Fixing pekko test: revert previous change and fix test server (#9530)

* Revert "add waiting hook in HttpServerTest to try to solve Pekko's flakiness (#9493)"

This reverts commit 4644198.

* close span on exception handling in pekko test server

Author: vandonr

dd-java-agent/instrumentation-testing/src/main/groovy/datadog/trace/agent/test/base/HttpServerTest.groovy

@@ -174,15 +174,6 @@ abstract class HttpServerTest<SERVER> extends WithHttpServer<SERVER> {
     }
   }
 
-  /**
-   * Hook method to allow subclasses to wait for request processing to complete.
-   * This is particularly useful for asynchronous HTTP server implementations
-   * where spans may still not be closed after the HTTP response is sent.
-   */
-  protected void waitForRequestToComplete() {
-    // Default implementation does nothing - override in subclasses as needed
-  }
-
   // used in blocking tests to check if the handler was skipped
   volatile boolean handlerRan
 
@@ -1204,8 +1195,6 @@ abstract class HttpServerTest<SERVER> extends WithHttpServer<SERVER> {
       TEST_DATA_STREAMS_WRITER.waitForGroups(1)
     }
 
-    waitForRequestToComplete()
-
     expect:
     response.code() == EXCEPTION.status
     if (testExceptionBody()) {

dd-java-agent/instrumentation/pekko-http-1.0/src/baseTest/groovy/PekkoHttpServerInstrumentationTest.groovy

@@ -40,21 +40,6 @@ abstract class PekkoHttpServerInstrumentationTest extends HttpServerTest<PekkoHt
     true
   }
 
-  @Override
-  protected void waitForRequestToComplete() {
-    // Pekko HTTP is asynchronous, and spans may not be completed
-    // immediately after the HTTP response is sent. Wait for the trace
-    // to be written to avoid race conditions in trace assertions.
-    try {
-      // Wait up to 1 sec for the trace to be written
-      TEST_WRITER.waitForTracesMax(1, 1)
-    } catch (InterruptedException e) {
-      Thread.currentThread().interrupt()
-      // If interrupted, proceed anyway - test may still pass
-    }
-  }
-
-
   //@Ignore("https://github.com/DataDog/dd-trace-java/pull/5213")
   @Override
   boolean testBadUrl() {

dd-java-agent/instrumentation/pekko-http-1.0/src/baseTest/scala/PekkoHttpTestWebServer.scala

@@ -136,7 +136,11 @@ object PekkoHttpTestWebServer {
   private val exceptionHandler = ExceptionHandler {
     case e: Exception =>
       val span = activeSpan()
-      TraceUtils.handleException(span, e)
+      if (span != null) {
+        // The exception handler is bypassing the normal instrumentation flow, so we need to handle things here
+        TraceUtils.handleException(span, e)
+        span.finish()
+      }
       complete(
         HttpResponse(status = EXCEPTION.getStatus, entity = e.getMessage)
       )