Add a new Xcode target and scheme for fuzz tests (#1364)

Created `Firestore_FuzzTests_iOS` Xcode target as a duplicate of the target
  `Firestore_Tests_iOS`.
    - Added `-fsanitize-coverage=trace-pc-guard` to the compiler flags to enable
      code coverage by libFuzzer fuzzing driver.
    - Modified the files to compile to the fuzz testing ones.
    - Added a Principal testing class.
* Modified the `Podfile` to include `LibFuzzer.podspec` as a dependency for
  the target `Firestore_FuzzTests_iOS`.
* Added a skeleton for fuzz testing. Currently does not test any code but
  the fuzzing works fine and calls an empty `LLVMFuzzerTestOneInput`
  with different input values.
    - This means that fuzzing does not finish or crash.

5 files changed, 345 insertions, 2 deletions

diff --git a/Firestore/Example/Firestore.xcodeproj/project.pbxproj b/Firestore/Example/Firestore.xcodeproj/project.pbxproj
index 9207ad2..b366cb9 100644
--- a/Firestore/Example/Firestore.xcodeproj/project.pbxproj
+++ b/Firestore/Example/Firestore.xcodeproj/project.pbxproj
@@ -145,6 +145,10 @@
 		6003F5B2195388D20070C39A /* UIKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F591195388D20070C39A /* UIKit.framework */; };
 		6003F5BA195388D20070C39A /* InfoPlist.strings in Resources */ = {isa = PBXBuildFile; fileRef = 6003F5B8195388D20070C39A /* InfoPlist.strings */; };
 		6161B5032047140C00A99DBB /* FIRFirestoreSourceTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 6161B5012047140400A99DBB /* FIRFirestoreSourceTests.mm */; };
+		6EDD3B4620BF247500C33877 /* Foundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F58D195388D20070C39A /* Foundation.framework */; };
+		6EDD3B4820BF247500C33877 /* UIKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F591195388D20070C39A /* UIKit.framework */; };
+		6EDD3B4920BF247500C33877 /* XCTest.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F5AF195388D20070C39A /* XCTest.framework */; };
+		6EDD3B6020BF25AE00C33877 /* FSTFuzzTestsPrincipal.mm in Sources */ = {isa = PBXBuildFile; fileRef = 6EDD3B5E20BF24D000C33877 /* FSTFuzzTestsPrincipal.mm */; };
 		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 */; };
@@ -181,6 +185,7 @@
 		B6FB4690208F9BB300554BA2 /* executor_test.cc in Sources */ = {isa = PBXBuildFile; fileRef = B6FB4688208F9B9100554BA2 /* executor_test.cc */; };
 		BF219E98F1C5A1DAEB5EEC86 /* Pods_Firestore_Example_iOS_SwiftBuildTest.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 379B34A1536045869826D82A /* Pods_Firestore_Example_iOS_SwiftBuildTest.framework */; };
 		C1AA536F90A0A576CA2816EB /* Pods_Firestore_Example_iOS_Firestore_SwiftTests_iOS.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = BB92EB03E3F92485023F64ED /* Pods_Firestore_Example_iOS_Firestore_SwiftTests_iOS.framework */; };
+		C482E724F4B10968417C3F78 /* Pods_Firestore_FuzzTests_iOS.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B79CA87A1A01FC5329031C9B /* Pods_Firestore_FuzzTests_iOS.framework */; };
 		C80B10E79CDD7EF7843C321E /* type_traits_apple_test.mm in Sources */ = {isa = PBXBuildFile; fileRef = 2A0CF41BA5AED6049B0BEB2C /* type_traits_apple_test.mm */; };
 		C8D3CE2343E53223E6487F2C /* Pods_Firestore_Example_iOS.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 5918805E993304321A05E82B /* Pods_Firestore_Example_iOS.framework */; };
 		DE03B2D41F2149D600A30B9C /* XCTest.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F5AF195388D20070C39A /* XCTest.framework */; };
@@ -217,6 +222,13 @@
 			remoteGlobalIDString = 6003F589195388D20070C39A;
 			remoteInfo = Firestore;
 		};
+		6EDD3AD320BF247500C33877 /* PBXContainerItemProxy */ = {
+			isa = PBXContainerItemProxy;
+			containerPortal = 6003F582195388D10070C39A /* Project object */;
+			proxyType = 1;
+			remoteGlobalIDString = 6003F589195388D20070C39A;
+			remoteInfo = Firestore;
+		};
 		DE03B2961F2149D600A30B9C /* PBXContainerItemProxy */ = {
