diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.h b/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.h
index 42cd66a8c5f..5622d03dc71 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.h
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.h
@@ -45,6 +45,20 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)removeLog:(NSNumber *)logHash logTarget:(NSNumber *)logTarget;
 
+/** Removes a set of log fields specified by their filenames.
+ *
+ * @param logHashes The set of log files to remove.
+ * @param logTarget The log target the log files correspond to.
+ */
+- (void)removeLogs:(NSSet<NSNumber *> *)logHashes logTarget:(NSNumber *)logTarget;
+
+/** Converts a set of log hashes to a set of log files.
+ *
+ * @param logHashes A set of log hashes to get the files of.
+ * @return A set of equivalent length, containing all the filenames corresponding to the hashes.
+ */
+- (NSSet<NSURL *> *)logHashesToFiles:(NSSet<NSNumber *> *)logHashes;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.m b/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.m
index a590386fdcc..10864651e72 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.m
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/GDLLogStorage.m
@@ -56,7 +56,7 @@ - (instancetype)init {
   if (self) {
     _storageQueue = dispatch_queue_create("com.google.GDLLogStorage", DISPATCH_QUEUE_SERIAL);
     _logHashToLogFile = [[NSMutableDictionary alloc] init];
-    _logTargetToLogFileSet = [[NSMutableDictionary alloc] init];
+    _logTargetToLogHashSet = [[NSMutableDictionary alloc] init];
     _uploader = [GDLUploadCoordinator sharedInstance];
   }
   return self;
@@ -90,7 +90,7 @@ - (void)storeLog:(GDLLogEvent *)log {
 
     // Check the QoS, if it's high priority, notify the log target that it has a high priority log.
     if (shortLivedLog.qosTier == GDLLogQoSFast) {
-      NSSet<NSURL *> *allLogsForLogTarget = self.logTargetToLogFileSet[@(logTarget)];
+      NSSet<NSNumber *> *allLogsForLogTarget = self.logTargetToLogHashSet[@(logTarget)];
       [self.uploader forceUploadLogs:allLogsForLogTarget target:logTarget];
     }
 
@@ -117,13 +117,33 @@ - (void)removeLog:(NSNumber *)logHash logTarget:(NSNumber *)logTarget {
 
     // Remove from the tracking collections.
     [self.logHashToLogFile removeObjectForKey:logHash];
-    NSMutableSet<NSURL *> *logFiles = self.logTargetToLogFileSet[logTarget];
-    GDLAssert(logFiles, @"There wasn't a logSet for this logTarget.");
-    [logFiles removeObject:logFile];
+    NSMutableSet<NSNumber *> *logHashes = self.logTargetToLogHashSet[logTarget];
+    GDLAssert(logHashes, @"There wasn't a logSet for this logTarget.");
+    [logHashes removeObject:logHash];
     // It's fine to not remove the set if it's empty.
   });
 }
 
+- (void)removeLogs:(NSSet<NSNumber *> *)logHashes logTarget:(NSNumber *)logTarget {
+  dispatch_sync(_storageQueue, ^{
+    for (NSNumber *logHash in logHashes) {
+      [self removeLog:logHash logTarget:logTarget];
+    }
+  });
+}
+
+- (NSSet<NSURL *> *)logHashesToFiles:(NSSet<NSNumber *> *)logHashes {
+  NSMutableSet<NSURL *> *logFiles = [[NSMutableSet alloc] init];
+  dispatch_sync(_storageQueue, ^{
+    for (NSNumber *hashNumber in logHashes) {
+      NSURL *logURL = self.logHashToLogFile[hashNumber];
+      GDLAssert(logURL, @"A log file URL couldn't be found for the given hash");
+      [logFiles addObject:logURL];
+    }
+  });
+  return logFiles;
+}
+
 #pragma mark - Private helper methods
 
