Add a test synchronization script (#1303)

* Add a project sync script
* Give an error if the configuration references a group that doesn't exist
* Fix hard_assert_test reference
* Run sync_project to sort all project elements

3 files changed, 714 insertions, 143 deletions

diff --git a/Firestore/Example/Firestore.xcodeproj/project.pbxproj b/Firestore/Example/Firestore.xcodeproj/project.pbxproj
index fd6d9ba..836017b 100644
--- a/Firestore/Example/Firestore.xcodeproj/project.pbxproj
+++ b/Firestore/Example/Firestore.xcodeproj/project.pbxproj
@@ -148,6 +148,7 @@
 		71719F9F1E33DC2100824A3D /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 71719F9D1E33DC2100824A3D /* LaunchScreen.storyboard */; };
 		7346E61D20325C6900FD6CEF /* FSTDispatchQueueTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 7346E61C20325C6900FD6CEF /* FSTDispatchQueueTests.mm */; };
 		73866AA12082B0A5009BB4FF /* FIRArrayTransformTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 73866A9F2082B069009BB4FF /* FIRArrayTransformTests.mm */; };
+		73FE5066020EF9B2892C86BF /* hard_assert_test.cc in Sources */ = {isa = PBXBuildFile; fileRef = 444B7AB3F5A2929070CB1363 /* hard_assert_test.cc */; };
 		873B8AEB1B1F5CCA007FD442 /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 873B8AEA1B1F5CCA007FD442 /* Main.storyboard */; };
 		8C82D4D3F9AB63E79CC52DC8 /* Pods_Firestore_IntegrationTests_iOS.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = ECEBABC7E7B693BE808A1052 /* Pods_Firestore_IntegrationTests_iOS.framework */; };
 		AB356EF7200EA5EB0089B766 /* field_value_test.cc in Sources */ = {isa = PBXBuildFile; fileRef = AB356EF6200EA5EB0089B766 /* field_value_test.cc */; };
@@ -256,6 +257,7 @@
 		3B843E4A1F3930A400548890 /* remote_store_spec_test.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = remote_store_spec_test.json; sourceTree = "<group>"; };
 		3C81DE3772628FE297055662 /* Pods-Firestore_Example_iOS.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Firestore_Example_iOS.debug.xcconfig"; path = "Pods/Target Support Files/Pods-Firestore_Example_iOS/Pods-Firestore_Example_iOS.debug.xcconfig"; sourceTree = "<group>"; };
 		3F0992A4B83C60841C52E960 /* Pods-Firestore_Example_iOS.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Firestore_Example_iOS.release.xcconfig"; path = "Pods/Target Support Files/Pods-Firestore_Example_iOS/Pods-Firestore_Example_iOS.release.xcconfig"; sourceTree = "<group>"; };
+		444B7AB3F5A2929070CB1363 /* hard_assert_test.cc */ = {isa = PBXFileReference; includeInIndex = 1; path = hard_assert_test.cc; sourceTree = "<group>"; };
 		54131E9620ADE678001DF3FF /* string_format_test.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = string_format_test.cc; sourceTree = "<group>"; };
 		54511E8D209805F8005BD28F /* hashing_test.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = hashing_test.cc; sourceTree = "<group>"; };
 		5467FAFF203E56F8009C9584 /* FIRFirestoreTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = FIRFirestoreTests.mm; sourceTree = "<group>"; };
@@ -468,9 +470,9 @@
 			buildActionMask = 2147483647;
 			files = (
 				6003F590195388D20070C39A /* CoreGraphics.framework in Frameworks */,
-				6003F592195388D20070C39A /* UIKit.framework in Frameworks */,
 				6003F58E195388D20070C39A /* Foundation.framework in Frameworks */,
 				C8D3CE2343E53223E6487F2C /* Pods_Firestore_Example_iOS.framework in Frameworks */,
+				6003F592195388D20070C39A /* UIKit.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -478,10 +480,10 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				6003F5B0195388D20070C39A /* XCTest.framework in Frameworks */,
-				6003F5B2195388D20070C39A /* UIKit.framework in Frameworks */,
 				6003F5B1195388D20070C39A /* Foundation.framework in Frameworks */,
 				5D405BE298CE4692CB00790A /* Pods_Firestore_Tests_iOS.framework in Frameworks */,
+				6003F5B2195388D20070C39A /* UIKit.framework in Frameworks */,
+				6003F5B0195388D20070C39A /* XCTest.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -489,10 +491,10 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				DE03B2D41F2149D600A30B9C /* XCTest.framework in Frameworks */,
-				DE03B2D51F2149D600A30B9C /* UIKit.framework in Frameworks */,
 				DE03B2D61F2149D600A30B9C /* Foundation.framework in Frameworks */,
 				8C82D4D3F9AB63E79CC52DC8 /* Pods_Firestore_IntegrationTests_iOS.framework in Frameworks */,
+				DE03B2D51F2149D600A30B9C /* UIKit.framework in Frameworks */,
+				DE03B2D41F2149D600A30B9C /* XCTest.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -549,14 +551,14 @@
 				B6FB4687208F9B9100554BA2 /* executor_std_test.cc */,
 				B6FB4688208F9B9100554BA2 /* executor_test.cc */,
 				B6FB468A208F9B9100554BA2 /* executor_test.h */,
-				54131E9820AE076C001DF3FF /* hard_assert_test.cc */,
+				444B7AB3F5A2929070CB1363 /* hard_assert_test.cc */,
 				54511E8D209805F8005BD28F /* hashing_test.cc */,
 				54A0353420A3D8CB003E0143 /* iterator_adaptors_test.cc */,
 				54C2294E1FECABAE007D065B /* log_test.cc */,
 				AB380D03201BC6E400D97691 /* ordered_code_test.cc */,
 				54740A531FC913E500713A1A /* secure_random_test.cc */,
-				54A0352B20A3B3D7003E0143 /* status_test_util.h */,
 				54A0352C20A3B3D7003E0143 /* status_test.cc */,
+				54A0352B20A3B3D7003E0143 /* status_test_util.h */,
 				54A0352D20A3B3D7003E0143 /* statusor_test.cc */,
 				54131E9620ADE678001DF3FF /* string_format_test.cc */,
 				AB380CFC201A2EE200D97691 /* string_util_test.cc */,
@@ -640,10 +642,10 @@
 			isa = PBXGroup;
 			children = (
 				6003F58A195388D20070C39A /* Firestore_Example_iOS.app */,
-				6003F5AE195388D20070C39A /* Firestore_Tests_iOS.xctest */,
 				DE03B2E91F2149D600A30B9C /* Firestore_IntegrationTests_iOS.xctest */,