 			isa = PBXContainerItemProxy;
 			containerPortal = 6003F582195388D10070C39A /* Project object */;
@@ -253,7 +265,7 @@
 		1277F98C20D2DF0867496976 /* Pods-Firestore_IntegrationTests_iOS.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Firestore_IntegrationTests_iOS.debug.xcconfig"; path = "Pods/Target Support Files/Pods-Firestore_IntegrationTests_iOS/Pods-Firestore_IntegrationTests_iOS.debug.xcconfig"; sourceTree = "<group>"; };
 		12F4357299652983A615F886 /* LICENSE */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text; name = LICENSE; path = ../LICENSE; sourceTree = "<group>"; };
 		132E36BB104830BD806351AC /* FSTLevelDBTransactionTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = FSTLevelDBTransactionTests.mm; sourceTree = "<group>"; };
-		2A0CF41BA5AED6049B0BEB2C /* type_traits_apple_test.mm */ = {isa = PBXFileReference; includeInIndex = 1; path = type_traits_apple_test.mm; sourceTree = "<group>"; };
+		2A0CF41BA5AED6049B0BEB2C /* type_traits_apple_test.mm */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.cpp.objcpp; path = type_traits_apple_test.mm; sourceTree = "<group>"; };
 		2B50B3A0DF77100EEE887891 /* Pods_Firestore_Tests_iOS.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods_Firestore_Tests_iOS.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		379B34A1536045869826D82A /* Pods_Firestore_Example_iOS_SwiftBuildTest.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods_Firestore_Example_iOS_SwiftBuildTest.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		3B843E4A1F3930A400548890 /* remote_store_spec_test.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = remote_store_spec_test.json; sourceTree = "<group>"; };
@@ -396,13 +408,18 @@
 		6003F5B9195388D20070C39A /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = en; path = en.lproj/InfoPlist.strings; sourceTree = "<group>"; };
 		6161B5012047140400A99DBB /* FIRFirestoreSourceTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = FIRFirestoreSourceTests.mm; sourceTree = "<group>"; };
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+		6EDD3B5B20BF247500C33877 /* Firestore_FuzzTests_iOS.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = Firestore_FuzzTests_iOS.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
+		6EDD3B5C20BF247500C33877 /* Firestore_FuzzTests_iOS-Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Firestore_FuzzTests_iOS-Info.plist"; sourceTree = "<group>"; };
+		6EDD3B5E20BF24D000C33877 /* FSTFuzzTestsPrincipal.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = FSTFuzzTestsPrincipal.mm; sourceTree = "<group>"; };
 		71719F9E1E33DC2100824A3D /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		7346E61C20325C6900FD6CEF /* FSTDispatchQueueTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = FSTDispatchQueueTests.mm; sourceTree = "<group>"; };
 		73866A9F2082B069009BB4FF /* FIRArrayTransformTests.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = FIRArrayTransformTests.mm; sourceTree = "<group>"; };
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+		84434E57CA72951015FC71BC /* Pods-Firestore_FuzzTests_iOS.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Firestore_FuzzTests_iOS.debug.xcconfig"; path = "Pods/Target Support Files/Pods-Firestore_FuzzTests_iOS/Pods-Firestore_FuzzTests_iOS.debug.xcconfig"; sourceTree = "<group>"; };
 		873B8AEA1B1F5CCA007FD442 /* Main.storyboard */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = file.storyboard; name = Main.storyboard; path = Base.lproj/Main.storyboard; sourceTree = "<group>"; };
 		8E002F4AD5D9B6197C940847 /* Firestore.podspec */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text; name = Firestore.podspec; path = ../Firestore.podspec; sourceTree = "<group>"; };
-		9CFD366B783AE27B9E79EE7A /* string_format_apple_test.mm */ = {isa = PBXFileReference; includeInIndex = 1; path = string_format_apple_test.mm; sourceTree = "<group>"; };