 /** Creates the log directory if it does not exist. */
@@ -170,13 +190,15 @@ - (NSURL *)saveLogProtoToDisk:(NSData *)logProtoBytes logHash:(NSUInteger)logHas
  */
 - (void)addLogToTrackingCollections:(GDLLogEvent *)log logFile:(NSURL *)logFile {
   NSInteger logTarget = log.logTarget;
-  self.logHashToLogFile[@(log.hash)] = logFile;
-  NSMutableSet<NSURL *> *logs = self.logTargetToLogFileSet[@(logTarget)];
+  NSNumber *logHash = @(log.hash);
+  NSNumber *logTargetNumber = @(logTarget);
+  self.logHashToLogFile[logHash] = logFile;
+  NSMutableSet<NSNumber *> *logs = self.logTargetToLogHashSet[logTargetNumber];
   if (logs) {
-    [logs addObject:logFile];
+    [logs addObject:logHash];
   } else {
-    NSMutableSet<NSURL *> *logSet = [NSMutableSet setWithObject:logFile];
-    self.logTargetToLogFileSet[@(logTarget)] = logSet;
+    NSMutableSet<NSNumber *> *logSet = [NSMutableSet setWithObject:logHash];
+    self.logTargetToLogHashSet[logTargetNumber] = logSet;
   }
 }
 
@@ -185,8 +207,8 @@ - (void)addLogToTrackingCollections:(GDLLogEvent *)log logFile:(NSURL *)logFile
 /** The NSKeyedCoder key for the logHashToFile property. */
 static NSString *const kGDLLogHashToLogFileKey = @"logHashToLogFileKey";
 
-/** The NSKeyedCoder key for the logTargetToLogFileSet property. */
-static NSString *const kGDLLogTargetToLogSetKey = @"logTargetToLogFileSetKey";
+/** The NSKeyedCoder key for the logTargetToLogHashSet property. */
+static NSString *const kGDLLogTargetToLogHashSetKey = @"logTargetToLogHashSetKey";
 
 + (BOOL)supportsSecureCoding {
   return YES;
@@ -199,8 +221,8 @@ - (instancetype)initWithCoder:(NSCoder *)aDecoder {
     Class NSMutableDictionaryClass = [NSMutableDictionary class];
     sharedInstance->_logHashToLogFile = [aDecoder decodeObjectOfClass:NSMutableDictionaryClass
                                                                forKey:kGDLLogHashToLogFileKey];
-    sharedInstance->_logTargetToLogFileSet =
-        [aDecoder decodeObjectOfClass:NSMutableDictionaryClass forKey:kGDLLogTargetToLogSetKey];
+    sharedInstance->_logTargetToLogHashSet =
+        [aDecoder decodeObjectOfClass:NSMutableDictionaryClass forKey:kGDLLogTargetToLogHashSetKey];
   });
   return sharedInstance;
 }
@@ -209,7 +231,8 @@ - (void)encodeWithCoder:(NSCoder *)aCoder {
   GDLLogStorage *sharedInstance = [self.class sharedInstance];
   dispatch_sync(sharedInstance.storageQueue, ^{
     [aCoder encodeObject:sharedInstance->_logHashToLogFile forKey:kGDLLogHashToLogFileKey];
-    [aCoder encodeObject:sharedInstance->_logTargetToLogFileSet forKey:kGDLLogTargetToLogSetKey];
+    [aCoder encodeObject:sharedInstance->_logTargetToLogHashSet
+                  forKey:kGDLLogTargetToLogHashSetKey];
   });
 }
 
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/GDLRegistrar.m b/GoogleDataLogger/GoogleDataLogger/Classes/GDLRegistrar.m
index 3d647301c91..d23baf42467 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/GDLRegistrar.m
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/GDLRegistrar.m
@@ -33,13 +33,13 @@ - (instancetype)init {
   self = [super init];
   if (self) {
     _logTargetToPrioritizer = [[NSMutableDictionary alloc] init];
-    _logTargetToBackend = [[NSMutableDictionary alloc] init];
+    _logTargetToUploader = [[NSMutableDictionary alloc] init];
   }
   return self;
 }
 
 - (void)registerBackend:(id<GDLLogUploader>)backend forLogTarget:(GDLLogTarget)logTarget {
-  self.logTargetToBackend[@(logTarget)] = backend;
+  self.logTargetToUploader[@(logTarget)] = backend;
 }
 
 - (void)registerLogPrioritizer:(id<GDLLogPrioritizer>)prioritizer
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.h b/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.h
index 8ecaf34d872..71e4d0f6648 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.h
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.h
@@ -33,8 +33,11 @@ NS_ASSUME_NONNULL_BEGIN
 