-				DE0761E41F2FE611003233AF /* SwiftBuildTest.app */,
 				54C9EDF12040E16300A969CD /* Firestore_SwiftTests_iOS.xctest */,
+				6003F5AE195388D20070C39A /* Firestore_Tests_iOS.xctest */,
+				DE0761E41F2FE611003233AF /* SwiftBuildTest.app */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -651,15 +653,15 @@
 		6003F58C195388D20070C39A /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
-				6003F58D195388D20070C39A /* Foundation.framework */,
 				6003F58F195388D20070C39A /* CoreGraphics.framework */,
-				6003F591195388D20070C39A /* UIKit.framework */,
-				6003F5AF195388D20070C39A /* XCTest.framework */,
+				6003F58D195388D20070C39A /* Foundation.framework */,
 				5918805E993304321A05E82B /* Pods_Firestore_Example_iOS.framework */,
 				BB92EB03E3F92485023F64ED /* Pods_Firestore_Example_iOS_Firestore_SwiftTests_iOS.framework */,
 				379B34A1536045869826D82A /* Pods_Firestore_Example_iOS_SwiftBuildTest.framework */,
 				ECEBABC7E7B693BE808A1052 /* Pods_Firestore_IntegrationTests_iOS.framework */,
 				2B50B3A0DF77100EEE887891 /* Pods_Firestore_Tests_iOS.framework */,
+				6003F591195388D20070C39A /* UIKit.framework */,
+				6003F5AF195388D20070C39A /* XCTest.framework */,
 			);
 			name = Frameworks;
 			sourceTree = "<group>";
@@ -667,14 +669,14 @@
 		6003F593195388D20070C39A /* iOS */ = {
 			isa = PBXGroup;
 			children = (
+				6003F594195388D20070C39A /* Supporting Files */,
 				6003F59C195388D20070C39A /* FIRAppDelegate.h */,
 				6003F59D195388D20070C39A /* FIRAppDelegate.m */,
-				873B8AEA1B1F5CCA007FD442 /* Main.storyboard */,
 				6003F5A5195388D20070C39A /* FIRViewController.h */,
 				6003F5A6195388D20070C39A /* FIRViewController.m */,
-				71719F9D1E33DC2100824A3D /* LaunchScreen.storyboard */,
 				6003F5A8195388D20070C39A /* Images.xcassets */,
-				6003F594195388D20070C39A /* Supporting Files */,
+				71719F9D1E33DC2100824A3D /* LaunchScreen.storyboard */,
+				873B8AEA1B1F5CCA007FD442 /* Main.storyboard */,
 			);
 			path = iOS;
 			sourceTree = "<group>";
@@ -700,8 +702,8 @@
 				DE51B17B1F0D48AC0013853F /* Model */,
 				DE51B1B21F0D48AC0013853F /* Remote */,
 				DE51B1931F0D48AC0013853F /* SpecTests */,
-				DE51B1851F0D48AC0013853F /* Util */,
 				6003F5B6195388D20070C39A /* Supporting Files */,
+				DE51B1851F0D48AC0013853F /* Util */,
 			);
 			path = Tests;
 			sourceTree = "<group>";
@@ -709,8 +711,8 @@
 		6003F5B6195388D20070C39A /* Supporting Files */ = {
 			isa = PBXGroup;
 			children = (
-				6003F5B7195388D20070C39A /* Tests-Info.plist */,
 				6003F5B8195388D20070C39A /* InfoPlist.strings */,
+				6003F5B7195388D20070C39A /* Tests-Info.plist */,
 			);
 			name = "Supporting Files";
 			sourceTree = "<group>";
@@ -719,8 +721,8 @@
 			isa = PBXGroup;
 			children = (
 				8E002F4AD5D9B6197C940847 /* Firestore.podspec */,
-				D3CC3DC5338DCAF43A211155 /* README.md */,
 				12F4357299652983A615F886 /* LICENSE */,
+				D3CC3DC5338DCAF43A211155 /* README.md */,
 			);
 			name = "Podspec Metadata";
 			sourceTree = "<group>";
@@ -728,12 +730,12 @@
 		AAEA2A72CFD1FA5AD34462F7 /* Pods */ = {
 			isa = PBXGroup;
 			children = (
-				3C81DE3772628FE297055662 /* Pods-Firestore_Example_iOS.debug.xcconfig */,
-				3F0992A4B83C60841C52E960 /* Pods-Firestore_Example_iOS.release.xcconfig */,
 				69E6C311558EC77729A16CF1 /* Pods-Firestore_Example_iOS-Firestore_SwiftTests_iOS.debug.xcconfig */,
 				11984BA0A99D7A7ABA5B0D90 /* Pods-Firestore_Example_iOS-Firestore_SwiftTests_iOS.release.xcconfig */,
 				05C3D82261C3BE976889FF09 /* Pods-Firestore_Example_iOS-SwiftBuildTest.debug.xcconfig */,
 				74ACEC3603BE58B57A7E8D4C /* Pods-Firestore_Example_iOS-SwiftBuildTest.release.xcconfig */,
+				3C81DE3772628FE297055662 /* Pods-Firestore_Example_iOS.debug.xcconfig */,
+				3F0992A4B83C60841C52E960 /* Pods-Firestore_Example_iOS.release.xcconfig */,
 				1277F98C20D2DF0867496976 /* Pods-Firestore_IntegrationTests_iOS.debug.xcconfig */,
 				F354C0FE92645B56A6C6FD44 /* Pods-Firestore_IntegrationTests_iOS.release.xcconfig */,
 				E592181BFD7C53C305123739 /* Pods-Firestore_Tests_iOS.debug.xcconfig */,
@@ -813,6 +815,7 @@
 				5492E0872021552A00B64F25 /* FSTLevelDBMutationQueueTests.mm */,
 				5492E0982021552C00B64F25 /* FSTLevelDBQueryCacheTests.mm */,
 				5492E0922021552B00B64F25 /* FSTLevelDBRemoteDocumentCacheTests.mm */,
+				132E36BB104830BD806351AC /* FSTLevelDBTransactionTests.mm */,
 				5492E08A2021552A00B64F25 /* FSTLocalSerializerTests.mm */,
 				5492E0912021552B00B64F25 /* FSTLocalStoreTests.h */,
 				5492E0832021552A00B64F25 /* FSTLocalStoreTests.mm */,
@@ -830,7 +833,6 @@
 				5492E0852021552A00B64F25 /* FSTRemoteDocumentCacheTests.h */,
 				5492E09C2021552D00B64F25 /* FSTRemoteDocumentCacheTests.mm */,
 				5492E0932021552B00B64F25 /* StringViewTests.mm */,
-				132E36BB104830BD806351AC /* FSTLevelDBTransactionTests.mm */,
 			);
 			path = Local;
 			sourceTree = "<group>";
@@ -838,12 +840,12 @@
 		DE51B17B1F0D48AC0013853F /* Model */ = {
 			isa = PBXGroup;
 			children = (
-				54A0352320A3AEC3003E0143 /* field_transform_test.mm */,
 				5492E0B22021555000B64F25 /* FSTDocumentKeyTests.mm */,
 				5492E0B32021555100B64F25 /* FSTDocumentSetTests.mm */,
 				5492E0B62021555100B64F25 /* FSTDocumentTests.mm */,
 				5492E0B82021555100B64F25 /* FSTFieldValueTests.mm */,
 				5492E0B72021555100B64F25 /* FSTMutationTests.mm */,
+				54A0352320A3AEC3003E0143 /* field_transform_test.mm */,
 				54A0352220A3AEC3003E0143 /* transform_operations_test.mm */,
 			);
 			path = Model;
@@ -873,6 +875,7 @@
 			isa = PBXGroup;
 			children = (
 				5492E0382021401E00B64F25 /* FSTAssertTests.mm */,
+				7346E61C20325C6900FD6CEF /* FSTDispatchQueueTests.mm */,
