diff --git a/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpGrpcRetryTest.java b/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpGrpcRetryTest.java
index 7b080a74a15..d44c4c43ec4 100644
--- a/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpGrpcRetryTest.java
+++ b/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpGrpcRetryTest.java
@@ -120,6 +120,10 @@ private static <T> void testRetryableStatusCodes(
 
       CompletableResultCode resultCode =
           exporter.apply(dataSupplier.get()).join(10, TimeUnit.SECONDS);
+      assertThat(resultCode.isDone())
+          .as("Exporter didn't complete in time. Consider increasing join timeout?")
+          .isTrue();
+
       boolean retryable =
           RetryUtil.retryableGrpcStatusCodes().contains(String.valueOf(code.value()));
       boolean expectedResult = retryable || code == Status.Code.OK;
@@ -152,6 +156,9 @@ private static <T> void testDefaultRetryPolicy(
     // Result should be failure, sever should have received maxAttempts requests
     CompletableResultCode resultCode =
         exporter.apply(dataSupplier.get()).join(10, TimeUnit.SECONDS);
+    assertThat(resultCode.isDone())
+        .as("Exporter didn't complete in time. Consider increasing join timeout?")
+        .isTrue();
     assertThat(resultCode.isSuccess()).isFalse();
     assertThat(serverRequestCountSupplier.get()).isEqualTo(maxAttempts);
   }
diff --git a/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpHttpRetryTest.java b/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpHttpRetryTest.java
index dc81a25e374..501824f1c91 100644
--- a/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpHttpRetryTest.java
+++ b/sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpHttpRetryTest.java
@@ -129,6 +129,10 @@ private static <T> void testRetryableStatusCodes(
 
       CompletableResultCode resultCode =
           exporter.apply(dataSupplier.get()).join(10, TimeUnit.SECONDS);
+      assertThat(resultCode.isDone())
+          .as("Exporter didn't complete in time. Consider increasing join timeout?")
+          .isTrue();
+
       boolean retryable = code != 200 && RetryUtil.retryableHttpResponseCodes().contains(code);
       boolean expectedResult = retryable || code == 200;
       assertThat(resultCode.isSuccess())
@@ -159,6 +163,9 @@ private static <T> void testDefaultRetryPolicy(
     // Result should be failure, sever should have received maxAttempts requests
     CompletableResultCode resultCode =
         exporter.apply(dataSupplier.get()).join(10, TimeUnit.SECONDS);
+    assertThat(resultCode.isDone())
+        .as("Exporter didn't complete in time. Consider increasing join timeout?")
+        .isTrue();
     assertThat(resultCode.isSuccess()).isFalse();
     assertThat(serverRequestCountSupplier.get()).isEqualTo(maxAttempts);
   }