 /** Forces the backend specified by the target to upload the provided set of logs. This should only
  * ever happen when the QoS tier of a log requires it.
+ *
+ * @param logHashes The set of log hashes to force upload.
+ * @param logTarget The log target that should force an upload.
  */
-- (void)forceUploadLogs:(NSSet<NSURL *> *)logFiles target:(GDLLogTarget)logTarget;
+- (void)forceUploadLogs:(NSSet<NSNumber *> *)logHashes target:(GDLLogTarget)logTarget;
 
 @end
 
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.m b/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.m
index 277da32f223..f1baa389ee9 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.m
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/GDLUploadCoordinator.m
@@ -29,7 +29,7 @@ + (instancetype)sharedInstance {
   return sharedUploader;
 }
 
-- (void)forceUploadLogs:(NSSet<NSURL *> *)logFiles target:(GDLLogTarget)logTarget {
+- (void)forceUploadLogs:(NSSet<NSNumber *> *)logHashes target:(GDLLogTarget)logTarget {
   // Ask the prioritizer of the target for some logs
 }
 
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLLogStorage_Private.h b/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLLogStorage_Private.h
index 6f3ff0a7585..24b90ad4183 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLLogStorage_Private.h
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLLogStorage_Private.h
@@ -28,7 +28,7 @@
 
 /** A map of logTargets to a set of log hash values. */
 @property(nonatomic)
-    NSMutableDictionary<NSNumber *, NSMutableSet<NSURL *> *> *logTargetToLogFileSet;
+    NSMutableDictionary<NSNumber *, NSMutableSet<NSNumber *> *> *logTargetToLogHashSet;
 
 /** The log uploader instance to use. */
 @property(nonatomic) GDLUploadCoordinator *uploader;
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLRegistrar_Private.h b/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLRegistrar_Private.h
index 509ea9b9253..f133cffd2b4 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLRegistrar_Private.h
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/Private/GDLRegistrar_Private.h
@@ -19,7 +19,7 @@
 @interface GDLRegistrar ()
 
 /** A map of logTargets to backend implementations. */
-@property(nonatomic) NSMutableDictionary<NSNumber *, id<GDLLogUploader>> *logTargetToBackend;
+@property(nonatomic) NSMutableDictionary<NSNumber *, id<GDLLogUploader>> *logTargetToUploader;
 
 /** A map of logTargets to prioritizer implementations. */
 @property(nonatomic) NSMutableDictionary<NSNumber *, id<GDLLogPrioritizer>> *logTargetToPrioritizer;
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogTargets.h b/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogTargets.h
new file mode 100644
index 00000000000..c373e5252be
--- /dev/null
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogTargets.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2019 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <Foundation/Foundation.h>
+
+/** The list of targets supported by the shared logging infrastructure. If adding a new target,
+ * please use the previous value +1, and increment GDLLogTargetLast by 1.
+ */
+typedef NS_ENUM(NSInteger, GDLLogTarget) {
+
+  /** The CCT log target. */
+  kGDLLogTargetCCT = 1000,
+
+  GDLLogTargetLast = 1001
+};
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogUploader.h b/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogUploader.h
index fded1deddb1..0d41b1a9e6f 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogUploader.h
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogUploader.h
@@ -16,13 +16,21 @@
 
 #import <Foundation/Foundation.h>
 
+#import <GoogleDataLogger/GDLClock.h>
+#import <GoogleDataLogger/GDLLogTargets.h>
+
 NS_ASSUME_NONNULL_BEGIN
 
 /** A convenient typedef to define the block to be called upon completion of an upload to the
  * backend.
+ *
+ * target: The log target that was uploading.
+ * nextUploadAttemptUTC: The desired next upload attempt time.
+ * uploadError: Populated with any upload error. If non-nil, a retry will be attempted.
  */
-typedef void (^GDLBackendCompletionBlock)(NSSet<NSURL *> *_Nullable successfulUploads,
-                                          NSSet<NSURL *> *_Nullable unsuccessfulUploads);
+typedef void (^GDLUploaderCompletionBlock)(GDLLogTarget target,
+                                           GDLClock *nextUploadAttemptUTC,
+                                           NSError *_Nullable uploadError);
 