 				54E9281C1F33950B00C1953E /* FSTEventAccumulator.h */,
 				5492E0392021401F00B64F25 /* FSTEventAccumulator.mm */,
 				DE51B1881F0D48AC0013853F /* FSTHelpers.h */,
@@ -881,7 +884,6 @@
 				5491BC711FB44593008B3588 /* FSTIntegrationTestCase.mm */,
 				54E9282A1F339CAD00C1953E /* XCTestCase+Await.h */,
 				5492E0372021401E00B64F25 /* XCTestCase+Await.mm */,
-				7346E61C20325C6900FD6CEF /* FSTDispatchQueueTests.mm */,
 			);
 			path = Util;
 			sourceTree = "<group>";
@@ -889,6 +891,7 @@
 		DE51B1931F0D48AC0013853F /* SpecTests */ = {
 			isa = PBXGroup;
 			children = (
+				DE51B19C1F0D48AC0013853F /* json */,
 				5492E02C20213FFB00B64F25 /* FSTLevelDBSpecTests.mm */,
 				5492E02F20213FFC00B64F25 /* FSTMemorySpecTests.mm */,
 				DE51B1961F0D48AC0013853F /* FSTMockDatastore.h */,
@@ -897,7 +900,6 @@
 				5492E03020213FFC00B64F25 /* FSTSpecTests.mm */,
 				DE51B19A1F0D48AC0013853F /* FSTSyncEngineTestDriver.h */,
 				5492E02E20213FFC00B64F25 /* FSTSyncEngineTestDriver.mm */,
-				DE51B19C1F0D48AC0013853F /* json */,
 			);
 			path = SpecTests;
 			sourceTree = "<group>";
@@ -905,7 +907,7 @@
 		DE51B19C1F0D48AC0013853F /* json */ = {
 			isa = PBXGroup;
 			children = (
-				3B843E4A1F3930A400548890 /* remote_store_spec_test.json */,
+				DE51B1A71F0D48AC0013853F /* README.md */,
 				54DA129C1F315EE100DD57A1 /* collection_spec_test.json */,
 				54DA129D1F315EE100DD57A1 /* existence_filter_spec_test.json */,
 				54DA129E1F315EE100DD57A1 /* limbo_spec_test.json */,
@@ -914,9 +916,9 @@
 				54DA12A11F315EE100DD57A1 /* offline_spec_test.json */,
 				54DA12A21F315EE100DD57A1 /* orderby_spec_test.json */,
 				54DA12A31F315EE100DD57A1 /* persistence_spec_test.json */,
+				3B843E4A1F3930A400548890 /* remote_store_spec_test.json */,
 				54DA12A41F315EE100DD57A1 /* resume_token_spec_test.json */,
 				54DA12A51F315EE100DD57A1 /* write_spec_test.json */,
-				DE51B1A71F0D48AC0013853F /* README.md */,
 			);
 			path = json;
 			sourceTree = "<group>";
@@ -964,10 +966,10 @@
 			isa = PBXGroup;
 			children = (
 				73866A9F2082B069009BB4FF /* FIRArrayTransformTests.mm */,
-				6161B5012047140400A99DBB /* FIRFirestoreSourceTests.mm */,
 				5492E070202154D600B64F25 /* FIRCursorTests.mm */,
 				5492E06C202154D500B64F25 /* FIRDatabaseTests.mm */,
 				5492E06A202154D500B64F25 /* FIRFieldsTests.mm */,
+				6161B5012047140400A99DBB /* FIRFirestoreSourceTests.mm */,
 				5492E06B202154D500B64F25 /* FIRListenerRegistrationTests.mm */,
 				5492E069202154D500B64F25 /* FIRQueryTests.mm */,
 				5492E06E202154D600B64F25 /* FIRServerTimestampTests.mm */,
@@ -1148,9 +1150,9 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				6003F5A9195388D20070C39A /* Images.xcassets in Resources */,
 				873B8AEB1B1F5CCA007FD442 /* Main.storyboard in Resources */,
 				71719F9F1E33DC2100824A3D /* LaunchScreen.storyboard in Resources */,
-				6003F5A9195388D20070C39A /* Images.xcassets in Resources */,
 				6003F598195388D20070C39A /* InfoPlist.strings in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -1159,18 +1161,18 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				3B843E4C1F3A182900548890 /* remote_store_spec_test.json in Resources */,
+				6003F5BA195388D20070C39A /* InfoPlist.strings in Resources */,
+				54DA12A61F315EE100DD57A1 /* collection_spec_test.json in Resources */,
+				54DA12A71F315EE100DD57A1 /* existence_filter_spec_test.json in Resources */,
 				54DA12A81F315EE100DD57A1 /* limbo_spec_test.json in Resources */,
+				54DA12A91F315EE100DD57A1 /* limit_spec_test.json in Resources */,
 				54DA12AA1F315EE100DD57A1 /* listen_spec_test.json in Resources */,
-				54DA12A61F315EE100DD57A1 /* collection_spec_test.json in Resources */,
-				54DA12AE1F315EE100DD57A1 /* resume_token_spec_test.json in Resources */,
-				6003F5BA195388D20070C39A /* InfoPlist.strings in Resources */,
-				54DA12AF1F315EE100DD57A1 /* write_spec_test.json in Resources */,
-				54DA12AD1F315EE100DD57A1 /* persistence_spec_test.json in Resources */,
 				54DA12AB1F315EE100DD57A1 /* offline_spec_test.json in Resources */,
-				54DA12A71F315EE100DD57A1 /* existence_filter_spec_test.json in Resources */,
 				54DA12AC1F315EE100DD57A1 /* orderby_spec_test.json in Resources */,
-				54DA12A91F315EE100DD57A1 /* limit_spec_test.json in Resources */,
+				54DA12AD1F315EE100DD57A1 /* persistence_spec_test.json in Resources */,
+				3B843E4C1F3A182900548890 /* remote_store_spec_test.json in Resources */,
+				54DA12AE1F315EE100DD57A1 /* resume_token_spec_test.json in Resources */,
+				54DA12AF1F315EE100DD57A1 /* write_spec_test.json in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1178,8 +1180,8 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				DE03B2DD1F2149D600A30B9C /* InfoPlist.strings in Resources */,
 				DE03B3631F215E1A00A30B9C /* CAcert.pem in Resources */,
+				DE03B2DD1F2149D600A30B9C /* InfoPlist.strings in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1456,118 +1458,118 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				7346E61D20325C6900FD6CEF /* FSTDispatchQueueTests.mm in Sources */,
-				DE2EF0881F3D0B6E003D0CDC /* FSTTreeSortedDictionaryTests.m in Sources */,
-				ABE6637A201FA81900ED349A /* database_id_test.cc in Sources */,
-				5492E0AF2021552D00B64F25 /* FSTReferenceSetTests.mm in Sources */,
-				549CCA5120A36DBC00BCEB75 /* tree_sorted_map_test.cc in Sources */,
-				5492E09E2021552D00B64F25 /* FSTEagerGarbageCollectorTests.mm in Sources */,
-				5492E0C62021557E00B64F25 /* FSTWatchChange+Testing.mm in Sources */,
-				5492E064202154B900B64F25 /* FSTQueryListenerTests.mm in Sources */,
+				5492E050202154AA00B64F25 /* FIRCollectionReferenceTests.mm in Sources */,
+				5492E053202154AB00B64F25 /* FIRDocumentReferenceTests.mm in Sources */,
