diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepository.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepository.java
index 25cb21b..67f7eaf 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepository.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepository.java
@@ -20,18 +20,15 @@ import java.sql.Timestamp;
 import java.time.Instant;
 import java.util.Map;
 import java.util.Objects;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentSkipListMap;
 
 import reactor.core.publisher.Mono;
 
 import org.springframework.cloud.servicebroker.model.instance.OperationState;
 
-/**
- * @author Roy Clarkson
- */
 public class InMemoryServiceInstanceBindingStateRepository implements ServiceInstanceBindingStateRepository {
 
-	private final Map<BindingKey, ServiceInstanceState> states = new ConcurrentHashMap<>();
+	private final Map<BindingKey, ServiceInstanceState> states = new ConcurrentSkipListMap<>();
 
 	@Override
 	public Mono<ServiceInstanceState> saveState(String serviceInstanceId, String bindingId, OperationState state,
@@ -76,7 +73,7 @@ public class InMemoryServiceInstanceBindingStateRepository implements ServiceIns
 		return Mono.fromCallable(() -> this.states.containsKey(bindingKey));
 	}
 
-	private static class BindingKey {
+	private static class BindingKey implements Comparable<BindingKey> {
 
 		private final String serviceInstanceId;
 
@@ -121,6 +118,12 @@ public class InMemoryServiceInstanceBindingStateRepository implements ServiceIns
 				'}';
 		}
 
+		@Override
+		public int compareTo(BindingKey other) {
+			int compare = this.serviceInstanceId.compareTo(other.serviceInstanceId);
+			return compare == 0 ? this.bindingId.compareTo(other.bindingId) : compare;
+		}
+
 	}
 
 }
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepository.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepository.java
index 72bf3b9..3bdf0f1 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepository.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepository.java
@@ -19,7 +19,7 @@ package org.springframework.cloud.appbroker.state;
 import java.sql.Timestamp;
 import java.time.Instant;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentSkipListMap;
 
 import reactor.core.publisher.Mono;
 
@@ -27,7 +27,7 @@ import org.springframework.cloud.servicebroker.model.instance.OperationState;
 
 public class InMemoryServiceInstanceStateRepository implements ServiceInstanceStateRepository {
 
-	private final Map<String, ServiceInstanceState> states = new ConcurrentHashMap<>();
+	private final Map<String, ServiceInstanceState> states = new ConcurrentSkipListMap<>();
 
 	@Override
 	public Mono<ServiceInstanceState> saveState(String serviceInstanceId, OperationState state, String description) {
diff --git a/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepositoryTest.java b/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepositoryTest.java
index 0a1f904..9cfeb36 100644
--- a/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepositoryTest.java
+++ b/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceBindingStateRepositoryTest.java
@@ -19,7 +19,6 @@ package org.springframework.cloud.appbroker.state;
 import java.util.Calendar;
 
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Flux;
 import reactor.core.scheduler.Schedulers;
@@ -29,8 +28,6 @@ import org.springframework.cloud.servicebroker.model.instance.OperationState;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-@Disabled
-// See https://github.com/spring-cloud/spring-cloud-app-broker/issues/313
 class InMemoryServiceInstanceBindingStateRepositoryTest {
 
 	private InMemoryServiceInstanceBindingStateRepository stateRepository;
diff --git a/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepositoryTest.java b/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepositoryTest.java
index 0cca5a0..793830a 100644
--- a/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepositoryTest.java
+++ b/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/state/InMemoryServiceInstanceStateRepositoryTest.java
@@ -19,7 +19,6 @@ package org.springframework.cloud.appbroker.state;
 import java.util.Calendar;
 
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Flux;
 import reactor.core.scheduler.Schedulers;
@@ -29,8 +28,6 @@ import org.springframework.cloud.servicebroker.model.instance.OperationState;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-@Disabled
-// See https://github.com/spring-cloud/spring-cloud-app-broker/issues/313
 class InMemoryServiceInstanceStateRepositoryTest {
 
 	private InMemoryServiceInstanceStateRepository stateRepository;