 /** This protocol defines the common interface for logging backend implementations. */
 @protocol GDLLogUploader <NSObject>
@@ -36,7 +44,7 @@ typedef void (^GDLBackendCompletionBlock)(NSSet<NSURL *> *_Nullable successfulUp
  *   - successfulUploads: The set of filenames uploaded successfully.
  *   - unsuccessfulUploads: The set of filenames not uploaded successfully.
  */
-- (void)uploadLogs:(NSSet<NSURL *> *)logFiles onComplete:(GDLBackendCompletionBlock)onComplete;
+- (void)uploadLogs:(NSSet<NSURL *> *)logFiles onComplete:(GDLUploaderCompletionBlock)onComplete;
 
 @end
 
diff --git a/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLRegistrar.h b/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLRegistrar.h
index 75c578da0d2..da3f583a41e 100644
--- a/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLRegistrar.h
+++ b/GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLRegistrar.h
@@ -17,17 +17,11 @@
 #import <Foundation/Foundation.h>
 
 #import <GoogleDataLogger/GDLLogPrioritizer.h>
+#import <GoogleDataLogger/GDLLogTargets.h>
 #import <GoogleDataLogger/GDLLogUploader.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
-/** The list of targets supported by the shared logging infrastructure. */
-typedef NS_ENUM(NSInteger, GDLLogTarget) {
-
-  /** The CCT log target. */
-  kGDLLogTargetCCT = 1000
-};
-
 /** Manages the registration of log targets with the logging SDK. */
 @interface GDLRegistrar : NSObject
 
diff --git a/GoogleDataLogger/Tests/Unit/Categories/GDLLogStorage+Testing.m b/GoogleDataLogger/Tests/Unit/Categories/GDLLogStorage+Testing.m
index e728748fe66..22bec982c07 100644
--- a/GoogleDataLogger/Tests/Unit/Categories/GDLLogStorage+Testing.m
+++ b/GoogleDataLogger/Tests/Unit/Categories/GDLLogStorage+Testing.m
@@ -20,7 +20,7 @@ @implementation GDLLogStorage (Testing)
 
 - (void)reset {
   dispatch_sync(self.storageQueue, ^{
-    [self.logTargetToLogFileSet removeAllObjects];
+    [self.logTargetToLogHashSet removeAllObjects];
     [self.logHashToLogFile removeAllObjects];
   });
 }
diff --git a/GoogleDataLogger/Tests/Unit/Categories/GDLRegistrar+Testing.m b/GoogleDataLogger/Tests/Unit/Categories/GDLRegistrar+Testing.m
index 57a88b5e5f6..5aa9a2d5a10 100644
--- a/GoogleDataLogger/Tests/Unit/Categories/GDLRegistrar+Testing.m
+++ b/GoogleDataLogger/Tests/Unit/Categories/GDLRegistrar+Testing.m
@@ -22,7 +22,7 @@ @implementation GDLRegistrar (Testing)
 
 - (void)reset {
   [self.logTargetToPrioritizer removeAllObjects];
-  [self.logTargetToBackend removeAllObjects];
+  [self.logTargetToUploader removeAllObjects];
 }
 
