1. Add comment for baggage test

2. Assert response status
3. Specify the key used by baggage

Author: xiepuhuan

conventions/src/main/kotlin/io.opentelemetry.instrumentation.javaagent-testing.gradle.kts

@@ -94,7 +94,7 @@ class JavaagentTestArgumentsProvider(
     "-Dio.opentelemetry.javaagent.slf4j.simpleLogger.log.io.grpc.internal.ManagedChannelImplBuilder=INFO",
     "-Dio.opentelemetry.javaagent.slf4j.simpleLogger.log.io.perfmark.PerfMark=INFO",
     "-Dio.opentelemetry.javaagent.slf4j.simpleLogger.log.io.grpc.Context=INFO",
-    "-Dotel.java.experimental.span-attributes.copy-from-baggage.include=*"
+    "-Dotel.java.experimental.span-attributes.copy-from-baggage.include=test-baggage-key-1,test-baggage-key-2"
   )
 }
 

testing-common/src/main/java/io/opentelemetry/instrumentation/testing/LibraryTestRunner.java

@@ -5,6 +5,8 @@
 
 package io.opentelemetry.instrumentation.testing;
 
+import static java.util.Arrays.asList;
+
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.baggage.propagation.W3CBaggagePropagator;
@@ -76,7 +78,11 @@ public final class LibraryTestRunner extends InstrumentationTestRunner {
                     .addSpanProcessor(new FlushTrackingSpanProcessor())
                     .addSpanProcessor(SimpleSpanProcessor.create(LoggingSpanExporter.create()))
                     .addSpanProcessor(SimpleSpanProcessor.create(testSpanExporter))
-                    .addSpanProcessor(BaggageSpanProcessor.allowAllBaggageKeys())
+                    .addSpanProcessor(
+                        new BaggageSpanProcessor(
+                            baggageKey ->
+                                asList("test-baggage-key-1", "test-baggage-key-2")
+                                    .contains(baggageKey)))
                     .build())
             .setMeterProvider(SdkMeterProvider.builder().registerMetricReader(metricReader).build())
             .setLoggerProvider(

testing-common/src/main/java/io/opentelemetry/instrumentation/testing/junit/http/AbstractHttpServerTest.java

@@ -549,9 +549,13 @@ void extractSingleBaggage() {
     AggregatedHttpRequest request =
         AggregatedHttpRequest.of(
             request(SUCCESS, method).headers().toBuilder()
+                // adding baggage header in w3c baggage format
                 .set("baggage", "test-baggage-key-1=test-baggage-value-1")
                 .build());
-    client.execute(request).aggregate().join();
+    AggregatedHttpResponse response = client.execute(request).aggregate().join();
+
+    assertThat(response.status().code()).isEqualTo(SUCCESS.getStatus());
+    assertThat(response.contentUtf8()).isEqualTo(SUCCESS.getBody());
 
     testing.waitAndAssertTraces(
         trace ->
@@ -570,10 +574,14 @@ void extractMultiBaggage() {
     AggregatedHttpRequest request =
         AggregatedHttpRequest.of(
             request(SUCCESS, method).headers().toBuilder()
+                // adding baggage header in w3c baggage format
                 .add("baggage", "test-baggage-key-1=test-baggage-value-1")
                 .add("baggage", "test-baggage-key-2=test-baggage-value-2")
                 .build());
-    client.execute(request).aggregate().join();
+    AggregatedHttpResponse response = client.execute(request).aggregate().join();
+
+    assertThat(response.status().code()).isEqualTo(SUCCESS.getStatus());
+    assertThat(response.contentUtf8()).isEqualTo(SUCCESS.getBody());
 
     testing.waitAndAssertTraces(
         trace ->