+				5492E055202154AB00B64F25 /* FIRDocumentSnapshotTests.mm in Sources */,
+				5492E056202154AB00B64F25 /* FIRFieldPathTests.mm in Sources */,
+				5492E054202154AB00B64F25 /* FIRFieldValueTests.mm in Sources */,
+				5467FB01203E5717009C9584 /* FIRFirestoreTests.mm in Sources */,
+				5492E052202154AB00B64F25 /* FIRGeoPointTests.mm in Sources */,
+				5492E059202154AB00B64F25 /* FIRQuerySnapshotTests.mm in Sources */,
+				5492E051202154AA00B64F25 /* FIRQueryTests.mm in Sources */,
+				5492E057202154AB00B64F25 /* FIRSnapshotMetadataTests.mm in Sources */,
 				B65D34A9203C995B0076A5E1 /* FIRTimestampTest.m in Sources */,
-				5492E03320213FFC00B64F25 /* FSTSyncEngineTestDriver.mm in Sources */,
-				AB380CFE201A2F4500D97691 /* string_util_test.cc in Sources */,
-				5492E0A42021552D00B64F25 /* FSTMemoryQueryCacheTests.mm in Sources */,
-				54C2294F1FECABAE007D065B /* log_test.cc in Sources */,
-				B686F2B22025000D0028D6BE /* resource_path_test.cc in Sources */,
-				5492E0CA2021557E00B64F25 /* FSTWatchChangeTests.mm in Sources */,
-				5492E063202154B900B64F25 /* FSTViewSnapshotTest.mm in Sources */,
-				54131E9720ADE679001DF3FF /* string_format_test.cc in Sources */,
 				5492E058202154AB00B64F25 /* FSTAPIHelpers.mm in Sources */,
-				AB380CFB2019388600D97691 /* target_id_generator_test.cc in Sources */,
-				5492E0A82021552D00B64F25 /* FSTLevelDBLocalStoreTests.mm in Sources */,
-				549CCA5920A36E1F00BCEB75 /* precondition_test.cc in Sources */,
-				ABC1D7DE2023A05300BA84F0 /* user_test.cc in Sources */,
-				5491BC721FB44593008B3588 /* FSTIntegrationTestCase.mm in Sources */,
-				ABC1D7DD2023A04F00BA84F0 /* empty_credentials_provider_test.cc in Sources */,
-				DE2EF0861F3D0B6E003D0CDC /* FSTImmutableSortedDictionary+Testing.m in Sources */,
-				B686F2AF2023DDEE0028D6BE /* field_path_test.cc in Sources */,
-				54A0352A20A3B3BD003E0143 /* testutil.cc in Sources */,
-				5492E03120213FFC00B64F25 /* FSTLevelDBSpecTests.mm in Sources */,
-				B6FB468F208F9BAE00554BA2 /* executor_std_test.cc in Sources */,
-				5492E0B12021552D00B64F25 /* FSTRemoteDocumentCacheTests.mm in Sources */,
+				DE2EF0851F3D0B6E003D0CDC /* FSTArraySortedDictionaryTests.m in Sources */,
+				5492E03D2021401F00B64F25 /* FSTAssertTests.mm in Sources */,
+				5492E0C82021557E00B64F25 /* FSTDatastoreTests.mm in Sources */,
+				7346E61D20325C6900FD6CEF /* FSTDispatchQueueTests.mm in Sources */,
+				5492E0B92021555100B64F25 /* FSTDocumentKeyTests.mm in Sources */,
 				5492E0BA2021555100B64F25 /* FSTDocumentSetTests.mm in Sources */,
-				54740A581FC914F000713A1A /* autoid_test.cc in Sources */,
-				5492E0A62021552D00B64F25 /* FSTPersistenceTestHelpers.mm in Sources */,
-				B6FB468E208F9BAB00554BA2 /* executor_libdispatch_test.mm in Sources */,
-				5467FB01203E5717009C9584 /* FIRFirestoreTests.mm in Sources */,
-				B6FB4684208EA0EC00554BA2 /* async_queue_libdispatch_test.mm in Sources */,
-				5492E0A12021552D00B64F25 /* FSTMemoryLocalStoreTests.mm in Sources */,
+				5492E0BD2021555100B64F25 /* FSTDocumentTests.mm in Sources */,
+				5492E09E2021552D00B64F25 /* FSTEagerGarbageCollectorTests.mm in Sources */,
+				5492E03E2021401F00B64F25 /* FSTEventAccumulator.mm in Sources */,
 				5492E067202154B900B64F25 /* FSTEventManagerTests.mm in Sources */,
-				54A0353020A3B3D8003E0143 /* statusor_test.cc in Sources */,
 				5492E0BF2021555100B64F25 /* FSTFieldValueTests.mm in Sources */,
-				54A0352620A3AED0003E0143 /* field_transform_test.mm in Sources */,
-				5492E055202154AB00B64F25 /* FIRDocumentSnapshotTests.mm in Sources */,
-				5492E03E2021401F00B64F25 /* FSTEventAccumulator.mm in Sources */,
-				54A0352720A3AED0003E0143 /* transform_operations_test.mm in Sources */,
-				DE2EF0851F3D0B6E003D0CDC /* FSTArraySortedDictionaryTests.m in Sources */,
-				5492E0AA2021552D00B64F25 /* FSTLevelDBRemoteDocumentCacheTests.mm in Sources */,
-				5492E0AC2021552D00B64F25 /* FSTMutationQueueTests.mm in Sources */,
-				5492E056202154AB00B64F25 /* FIRFieldPathTests.mm in Sources */,
-				5492E03220213FFC00B64F25 /* FSTMockDatastore.mm in Sources */,
-				ABC1D7E12023A40C00BA84F0 /* token_test.cc in Sources */,
-				54A0353520A3D8CB003E0143 /* iterator_adaptors_test.cc in Sources */,
-				AB356EF7200EA5EB0089B766 /* field_value_test.cc in Sources */,
-				AB7BAB342012B519001E0872 /* geo_point_test.cc in Sources */,
-				5492E0AD2021552D00B64F25 /* FSTMemoryMutationQueueTests.mm in Sources */,
-				5492E051202154AA00B64F25 /* FIRQueryTests.mm in Sources */,
-				5492E054202154AB00B64F25 /* FIRFieldValueTests.mm in Sources */,
-				AB6B908620322E6D00CC290A /* maybe_document_test.cc in Sources */,
+				54764FAF1FAA21B90085E60A /* FSTGoogleTestTests.mm in Sources */,
+				5492E03F2021401F00B64F25 /* FSTHelpers.mm in Sources */,
+				DE2EF0861F3D0B6E003D0CDC /* FSTImmutableSortedDictionary+Testing.m in Sources */,
+				DE2EF0871F3D0B6E003D0CDC /* FSTImmutableSortedSet+Testing.m in Sources */,
+				5491BC721FB44593008B3588 /* FSTIntegrationTestCase.mm in Sources */,
+				5492E0A72021552D00B64F25 /* FSTLevelDBKeyTests.mm in Sources */,
+				5492E0A82021552D00B64F25 /* FSTLevelDBLocalStoreTests.mm in Sources */,
 				5492E09F2021552D00B64F25 /* FSTLevelDBMigrationsTests.mm in Sources */,
-				546854AA20A36867004BDBD5 /* datastore_test.cc in Sources */,
-				5492E053202154AB00B64F25 /* FIRDocumentReferenceTests.mm in Sources */,
-				5492E09D2021552D00B64F25 /* FSTLocalStoreTests.mm in Sources */,
+				5492E0A02021552D00B64F25 /* FSTLevelDBMutationQueueTests.mm in Sources */,
+				5492E0AE2021552D00B64F25 /* FSTLevelDBQueryCacheTests.mm in Sources */,
+				5492E0AA2021552D00B64F25 /* FSTLevelDBRemoteDocumentCacheTests.mm in Sources */,