 @end
diff --git a/GoogleDataLogger/Tests/Unit/GDLLogStorageTest.m b/GoogleDataLogger/Tests/Unit/GDLLogStorageTest.m
index 32a46d9ebee..9e5f5b61cac 100644
--- a/GoogleDataLogger/Tests/Unit/GDLLogStorageTest.m
+++ b/GoogleDataLogger/Tests/Unit/GDLLogStorageTest.m
@@ -87,7 +87,7 @@ - (void)testStoreLog {
   }
   dispatch_sync([GDLLogStorage sharedInstance].storageQueue, ^{
     XCTAssertEqual([GDLLogStorage sharedInstance].logHashToLogFile.count, 1);
-    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogFileSet[@(logTarget)].count, 1);
+    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogHashSet[@(logTarget)].count, 1);
     NSURL *logFile = [GDLLogStorage sharedInstance].logHashToLogFile[@(logHash)];
     XCTAssertNotNil(logFile);
     XCTAssertTrue([[NSFileManager defaultManager] fileExistsAtPath:logFile.path]);
@@ -116,7 +116,43 @@ - (void)testRemoveLog {
   dispatch_sync([GDLLogStorage sharedInstance].storageQueue, ^{
     XCTAssertFalse([[NSFileManager defaultManager] fileExistsAtPath:logFile.path]);
     XCTAssertEqual([GDLLogStorage sharedInstance].logHashToLogFile.count, 0);
-    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogFileSet[@(logTarget)].count, 0);
+    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogHashSet[@(logTarget)].count, 0);
+  });
+}
+
+/** Tests removing a set of logs */
+- (void)testRemoveLogs {
+  GDLLogStorage *storage = [GDLLogStorage sharedInstance];
+  NSUInteger log1Hash, log2Hash, log3Hash;
+
+  // logEvents are autoreleased, and the pool needs to drain.
+  @autoreleasepool {
+    GDLLogEvent *logEvent = [[GDLLogEvent alloc] initWithLogMapID:@"404" logTarget:logTarget];
+    logEvent.extensionBytes = [@"testString1" dataUsingEncoding:NSUTF8StringEncoding];
+    log1Hash = logEvent.hash;
+    XCTAssertNoThrow([storage storeLog:logEvent]);
+
+    logEvent = [[GDLLogEvent alloc] initWithLogMapID:@"100" logTarget:logTarget];
+    logEvent.extensionBytes = [@"testString2" dataUsingEncoding:NSUTF8StringEncoding];
+    log2Hash = logEvent.hash;
+    XCTAssertNoThrow([storage storeLog:logEvent]);
+
+    logEvent = [[GDLLogEvent alloc] initWithLogMapID:@"404" logTarget:logTarget];
+    logEvent.extensionBytes = [@"testString3" dataUsingEncoding:NSUTF8StringEncoding];
+    log3Hash = logEvent.hash;
+    XCTAssertNoThrow([storage storeLog:logEvent]);
+  }
+  NSSet<NSNumber *> *logHashSet = [NSSet setWithObjects:@(log1Hash), @(log2Hash), @(log3Hash), nil];
+  NSSet<NSURL *> *logFiles = [storage logHashesToFiles:logHashSet];
+  [storage removeLogs:logHashSet logTarget:@(logTarget)];
+  dispatch_sync(storage.storageQueue, ^{
+    XCTAssertNil(storage.logHashToLogFile[@(log1Hash)]);
+    XCTAssertNil(storage.logHashToLogFile[@(log2Hash)]);
+    XCTAssertNil(storage.logHashToLogFile[@(log3Hash)]);
+    XCTAssertEqual(storage.logTargetToLogHashSet[@(logTarget)].count, 0);
+    for (NSURL *logFile in logFiles) {
+      XCTAssertFalse([[NSFileManager defaultManager] fileExistsAtPath:logFile.path]);
+    }
   });
 }
 
@@ -143,7 +179,7 @@ - (void)testStoreMultipleLogs {
   }
   dispatch_sync([GDLLogStorage sharedInstance].storageQueue, ^{
     XCTAssertEqual([GDLLogStorage sharedInstance].logHashToLogFile.count, 3);
-    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogFileSet[@(logTarget)].count, 3);
+    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogHashSet[@(logTarget)].count, 3);
 
     NSURL *log1File = [GDLLogStorage sharedInstance].logHashToLogFile[@(log1Hash)];
     XCTAssertNotNil(log1File);
@@ -196,7 +232,7 @@ - (void)testLogEventDeallocationIsEnforced {
   dispatch_sync([GDLLogStorage sharedInstance].storageQueue, ^{
     XCTAssertFalse([[NSFileManager defaultManager] fileExistsAtPath:logFile.path]);
     XCTAssertEqual([GDLLogStorage sharedInstance].logHashToLogFile.count, 0);
-    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogFileSet[@(logTarget)].count, 0);
+    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogHashSet[@(logTarget)].count, 0);
   });
 }
 