+		97C492D2524E92927C11F425 /* Pods-Firestore_FuzzTests_iOS.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Firestore_FuzzTests_iOS.release.xcconfig"; path = "Pods/Target Support Files/Pods-Firestore_FuzzTests_iOS/Pods-Firestore_FuzzTests_iOS.release.xcconfig"; sourceTree = "<group>"; };
+		9CFD366B783AE27B9E79EE7A /* string_format_apple_test.mm */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.cpp.objcpp; path = string_format_apple_test.mm; sourceTree = "<group>"; };
 		AB356EF6200EA5EB0089B766 /* field_value_test.cc */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = field_value_test.cc; sourceTree = "<group>"; };
 		AB380CF82019382300D97691 /* target_id_generator_test.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = target_id_generator_test.cc; sourceTree = "<group>"; };
 		AB380CFC201A2EE200D97691 /* string_util_test.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = string_util_test.cc; sourceTree = "<group>"; };
@@ -435,6 +452,7 @@
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 		B6FB4689208F9B9100554BA2 /* executor_libdispatch_test.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = executor_libdispatch_test.mm; sourceTree = "<group>"; };
 		B6FB468A208F9B9100554BA2 /* executor_test.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = executor_test.h; sourceTree = "<group>"; };
+		B79CA87A1A01FC5329031C9B /* Pods_Firestore_FuzzTests_iOS.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods_Firestore_FuzzTests_iOS.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		BB92EB03E3F92485023F64ED /* Pods_Firestore_Example_iOS_Firestore_SwiftTests_iOS.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods_Firestore_Example_iOS_Firestore_SwiftTests_iOS.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		D3CC3DC5338DCAF43A211155 /* README.md */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = net.daringfireball.markdown; name = README.md; path = ../README.md; sourceTree = "<group>"; };
 		DE03B2E91F2149D600A30B9C /* Firestore_IntegrationTests_iOS.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = Firestore_IntegrationTests_iOS.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -489,6 +507,17 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		6EDD3B4520BF247500C33877 /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				6EDD3B4620BF247500C33877 /* Foundation.framework in Frameworks */,
+				C482E724F4B10968417C3F78 /* Pods_Firestore_FuzzTests_iOS.framework in Frameworks */,
+				6EDD3B4820BF247500C33877 /* UIKit.framework in Frameworks */,
+				6EDD3B4920BF247500C33877 /* XCTest.framework in Frameworks */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		DE03B2D31F2149D600A30B9C /* Frameworks */ = {
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
@@ -630,6 +659,7 @@
 		6003F581195388D10070C39A = {
 			isa = PBXGroup;
 			children = (
+				6EDD3B5D20BF24A700C33877 /* FuzzTests */,
 				543B4F0520A91E4B001F506D /* App */,
 				60FF7A9C1954A5C5007DD14C /* Podspec Metadata */,
 				6003F5B5195388D20070C39A /* Tests */,
@@ -646,6 +676,7 @@
 			isa = PBXGroup;
 			children = (
 				6003F58A195388D20070C39A /* Firestore_Example_iOS.app */,
+				6EDD3B5B20BF247500C33877 /* Firestore_FuzzTests_iOS.xctest */,
 				DE03B2E91F2149D600A30B9C /* Firestore_IntegrationTests_iOS.xctest */,
 				54C9EDF12040E16300A969CD /* Firestore_SwiftTests_iOS.xctest */,
 				6003F5AE195388D20070C39A /* Firestore_Tests_iOS.xctest */,
@@ -662,6 +693,7 @@
 				5918805E993304321A05E82B /* Pods_Firestore_Example_iOS.framework */,
 				BB92EB03E3F92485023F64ED /* Pods_Firestore_Example_iOS_Firestore_SwiftTests_iOS.framework */,
 				379B34A1536045869826D82A /* Pods_Firestore_Example_iOS_SwiftBuildTest.framework */,
+				B79CA87A1A01FC5329031C9B /* Pods_Firestore_FuzzTests_iOS.framework */,
 				ECEBABC7E7B693BE808A1052 /* Pods_Firestore_IntegrationTests_iOS.framework */,