+				5492E03120213FFC00B64F25 /* FSTLevelDBSpecTests.mm in Sources */,
+				132E3E53179DE287D875F3F2 /* FSTLevelDBTransactionTests.mm in Sources */,
 				5492E0A32021552D00B64F25 /* FSTLocalSerializerTests.mm in Sources */,
-				5492E0A72021552D00B64F25 /* FSTLevelDBKeyTests.mm in Sources */,
-				B6FB4685208EA0F000554BA2 /* async_queue_std_test.cc in Sources */,
-				5492E0A22021552D00B64F25 /* FSTQueryCacheTests.mm in Sources */,
+				5492E09D2021552D00B64F25 /* FSTLocalStoreTests.mm in Sources */,
+				5492E0A12021552D00B64F25 /* FSTMemoryLocalStoreTests.mm in Sources */,
+				5492E0AD2021552D00B64F25 /* FSTMemoryMutationQueueTests.mm in Sources */,
+				5492E0A42021552D00B64F25 /* FSTMemoryQueryCacheTests.mm in Sources */,
 				5492E0A52021552D00B64F25 /* FSTMemoryRemoteDocumentCacheTests.mm in Sources */,
-				AB6B908820322E8800CC290A /* no_document_test.cc in Sources */,
-				5492E0BD2021555100B64F25 /* FSTDocumentTests.mm in Sources */,
-				5492E0B92021555100B64F25 /* FSTDocumentKeyTests.mm in Sources */,
-				DE2EF0871F3D0B6E003D0CDC /* FSTImmutableSortedSet+Testing.m in Sources */,
-				5492E0C82021557E00B64F25 /* FSTDatastoreTests.mm in Sources */,
-				54995F6F205B6E12004EFFA0 /* leveldb_key_test.cc in Sources */,
+				5492E03420213FFC00B64F25 /* FSTMemorySpecTests.mm in Sources */,
+				5492E03220213FFC00B64F25 /* FSTMockDatastore.mm in Sources */,
+				5492E0AC2021552D00B64F25 /* FSTMutationQueueTests.mm in Sources */,
+				5492E0BE2021555100B64F25 /* FSTMutationTests.mm in Sources */,
+				5492E0A62021552D00B64F25 /* FSTPersistenceTestHelpers.mm in Sources */,
+				5492E0A22021552D00B64F25 /* FSTQueryCacheTests.mm in Sources */,
+				5492E064202154B900B64F25 /* FSTQueryListenerTests.mm in Sources */,
+				5492E068202154B900B64F25 /* FSTQueryTests.mm in Sources */,
+				5492E0AF2021552D00B64F25 /* FSTReferenceSetTests.mm in Sources */,
+				5492E0B12021552D00B64F25 /* FSTRemoteDocumentCacheTests.mm in Sources */,
+				5492E0C92021557E00B64F25 /* FSTRemoteEventTests.mm in Sources */,
+				5492E0C72021557E00B64F25 /* FSTSerializerBetaTests.mm in Sources */,
+				5492E03520213FFC00B64F25 /* FSTSpecTests.mm in Sources */,
+				5492E03320213FFC00B64F25 /* FSTSyncEngineTestDriver.mm in Sources */,
+				DE2EF0881F3D0B6E003D0CDC /* FSTTreeSortedDictionaryTests.m in Sources */,
+				5492E063202154B900B64F25 /* FSTViewSnapshotTest.mm in Sources */,
 				5492E065202154B900B64F25 /* FSTViewTests.mm in Sources */,
-				B6FB467D208E9D3C00554BA2 /* async_queue_test.cc in Sources */,
-				54A0352F20A3B3D8003E0143 /* status_test.cc in Sources */,
+				5492E0C62021557E00B64F25 /* FSTWatchChange+Testing.mm in Sources */,
+				5492E0CA2021557E00B64F25 /* FSTWatchChangeTests.mm in Sources */,
+				5492E0AB2021552D00B64F25 /* StringViewTests.mm in Sources */,
 				5492E03C2021401F00B64F25 /* XCTestCase+Await.mm in Sources */,
-				B6152AD7202A53CB000E5744 /* document_key_test.cc in Sources */,
 				5467FB08203E6A44009C9584 /* app_testing.mm in Sources */,
-				54764FAF1FAA21B90085E60A /* FSTGoogleTestTests.mm in Sources */,
-				AB380D04201BC6E400D97691 /* ordered_code_test.cc in Sources */,
-				5492E03F2021401F00B64F25 /* FSTHelpers.mm in Sources */,
-				549CCA5220A36DBC00BCEB75 /* sorted_map_test.cc in Sources */,
-				5492E068202154B900B64F25 /* FSTQueryTests.mm in Sources */,
-				5492E0AB2021552D00B64F25 /* StringViewTests.mm in Sources */,
-				5492E0C92021557E00B64F25 /* FSTRemoteEventTests.mm in Sources */,
-				ABC1D7E42024AFDE00BA84F0 /* firebase_credentials_provider_test.mm in Sources */,
-				AB6B908420322E4D00CC290A /* document_test.cc in Sources */,
-				ABF6506C201131F8005F2C74 /* timestamp_test.cc in Sources */,
-				5492E0AE2021552D00B64F25 /* FSTLevelDBQueryCacheTests.mm in Sources */,
-				ABC1D7DC2023A04B00BA84F0 /* credentials_provider_test.cc in Sources */,
-				54511E8E209805F8005BD28F /* hashing_test.cc in Sources */,
-				5492E059202154AB00B64F25 /* FIRQuerySnapshotTests.mm in Sources */,
-				5492E050202154AA00B64F25 /* FIRCollectionReferenceTests.mm in Sources */,
-				ABA495BB202B7E80008A7851 /* snapshot_version_test.cc in Sources */,
-				5492E0A02021552D00B64F25 /* FSTLevelDBMutationQueueTests.mm in Sources */,
 				54EB764D202277B30088B8F3 /* array_sorted_map_test.cc in Sources */,
-				54131E9920AE076D001DF3FF /* hard_assert_test.cc in Sources */,
-				5492E03420213FFC00B64F25 /* FSTMemorySpecTests.mm in Sources */,
+				B6FB4684208EA0EC00554BA2 /* async_queue_libdispatch_test.mm in Sources */,
+				B6FB4685208EA0F000554BA2 /* async_queue_std_test.cc in Sources */,
+				B6FB467D208E9D3C00554BA2 /* async_queue_test.cc in Sources */,
+				54740A581FC914F000713A1A /* autoid_test.cc in Sources */,
 				AB380D02201BC69F00D97691 /* bits_test.cc in Sources */,
 				548DB929200D59F600E00ABC /* comparison_test.cc in Sources */,
-				549CCA5720A36E1F00BCEB75 /* field_mask_test.cc in Sources */,
-				5492E03D2021401F00B64F25 /* FSTAssertTests.mm in Sources */,
+				ABC1D7DC2023A04B00BA84F0 /* credentials_provider_test.cc in Sources */,
+				ABE6637A201FA81900ED349A /* database_id_test.cc in Sources */,
 				AB38D93020236E21000A432D /* database_info_test.cc in Sources */,
-				5492E052202154AB00B64F25 /* FIRGeoPointTests.mm in Sources */,
-				5492E0C72021557E00B64F25 /* FSTSerializerBetaTests.mm in Sources */,
+				546854AA20A36867004BDBD5 /* datastore_test.cc in Sources */,
+				B6152AD7202A53CB000E5744 /* document_key_test.cc in Sources */,
+				AB6B908420322E4D00CC290A /* document_test.cc in Sources */,
+				ABC1D7DD2023A04F00BA84F0 /* empty_credentials_provider_test.cc in Sources */,
+				B6FB468E208F9BAB00554BA2 /* executor_libdispatch_test.mm in Sources */,
+				B6FB468F208F9BAE00554BA2 /* executor_std_test.cc in Sources */,
