Detect message delivery loops

service/src/test/java/org/whispersystems/textsecuregcm/limits/MessageDeliveryLoopMonitorTest.java

@@ -0,0 +1,38 @@
+package org.whispersystems.textsecuregcm.limits;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.UUID;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
+import org.whispersystems.textsecuregcm.storage.Device;
+
+class MessageDeliveryLoopMonitorTest {
+
+  private MessageDeliveryLoopMonitor messageDeliveryLoopMonitor;
+
+  @RegisterExtension
+  static final RedisClusterExtension REDIS_CLUSTER_EXTENSION = RedisClusterExtension.builder().build();
+
+  @BeforeEach
+  void setUp() {
+    messageDeliveryLoopMonitor = new MessageDeliveryLoopMonitor(REDIS_CLUSTER_EXTENSION.getRedisCluster());
+  }
+
+  @Test
+  void incrementDeliveryAttemptCount() {
+    final UUID accountIdentifier = UUID.randomUUID();
+    final byte deviceId = Device.PRIMARY_ID;
+
+    assertEquals(1, messageDeliveryLoopMonitor.incrementDeliveryAttemptCount(accountIdentifier, deviceId, UUID.randomUUID()).join());
+    assertEquals(1, messageDeliveryLoopMonitor.incrementDeliveryAttemptCount(accountIdentifier, deviceId, UUID.randomUUID()).join());
+
+    final UUID repeatedDeliveryGuid = UUID.randomUUID();
+
+    for (int i = 1; i < 10; i++) {
+      assertEquals(i, messageDeliveryLoopMonitor.incrementDeliveryAttemptCount(accountIdentifier, deviceId, repeatedDeliveryGuid).join());
+    }
+  }
+}