 				2B50B3A0DF77100EEE887891 /* Pods_Firestore_Tests_iOS.framework */,
 				6003F591195388D20070C39A /* UIKit.framework */,
@@ -731,6 +763,15 @@
 			name = "Podspec Metadata";
 			sourceTree = "<group>";
 		};
+		6EDD3B5D20BF24A700C33877 /* FuzzTests */ = {
+			isa = PBXGroup;
+			children = (
+				6EDD3B5E20BF24D000C33877 /* FSTFuzzTestsPrincipal.mm */,
+				6EDD3B5C20BF247500C33877 /* Firestore_FuzzTests_iOS-Info.plist */,
+			);
+			path = FuzzTests;
+			sourceTree = "<group>";
+		};
 		AAEA2A72CFD1FA5AD34462F7 /* Pods */ = {
 			isa = PBXGroup;
 			children = (
@@ -740,6 +781,8 @@
 				74ACEC3603BE58B57A7E8D4C /* Pods-Firestore_Example_iOS-SwiftBuildTest.release.xcconfig */,
 				3C81DE3772628FE297055662 /* Pods-Firestore_Example_iOS.debug.xcconfig */,
 				3F0992A4B83C60841C52E960 /* Pods-Firestore_Example_iOS.release.xcconfig */,
+				84434E57CA72951015FC71BC /* Pods-Firestore_FuzzTests_iOS.debug.xcconfig */,
+				97C492D2524E92927C11F425 /* Pods-Firestore_FuzzTests_iOS.release.xcconfig */,
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@@ -1045,6 +1088,26 @@
 			productReference = 6003F5AE195388D20070C39A /* Firestore_Tests_iOS.xctest */;
 			productType = "com.apple.product-type.bundle.unit-test";
 		};
+		6EDD3AD120BF247500C33877 /* Firestore_FuzzTests_iOS */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 6EDD3B5820BF247500C33877 /* Build configuration list for PBXNativeTarget "Firestore_FuzzTests_iOS" */;
+			buildPhases = (
+				6EDD3AD420BF247500C33877 /* [CP] Check Pods Manifest.lock */,
+				6EDD3AD520BF247500C33877 /* Sources */,
+				6EDD3B4520BF247500C33877 /* Frameworks */,
+				6EDD3B4A20BF247500C33877 /* Resources */,
+				6EDD3B5720BF247500C33877 /* [CP] Embed Pods Frameworks */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+				6EDD3AD220BF247500C33877 /* PBXTargetDependency */,
+			);
+			name = Firestore_FuzzTests_iOS;
+			productName = FirestoreTests;
+			productReference = 6EDD3B5B20BF247500C33877 /* Firestore_FuzzTests_iOS.xctest */;
+			productType = "com.apple.product-type.bundle.unit-test";
+		};
 		DE03B2941F2149D600A30B9C /* Firestore_IntegrationTests_iOS */ = {
 			isa = PBXNativeTarget;
 			buildConfigurationList = DE03B2E61F2149D600A30B9C /* Build configuration list for PBXNativeTarget "Firestore_IntegrationTests_iOS" */;
@@ -1104,6 +1167,9 @@
 						DevelopmentTeam = EQHXZ8M8AV;
 						TestTargetID = 6003F589195388D20070C39A;
 					};
+					6EDD3AD120BF247500C33877 = {
+						DevelopmentTeam = EQHXZ8M8AV;
+					};
 					DE03B2941F2149D600A30B9C = {
 						DevelopmentTeam = EQHXZ8M8AV;
 					};
@@ -1137,6 +1203,7 @@
 				DE03B2941F2149D600A30B9C /* Firestore_IntegrationTests_iOS */,
 				DE29E7F51F2174B000909613 /* AllTests_iOS */,
 				DE0761E31F2FE611003233AF /* SwiftBuildTest */,
+				6EDD3AD120BF247500C33877 /* Firestore_FuzzTests_iOS */,
 			);
 		};
 /* End PBXProject section */
@@ -1179,6 +1246,13 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		6EDD3B4A20BF247500C33877 /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		DE03B2D81F2149D600A30B9C /* Resources */ = {
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
@@ -1310,6 +1384,42 @@
 			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
 			showEnvVarsInLog = 0;
 		};
+		6EDD3AD420BF247500C33877 /* [CP] Check Pods Manifest.lock */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+				"${PODS_PODFILE_DIR_PATH}/Podfile.lock",
+				"${PODS_ROOT}/Manifest.lock",
+			);
+			name = "[CP] Check Pods Manifest.lock";
+			outputPaths = (
+				"$(DERIVED_FILE_DIR)/Pods-Firestore_FuzzTests_iOS-checkManifestLockResult.txt",
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
+			showEnvVarsInLog = 0;
+		};
+		6EDD3B5720BF247500C33877 /* [CP] Embed Pods Frameworks */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+				"${SRCROOT}/Pods/Target Support Files/Pods-Firestore_FuzzTests_iOS/Pods-Firestore_FuzzTests_iOS-frameworks.sh",