 				B6FB4690208F9BB300554BA2 /* executor_test.cc in Sources */,
-				5492E03520213FFC00B64F25 /* FSTSpecTests.mm in Sources */,
-				5492E057202154AB00B64F25 /* FIRSnapshotMetadataTests.mm in Sources */,
+				549CCA5720A36E1F00BCEB75 /* field_mask_test.cc in Sources */,
+				B686F2AF2023DDEE0028D6BE /* field_path_test.cc in Sources */,
+				54A0352620A3AED0003E0143 /* field_transform_test.mm in Sources */,
+				AB356EF7200EA5EB0089B766 /* field_value_test.cc in Sources */,
+				ABC1D7E42024AFDE00BA84F0 /* firebase_credentials_provider_test.mm in Sources */,
+				AB7BAB342012B519001E0872 /* geo_point_test.cc in Sources */,
+				73FE5066020EF9B2892C86BF /* hard_assert_test.cc in Sources */,
+				54511E8E209805F8005BD28F /* hashing_test.cc in Sources */,
+				54A0353520A3D8CB003E0143 /* iterator_adaptors_test.cc in Sources */,
+				54995F6F205B6E12004EFFA0 /* leveldb_key_test.cc in Sources */,
+				54C2294F1FECABAE007D065B /* log_test.cc in Sources */,
+				AB6B908620322E6D00CC290A /* maybe_document_test.cc in Sources */,
+				AB6B908820322E8800CC290A /* no_document_test.cc in Sources */,
+				AB380D04201BC6E400D97691 /* ordered_code_test.cc in Sources */,
+				549CCA5920A36E1F00BCEB75 /* precondition_test.cc in Sources */,
+				B686F2B22025000D0028D6BE /* resource_path_test.cc in Sources */,
 				54740A571FC914BA00713A1A /* secure_random_test.cc in Sources */,
+				ABA495BB202B7E80008A7851 /* snapshot_version_test.cc in Sources */,
+				549CCA5220A36DBC00BCEB75 /* sorted_map_test.cc in Sources */,
 				549CCA5020A36DBC00BCEB75 /* sorted_set_test.cc in Sources */,
-				5492E0BE2021555100B64F25 /* FSTMutationTests.mm in Sources */,
-				132E3E53179DE287D875F3F2 /* FSTLevelDBTransactionTests.mm in Sources */,
+				54A0352F20A3B3D8003E0143 /* status_test.cc in Sources */,
+				54A0353020A3B3D8003E0143 /* statusor_test.cc in Sources */,
+				54131E9720ADE679001DF3FF /* string_format_test.cc in Sources */,
+				AB380CFE201A2F4500D97691 /* string_util_test.cc in Sources */,
+				AB380CFB2019388600D97691 /* target_id_generator_test.cc in Sources */,
+				54A0352A20A3B3BD003E0143 /* testutil.cc in Sources */,
+				ABF6506C201131F8005F2C74 /* timestamp_test.cc in Sources */,
+				ABC1D7E12023A40C00BA84F0 /* token_test.cc in Sources */,
+				54A0352720A3AED0003E0143 /* transform_operations_test.mm in Sources */,
+				549CCA5120A36DBC00BCEB75 /* tree_sorted_map_test.cc in Sources */,
+				ABC1D7DE2023A05300BA84F0 /* user_test.cc in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1576,24 +1578,24 @@
 			buildActionMask = 2147483647;
 			files = (
 				73866AA12082B0A5009BB4FF /* FIRArrayTransformTests.mm in Sources */,
+				5492E079202154D600B64F25 /* FIRCursorTests.mm in Sources */,
+				5492E075202154D600B64F25 /* FIRDatabaseTests.mm in Sources */,
+				5492E073202154D600B64F25 /* FIRFieldsTests.mm in Sources */,
 				6161B5032047140C00A99DBB /* FIRFirestoreSourceTests.mm in Sources */,
-				5492E076202154D600B64F25 /* FIRValidationTests.mm in Sources */,
+				5492E074202154D600B64F25 /* FIRListenerRegistrationTests.mm in Sources */,
 				5492E072202154D600B64F25 /* FIRQueryTests.mm in Sources */,
-				5491BC731FB44593008B3588 /* FSTIntegrationTestCase.mm in Sources */,
-				5492E0442021457E00B64F25 /* XCTestCase+Await.mm in Sources */,
+				5492E077202154D600B64F25 /* FIRServerTimestampTests.mm in Sources */,
 				5492E07A202154D600B64F25 /* FIRTypeTests.mm in Sources */,
-				5492E0422021440500B64F25 /* FSTHelpers.mm in Sources */,
+				5492E076202154D600B64F25 /* FIRValidationTests.mm in Sources */,
+				5492E078202154D600B64F25 /* FIRWriteBatchTests.mm in Sources */,
+				5492E082202154EC00B64F25 /* FSTDatastoreTests.mm in Sources */,
 				5492E041202143E700B64F25 /* FSTEventAccumulator.mm in Sources */,
+				5492E0422021440500B64F25 /* FSTHelpers.mm in Sources */,
+				5491BC731FB44593008B3588 /* FSTIntegrationTestCase.mm in Sources */,
 				5492E080202154EC00B64F25 /* FSTSmokeTests.mm in Sources */,
-				5492E077202154D600B64F25 /* FIRServerTimestampTests.mm in Sources */,
 				5492E081202154EC00B64F25 /* FSTStreamTests.mm in Sources */,
-				5492E074202154D600B64F25 /* FIRListenerRegistrationTests.mm in Sources */,
-				5492E082202154EC00B64F25 /* FSTDatastoreTests.mm in Sources */,
-				5492E079202154D600B64F25 /* FIRCursorTests.mm in Sources */,
-				5492E073202154D600B64F25 /* FIRFieldsTests.mm in Sources */,
 				5492E07F202154EC00B64F25 /* FSTTransactionTests.mm in Sources */,
-				5492E075202154D600B64F25 /* FIRDatabaseTests.mm in Sources */,
-				5492E078202154D600B64F25 /* FIRWriteBatchTests.mm in Sources */,
+				5492E0442021457E00B64F25 /* XCTestCase+Await.mm in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/scripts/check_copyright.sh b/scripts/check_copyright.sh
index 5cd8a18..cc83e29 100755
--- a/scripts/check_copyright.sh
+++ b/scripts/check_copyright.sh
@@ -22,7 +22,7 @@ options=(
 )
 
 git grep "${options[@]}" \
-    -- '*.'{c,cc,h,js,m,mm,py,sh,swift} \
+    -- '*.'{c,cc,h,js,m,mm,py,rb,sh,swift} \
     ':(exclude)**/third_party/**'
 if [[ $? == 0 ]]; then
   echo "ERROR: Missing copyright notices in the files above. Please fix."
diff --git a/scripts/sync_project.rb b/scripts/sync_project.rb
new file mode 100755
index 0000000..e34ae31
--- /dev/null
+++ b/scripts/sync_project.rb
@@ -0,0 +1,569 @@
+#!/usr/bin/ruby
+
+# Copyright 2018 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.
+
+# Syncs Xcode project folder and target structure with the filesystem. This
+# script finds all files on the filesystem that match the patterns supplied
+# below and changes the project to match what it found.
+#
+# Run this script after adding/removing tests to keep the project in sync.
