diff --git a/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/AbstractAggregatorFunctionTests.java b/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/AbstractAggregatorFunctionTests.java
index 05e6f8c5..362d7114 100644
--- a/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/AbstractAggregatorFunctionTests.java
+++ b/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/AbstractAggregatorFunctionTests.java
@@ -21,6 +21,7 @@ import java.util.function.Function;
 import reactor.core.publisher.Flux;
 
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.integration.aggregator.AggregatingMessageHandler;
@@ -46,8 +47,10 @@ public abstract class AbstractAggregatorFunctionTests {
 	protected AggregatingMessageHandler aggregatingMessageHandler;
 
 	@SpringBootApplication
-	static class AggregatorFunctionTestApplication {
-
+	public static class AggregatorFunctionTestApplication {
+		public static void main(String[] args) {
+			SpringApplication.run(AggregatorFunctionTestApplication.class, args);
+		}
 	}
 
 }
diff --git a/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/DefaultAggregatorTests.java b/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/DefaultAggregatorTests.java
index 67147627..75a12a66 100644
--- a/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/DefaultAggregatorTests.java
+++ b/functions/function/aggregator-function/src/test/java/org/springframework/cloud/fn/aggregator/DefaultAggregatorTests.java
@@ -28,6 +28,7 @@ import org.springframework.integration.IntegrationMessageHeaderAccessor;
 import org.springframework.integration.store.SimpleMessageStore;
 import org.springframework.integration.support.MessageBuilder;
 import org.springframework.messaging.Message;
+import org.springframework.test.context.TestPropertySource;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -35,6 +36,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Artem Bilan
  * @author Corneil du Plessis
  */
+@TestPropertySource(properties = "aggregator.message-store-type=simple")
 public class DefaultAggregatorTests extends AbstractAggregatorFunctionTests {
 	private static final Logger logger = LoggerFactory.getLogger(DefaultAggregatorTests.class);
 
diff --git a/functions/function/header-filter-function/src/test/java/org/springframework/cloud/fn/header/filter/HeaderFilterFunctionApplicationTests.java b/functions/function/header-filter-function/src/test/java/org/springframework/cloud/fn/header/filter/HeaderFilterFunctionApplicationTests.java
index 6d94aa60..6c7ca30f 100644
--- a/functions/function/header-filter-function/src/test/java/org/springframework/cloud/fn/header/filter/HeaderFilterFunctionApplicationTests.java
+++ b/functions/function/header-filter-function/src/test/java/org/springframework/cloud/fn/header/filter/HeaderFilterFunctionApplicationTests.java
@@ -76,7 +76,7 @@ public class HeaderFilterFunctionApplicationTests {
 			.build();
 		Message<?> result = headerFilter.apply(message);
 		var headers = HeaderUtils.getNonReadOnlyHeaders(result);
-		assertThat(result.getHeaders().keySet()).isEqualTo(Set.of("pfBar"));
+		assertThat(headers).isEqualTo(Set.of("pfBar"));
 	}
 
 	@Test