+				"${BUILT_PRODUCTS_DIR}/LibFuzzer/LibFuzzer.framework",
+			);
+			name = "[CP] Embed Pods Frameworks";
+			outputPaths = (
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/LibFuzzer.framework",
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-Firestore_FuzzTests_iOS/Pods-Firestore_FuzzTests_iOS-frameworks.sh\"\n";
+			showEnvVarsInLog = 0;
+		};
 		83F2AB95D08093BB076EE521 /* [CP] Check Pods Manifest.lock */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
@@ -1577,6 +1687,14 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		6EDD3AD520BF247500C33877 /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				6EDD3B6020BF25AE00C33877 /* FSTFuzzTestsPrincipal.mm in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		DE03B2981F2149D600A30B9C /* Sources */ = {
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
@@ -1629,6 +1747,11 @@
 			target = 6003F589195388D20070C39A /* Firestore_Example_iOS */;
 			targetProxy = 6003F5B3195388D20070C39A /* PBXContainerItemProxy */;
 		};
+		6EDD3AD220BF247500C33877 /* PBXTargetDependency */ = {
+			isa = PBXTargetDependency;
+			target = 6003F589195388D20070C39A /* Firestore_Example_iOS */;
+			targetProxy = 6EDD3AD320BF247500C33877 /* PBXContainerItemProxy */;
+		};
 		DE03B2951F2149D600A30B9C /* PBXTargetDependency */ = {
 			isa = PBXTargetDependency;
 			target = 6003F589195388D20070C39A /* Firestore_Example_iOS */;
@@ -1948,6 +2071,66 @@
 			};
 			name = Release;
 		};
+		6EDD3B5920BF247500C33877 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 84434E57CA72951015FC71BC /* Pods-Firestore_FuzzTests_iOS.debug.xcconfig */;
+			buildSettings = {
+				BUNDLE_LOADER = "$(TEST_HOST)";
+				DEVELOPMENT_TEAM = EQHXZ8M8AV;
+				FRAMEWORK_SEARCH_PATHS = (
+					"$(SDKROOT)/Developer/Library/Frameworks",
+					"$(inherited)",
+					"$(DEVELOPER_FRAMEWORKS_DIR)",
+				);
+				GCC_PRECOMPILE_PREFIX_HEADER = YES;
+				GCC_PREFIX_HEADER = "";
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"$(inherited)",
+					"COCOAPODS=1",
+					"GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1",
+				);
+				INFOPLIST_FILE = "FuzzTests/Firestore_FuzzTests_iOS-Info.plist";
+				OTHER_CFLAGS = (
+					"$(inherited)",
+					"-fsanitize-coverage=trace-pc-guard",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.demo.${PRODUCT_NAME:rfc1034identifier}";
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/Firestore_Example_iOS.app/Firestore_Example_iOS";
+				WRAPPER_EXTENSION = xctest;
+			};
+			name = Debug;
+		};
+		6EDD3B5A20BF247500C33877 /* Release */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 97C492D2524E92927C11F425 /* Pods-Firestore_FuzzTests_iOS.release.xcconfig */;
+			buildSettings = {
+				BUNDLE_LOADER = "$(TEST_HOST)";
+				DEVELOPMENT_TEAM = EQHXZ8M8AV;
+				FRAMEWORK_SEARCH_PATHS = (
+					"$(SDKROOT)/Developer/Library/Frameworks",
+					"$(inherited)",
+					"$(DEVELOPER_FRAMEWORKS_DIR)",
+				);
+				GCC_PRECOMPILE_PREFIX_HEADER = YES;
+				GCC_PREFIX_HEADER = "";
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"$(inherited)",
+					"COCOAPODS=1",
+					"GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1",
+				);
+				INFOPLIST_FILE = "FuzzTests/Firestore_FuzzTests_iOS-Info.plist";
+				OTHER_CFLAGS = (
+					"$(inherited)",
+					"-fsanitize-coverage=trace-pc-guard",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.demo.${PRODUCT_NAME:rfc1034identifier}";
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/Firestore_Example_iOS.app/Firestore_Example_iOS";
+				WRAPPER_EXTENSION = xctest;
+			};
+			name = Release;
+		};
 		DE03B2E71F2149D600A30B9C /* Debug */ = {
 			isa = XCBuildConfiguration;
 			baseConfigurationReference = 1277F98C20D2DF0867496976 /* Pods-Firestore_IntegrationTests_iOS.debug.xcconfig */;
@@ -2131,6 +2314,15 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