+
+require 'pathname'
+
+# Note that xcodeproj 1.5.8 appears to be broken
+# https://github.com/CocoaPods/Xcodeproj/issues/572
+gem 'xcodeproj', '!= 1.5.8'
+require 'xcodeproj'
+
+
+def main()
+  # Make all filenames relative to the project root.
+  Dir.chdir(File.join(File.dirname(__FILE__), '..'))
+
+  sync_firestore()
+end
+
+
+def sync_firestore()
+  project = Xcodeproj::Project.open('Firestore/Example/Firestore.xcodeproj')
+
+  # Enable warnings after opening the project to avoid the warnings in
+  # xcodeproj itself
+  $VERBOSE = true
+
+  s = Syncer.new(project, Dir.pwd)
+
+  # Files on the filesystem that should be ignored.
+  s.ignore_files = [
+    'CMakeLists.txt',
+    'InfoPlist.strings',
+    '*.plist',
+
+    # b/79496027
+    'Firestore/core/test/firebase/firestore/remote/serializer_test.cc',
+  ]
+
+  # Folder groups in the Xcode project that contain tests.
+  s.test_groups = [
+    'Tests',
+    'CoreTests',
+    'SwiftTests',
+  ]
+
+  s.target 'Firestore_Tests_iOS' do |t|
+    t.source_files = [
+      'Firestore/Example/Tests/**',
+      'Firestore/core/test/**',
+      'Firestore/third_party/Immutable/Tests/**',
+    ]
+    t.exclude_files = [
+      # needs to be in project but not in target
+      'Firestore/Example/Tests/Tests-Info.plist',
+
+      # These files are integration tests, handled below
+      'Firestore/Example/Tests/Integration/**',
+    ]
+  end
+
+  s.target 'Firestore_IntegrationTests_iOS' do |t|
+    t.source_files = [
+      'Firestore/Example/Tests/Integration/**',
+      'Firestore/Example/Tests/Util/FSTEventAccumulator.mm',
+      'Firestore/Example/Tests/Util/FSTHelpers.mm',
+      'Firestore/Example/Tests/Util/FSTIntegrationTestCase.mm',
+      'Firestore/Example/Tests/Util/XCTestCase+Await.mm',
+      'Firestore/Example/Tests/en.lproj/InfoPlist.strings',
+    ]
+  end
+
+  s.sync()
+  sort_project(project)
+  if project.dirty?
+    project.save()
+  end
+end
+
+
+# The definition of a test target including the target name, its source_files
+# and exclude_files. A file is considered part of a target if it matches a
+# pattern in source_files but does not match a pattern in exclude_files.
+class TargetDef
+  def initialize(name)
+    @name = name
+    @source_files = []
+    @exclude_files = []
+  end
+
+  attr_accessor :name, :source_files, :exclude_files
+
+  # Returns true if the given relative_path matches this target's source_files
+  # but not its exclude_files.
+  #
+  # Args:
+  # - relative_path: a Pathname instance with a path relative to the project
+  #   root.
+  def matches?(relative_path)
+    return matches_patterns(relative_path, @source_files) &&
+      !matches_patterns(relative_path, @exclude_files)
+  end
+
+  private
+  # Evaluates the relative_path against the given list of fnmatch patterns.
+  def matches_patterns(relative_path, patterns)
+    patterns.each do |pattern|
+      if relative_path.fnmatch?(pattern)
+        return true
+      end
+    end
+    return false
+  end
+end
+
+
+class Syncer
+  def initialize(project, root_dir)
+    @project = project
+    @root_dir = Pathname.new(root_dir)
+
+    @finder = DirectoryLister.new(@root_dir)
+
+    @seen_groups = {}
+
+    @test_groups = []
+    @targets = []
+  end
+
+  # Considers the given fnmatch glob patterns to be ignored by the syncer.
+  # Patterns are matched both against the basename and project-relative
+  # qualified pathname.
+  def ignore_files=(patterns)
+    @finder.add_patterns(patterns)
+  end
+
+  # Names the groups within the project that serve as roots for tests within
+  # the project.
+  def test_groups=(groups)
+    @test_groups = []
+    groups.each do |group|
+      project_group = @project[group]
+      if project_group.nil?
+        raise "Project does not contain group #{group}"
+      end
+      @test_groups.push(@project[group])
+    end
+  end
+
+  # Starts a new target block. Creates a new TargetDef and yields it.
+  def target(name, &block)
+    t = TargetDef.new(name)
+    @targets.push(t)
+
+    block.call(t)
+  end
+
+  # Synchronizes the filesystem with the project.
+  #
+  # Generally there are three separate ways a file is referenced within a project:
+  #
+  #  1. The file must be in the global list of files, assigning it a UUID.
+  #  2. The file must be added to folder groups, describing where it is in the
+  #     folder view of the Project Navigator.
+  #  3. The file must be added to a target descrbing how it's built.
+  #
+  # The Xcodeproj library handles (1) for us automatically if we do (2).
+  #
+  # Synchronization essentially proceeds in two steps:
+  #
+  #  1. Sync the filesystem structure with the folder group structure. This has
+  #     the effect of bringing (1) and (2) into sync.
+  #  2. Sync the global list of files with the targets.
+  def sync()
+    group_differ = GroupDiffer.new(@finder)
+    group_diffs = group_differ.diff(@test_groups)
+    sync_groups(group_diffs)
+
+    @targets.each do |target_def|
+      sync_target(target_def)
+    end
+  end
+
+  private
+  def sync_groups(diff_entries)
+    diff_entries.each do |entry|
+      if !entry.in_source && entry.in_target
+        remove_from_project(entry.ref)
+      end
+
+      if entry.in_source && !entry.in_target
+        add_to_project(entry.path)
+      end
+    end
+  end
+
+  # Removes the given file reference from the project after the file is found
+  # missing but references to it still exist in the project.
+  def remove_from_project(file_ref)
+    group = file_ref.parents[-1]
+
+    mark_change_in_group(relative_path(group))
+    puts "  #{basename(file_ref)} - removed"
+
+    # If the file is gone, any build phase that refers to must also remove the
+    # file. Without this, the project will have build file references that
+    # contain no actual file.
+    @project.native_targets.each do |target|
+      target.build_phases.each do |phase|
+        if phase.include?(file_ref)
+          phase.remove_file_reference(file_ref)
+        end
+      end
+    end
+
+    file_ref.remove_from_project
+  end
+
+  # Adds the given file to the project, in a path starting from the test root
+  # that fully prefixes the file.
+  def add_to_project(path)
+    root_group = find_test_group_containing(path)
+
+    # Find or create the group to contain the path.
+    dir_rel_path = path.relative_path_from(root_group.real_path).dirname
+    group = root_group.find_subpath(dir_rel_path.to_s, true)
+
+    mark_change_in_group(relative_path(group))
+
+    file_ref = group.new_file(path.to_s)
+
+    puts "  #{basename(file_ref)} - added"
+    return file_ref
+  end
+
+  # Finds a test group whose path prefixes the given entry. Starting from the
+  # project root may not work since not all test directories exist within the
+  # example app.
+  def find_test_group_containing(path)
+    @test_groups.each do |group|
+      rel = path.relative_path_from(group.real_path)
+      next if rel.to_s.start_with?('..')
+
+      return group
+    end
+
+    raise "Could not find an existing test group that's a parent of #{entry.path}"
+  end
+
+  def mark_change_in_group(group)
+    path = group.to_s
+    if !@seen_groups.has_key?(path)
+      puts "#{path} ..."
