m/microsoft/sqlserver/jdbc/SQLServerStatement.java	73.33%	2 Missing and 2 partials ⚠️
...rc/main/java/com/microsoft/sqlserver/jdbc/dtv.java	33.33%	1 Missing and 1 partial ⚠️
...t/sqlserver/jdbc/SQLServerConnectionPoolProxy.java	50.00%	1 Missing ⚠️
...oft/sqlserver/jdbc/SQLServerPreparedStatement.java	87.50%	0 Missing and 1 partial ⚠️
... and 2 more

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2381      +/-   ##
============================================
+ Coverage     50.03%   50.21%   +0.18%     
- Complexity     3785     3842      +57     
============================================
  Files           143      145       +2     
  Lines         33204    33360     +156     
  Branches       5629     5654      +25     
============================================
+ Hits          16613    16752     +139     
- Misses        14207    14210       +3     
- Partials       2384     2398      +14     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[lilgreenbird]

please update as per review comments

Addressed