@@ -237,7 +273,7 @@ - (void)testQoSTierFast {
   dispatch_sync([GDLLogStorage sharedInstance].storageQueue, ^{
     XCTAssertTrue(self.uploaderFake.forceUploadCalled);
     XCTAssertEqual([GDLLogStorage sharedInstance].logHashToLogFile.count, 1);
-    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogFileSet[@(logTarget)].count, 1);
+    XCTAssertEqual([GDLLogStorage sharedInstance].logTargetToLogHashSet[@(logTarget)].count, 1);
     NSURL *logFile = [GDLLogStorage sharedInstance].logHashToLogFile[@(logHash)];
     XCTAssertNotNil(logFile);
     XCTAssertTrue([[NSFileManager defaultManager] fileExistsAtPath:logFile.path]);
@@ -247,4 +283,36 @@ - (void)testQoSTierFast {
   });
 }
 
+/** Tests convert a set of log hashes to a set of log file URLS. */
+- (void)testLogHashesToFiles {
+  GDLLogStorage *storage = [GDLLogStorage sharedInstance];
+  NSUInteger log1Hash, log2Hash, log3Hash;
+
+  // logEvents are autoreleased, and the pool needs to drain.
+  @autoreleasepool {
+    GDLLogEvent *logEvent = [[GDLLogEvent alloc] initWithLogMapID:@"404" logTarget:logTarget];
+    logEvent.extensionBytes = [@"testString1" dataUsingEncoding:NSUTF8StringEncoding];
+    log1Hash = logEvent.hash;
+    XCTAssertNoThrow([storage storeLog:logEvent]);
+
+    logEvent = [[GDLLogEvent alloc] initWithLogMapID:@"100" logTarget:logTarget];
+    logEvent.extensionBytes = [@"testString2" dataUsingEncoding:NSUTF8StringEncoding];
+    log2Hash = logEvent.hash;
+    XCTAssertNoThrow([storage storeLog:logEvent]);
+
+    logEvent = [[GDLLogEvent alloc] initWithLogMapID:@"404" logTarget:logTarget];
+    logEvent.extensionBytes = [@"testString3" dataUsingEncoding:NSUTF8StringEncoding];
+    log3Hash = logEvent.hash;
+    XCTAssertNoThrow([storage storeLog:logEvent]);
+  }
+  NSSet<NSNumber *> *logHashSet = [NSSet setWithObjects:@(log1Hash), @(log2Hash), @(log3Hash), nil];
+  NSSet<NSURL *> *logFiles = [storage logHashesToFiles:logHashSet];
+  dispatch_sync(storage.storageQueue, ^{
+    XCTAssertEqual(logFiles.count, 3);
+    XCTAssertTrue([logFiles containsObject:storage.logHashToLogFile[@(log1Hash)]]);
+    XCTAssertTrue([logFiles containsObject:storage.logHashToLogFile[@(log2Hash)]]);
+    XCTAssertTrue([logFiles containsObject:storage.logHashToLogFile[@(log3Hash)]]);
+  });
+}
+
 @end
diff --git a/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.h b/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.h
index 194d9a55c9f..40945237b0f 100644
--- a/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.h
+++ b/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.h
@@ -27,7 +27,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /** A block that can be ran in -uploadLogs:onComplete:. */
 @property(nullable, nonatomic) void (^uploadLogsBlock)
-    (NSSet<NSURL *> *logFiles, GDLBackendCompletionBlock completionBlock);
+    (NSSet<NSURL *> *logFiles, GDLUploaderCompletionBlock completionBlock);
 
 @end
 
diff --git a/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.m b/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.m
index 3c2bfd61b9a..0b013f443da 100644
--- a/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.m
+++ b/GoogleDataLogger/Tests/Unit/Helpers/GDLTestUploader.m
@@ -18,11 +18,11 @@
 
 @implementation GDLTestUploader
 
-- (void)uploadLogs:(NSSet<NSURL *> *)logFiles onComplete:(GDLBackendCompletionBlock)onComplete {
+- (void)uploadLogs:(NSSet<NSURL *> *)logFiles onComplete:(GDLUploaderCompletionBlock)onComplete {
   if (_uploadLogsBlock) {
     _uploadLogsBlock(logFiles, onComplete);
   } else if (onComplete) {
-    onComplete(nil, nil);
+    onComplete(kGDLLogTargetCCT, [GDLClock snapshot], nil);
   }
 }