+      @seen_groups[path] = true
+    end
+  end
+
+  SOURCES = %w{.c .cc .m .mm}
+
+  def sync_target(target_def)
+    target = @project.native_targets.find { |t| t.name == target_def.name }
+    if !target
+      raise "Missing target #{target_def.name}"
+    end
+
+    files = find_files_for_target(target_def)
+    sources, resources = classify_files(files)
+
+    sync_build_phase(target, target.source_build_phase, sources)
+  end
+
+  def classify_files(files)
+    sources = {}
+    resources = {}
+
+    files.each do |file|
+      path = file.real_path
+      ext = path.extname
+      if SOURCES.include?(ext)
+        sources[path] = file
+      end
+    end
+
+    return sources, resources
+  end
+
+  def sync_build_phase(target, phase, sources)
+    # buffer changes to the phase to avoid modifying the array we're iterating
+    # over.
+    to_remove = []
+    phase.files.each do |build_file|
+      source_path = build_file.file_ref.real_path
+      if sources.has_key?(source_path)
+        # matches spec and existing target no action taken
+        sources.delete(source_path)
+
+      else
+        # in the phase but now missing in the groups
+        to_remove.push(build_file)
+      end
+    end
+
+    to_remove.each do |build_file|
+      mark_change_in_group(target.name)
+
+      source_path = build_file.file_ref.real_path
+      puts "  #{relative_path(source_path)} - removed"
+      phase.remove_build_file(build_file)
+    end
+
+    sources.each do |path, file_ref|
+      mark_change_in_group(target.name)
+
+      phase.add_file_reference(file_ref)
+      puts "  #{relative_path(file_ref)} - added"
+    end
+  end
+
+  def find_files_for_target(target_def)
+    result = []
+
+    @project.files.each do |file_ref|
+      next if file_ref.source_tree != '<group>'
+
+      rel = relative_path(file_ref)
+      if target_def.matches?(rel)
+        result.push(file_ref)
+      end
+    end
+    return result
+  end
+
+  def normalize_to_pathname(file_ref)
+    if !file_ref.is_a? Pathname
+      if file_ref.is_a? String
+        file_ref = Pathname.new(file_ref)
+      else
+        file_ref = file_ref.real_path
+      end
+    end
+    return file_ref
+  end
+
+  def basename(file_ref)
+    return normalize_to_pathname(file_ref).basename
+  end
+
+  def relative_path(file_ref)
+    file_ref = normalize_to_pathname(file_ref)
+    return file_ref.relative_path_from(@root_dir)
+  end
+end
+
+
+def sort_project(project)
+  project.groups.each do |group|
+    sort_group(group)
+  end
+
+  project.targets.each do |target|
+    target.build_phases.each do |phase|
+      phase.files.sort! { |a, b|
+        a.file_ref.real_path.basename <=> b.file_ref.real_path.basename
+      }
+    end
+  end
+end
+
+
+def sort_group(group)
+  group.groups.each do |child|
+    sort_group(child)
+  end
+
+  group.children.sort! do |a, b|
+    # Sort groups first
+    if a.isa == 'PBXGroup' && b.isa != 'PBXGroup'
+      -1
+    elsif a.isa != 'PBXGroup' && b.isa == 'PBXGroup'
+      1
+    elsif a.display_name && b.display_name
+      File.basename(a.display_name) <=> File.basename(b.display_name)
+    else
+      0
+    end
+  end
+end
+
+
+# Tracks how a file is referenced: in the project file, on the filesystem,
+# neither, or both.
+class DiffEntry
+  def initialize(path)
+    @path = path
+    @in_source = false
+    @in_target = false
+    @ref = nil
+  end
+
+  attr_reader :path
+  attr_accessor :in_source, :in_target, :ref
+end
+
+
+# Diffs folder groups against the filesystem directories referenced by those
+# folder groups.
+#
+# This performs the diff starting from the directories referenced by the test
+# groups in the project, finding files contained within them. When comparing
+# the files it finds against the project this acts on absolute paths to avoid
+# problems with arbitary additional groupings in project structure that are
+# standard, e.g. "Supporting Files" or "en.lproj" which either act as aliases
+# for the parent or are folders that are omitted from the project view.
+# Processing the diff this way allows these warts to be tolerated, even if they
+# won't necessarily be recreated if an artifact is added to the filesystem.
+class GroupDiffer
+  def initialize(dir_lister)
+    @dir_lister = dir_lister
+
+    @entries = {}
+    @dirs = {}
+  end
+
+  # Finds all tests on the filesystem contained within the paths of the given
+  # test groups and computes a list of DiffEntries describing the state of the
+  # files.
+  #
+  # Args:
+  # - groups: A list of PBXGroup objects representing folder groups within the
+  #   project that contain tests.
+  #
+  # Returns:
+  # A list of DiffEntry objects, one for each test found. If the test exists on
+  # the filesystem, :in_source will be true. If the test exists in the project
+  # :in_target will be true and :ref will be set to the PBXFileReference naming
+  # the file.
+  def diff(groups) groups.each do |group| diff_project_files(group) end
+
+    return @entries.values.sort { |a, b| a.path.basename <=> b.path.basename }
+  end
+
+  private
+  # Recursively traverses all the folder groups in the Xcode project and finds
+  # files both on the filesystem and the group file listing.
+  def diff_project_files(group)
+    find_fs_files(group.real_path)
+
+    group.groups.each do |child|
+      diff_project_files(child)
+    end
+
+    group.files.each do |file_ref|
+      path = file_ref.real_path
+      entry = track_file(path)
+      entry.in_target = true
+      entry.ref = file_ref
+
+      if path.file?
+        entry.in_source = true
+      end
+    end
+  end
+
+  def find_fs_files(parent_path)
+    # Avoid re-traversing the filesystem
+    if @dirs.has_key?(parent_path)
+      return
+    end
+    @dirs[parent_path] = true
+
+    @dir_lister.entries(parent_path).each do |path|
+      if path.directory?
+        find_fs_files(path)
+        next
+      end
+
+      entry = track_file(path)
+      entry.in_source = true
+    end
+  end
+
+  def track_file(path)
+    if @entries.has_key?(path)
+      return @entries[path]
+    end
+
+    entry = DiffEntry.new(path)
+    @entries[path] = entry
+    return entry
+  end
+end
+
+
+# Finds files on the filesystem while ignoring files that have been declared to
+# be ignored.
+class DirectoryLister
+  def initialize(root_dir)
+    @root_dir = root_dir
+    @ignore_basenames = ['.', '..']
+    @ignore_pathnames = []
+  end
+
+  def add_patterns(patterns)
+    patterns.each do |pattern|
+      if File.basename(pattern) != pattern
+        @ignore_pathnames.push(File.join(@root_dir, pattern))
+      else
+        @ignore_basenames.push(pattern)
+      end
+    end
+  end
+
+  # Finds filesystem entries that are immediate children of the given Pathname,
+  # ignoring files that match the the global ignore_files patterns.
+  def entries(path)
+    result = []
+    path.entries.each do |entry|
+      next if ignore_basename?(entry)
+
+      file = path.join(entry)
+      next if ignore_pathname?(file)
+
+      result.push(file)
+    end
+    return result
+  end
+
+  private
+  def ignore_basename?(basename)
+    @ignore_basenames.each do |ignore|
+      if basename.fnmatch(ignore)
+        return true
+      end
+    end
+    return false
+  end
+
+  def ignore_pathname?(file)
+    @ignore_pathnames.each do |ignore|
+      if file.fnmatch(ignore)
+        return true
+      end
+    end
+    return false
+  end
+end
+
+
+if __FILE__ == $0
+  main()
+end