+		6EDD3B5820BF247500C33877 /* Build configuration list for PBXNativeTarget "Firestore_FuzzTests_iOS" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				6EDD3B5920BF247500C33877 /* Debug */,
+				6EDD3B5A20BF247500C33877 /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
 		DE03B2E61F2149D600A30B9C /* Build configuration list for PBXNativeTarget "Firestore_IntegrationTests_iOS" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
diff --git a/Firestore/Example/Firestore.xcodeproj/xcshareddata/xcschemes/Firestore_FuzzTests_iOS.xcscheme b/Firestore/Example/Firestore.xcodeproj/xcshareddata/xcschemes/Firestore_FuzzTests_iOS.xcscheme
new file mode 100644
index 0000000..039273b
--- /dev/null
+++ b/Firestore/Example/Firestore.xcodeproj/xcshareddata/xcschemes/Firestore_FuzzTests_iOS.xcscheme
@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0930"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      enableAddressSanitizer = "YES"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "6EDD3AD120BF247500C33877"
+               BuildableName = "Firestore_FuzzTests_iOS.xctest"
+               BlueprintName = "Firestore_FuzzTests_iOS"
+               ReferencedContainer = "container:Firestore.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/Firestore/Example/FuzzTests/FSTFuzzTestsPrincipal.mm b/Firestore/Example/FuzzTests/FSTFuzzTestsPrincipal.mm
new file mode 100644
index 0000000..63f6db0
--- /dev/null
+++ b/Firestore/Example/FuzzTests/FSTFuzzTestsPrincipal.mm
@@ -0,0 +1,64 @@
+/*
+ * 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.
+ */
+
+#import <Foundation/NSObject.h>
+
+#include "LibFuzzer/FuzzerDefs.h"
+
+namespace {
+
+// Contains the code to be fuzzed. Called by the fuzzing library with
+// different argument values for `data` and `size`.
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  // Code to be fuzz-tested here.
+  return 0;
+}
+
+// Simulates calling the main() function of libFuzzer (FuzzerMain.cpp).
+int RunFuzzTestingMain() {
+  // Arguments to libFuzzer main() function should be added to this array,
+  // e.g., dictionaries, corpus, number of runs, jobs, etc.
+  char *program_args[] = {
+      const_cast<char *>("RunFuzzTestingMain")  // First argument is program name.
+  };
+  char **argv = program_args;
+  int argc = sizeof(program_args) / sizeof(program_args[0]);
+
+  // Start fuzzing using libFuzzer's driver.
+  return fuzzer::FuzzerDriver(&argc, &argv, LLVMFuzzerTestOneInput);
+}
+
+}  // namespace
+
+/**
+ * This class is registered as the NSPrincipalClass in the
+ * Firestore_FuzzTests_iOS bundle's Info.plist. XCTest instantiates this class
+ * to perform one-time setup for the test bundle, as documented here:
+ *
+ *   https://developer.apple.com/documentation/xctest/xctestobservationcenter
+ */
+@interface FSTFuzzTestsPrincipal : NSObject
+@end
+
+@implementation FSTFuzzTestsPrincipal
+
+- (instancetype)init {
+  self = [super init];
+  RunFuzzTestingMain();
+  return self;
+}
+
+@end
diff --git a/Firestore/Example/FuzzTests/Firestore_FuzzTests_iOS-Info.plist b/Firestore/Example/FuzzTests/Firestore_FuzzTests_iOS-Info.plist
new file mode 100644
index 0000000..0d53e5f
--- /dev/null
+++ b/Firestore/Example/FuzzTests/Firestore_FuzzTests_iOS-Info.plist
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>${EXECUTABLE_NAME}</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundlePackageType</key>
+	<string>BNDL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>NSPrincipalClass</key>
+	<string>FSTFuzzTestsPrincipal</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+</dict>
+</plist>
diff --git a/Firestore/Example/Podfile b/Firestore/Example/Podfile
index 88cf93a..dc5af48 100644
--- a/Firestore/Example/Podfile
+++ b/Firestore/Example/Podfile
@@ -37,4 +37,10 @@ target 'Firestore_Example_iOS' do
   target 'SwiftBuildTest' do
     platform :ios, '8.0'
   end
+
+  target 'Firestore_FuzzTests_iOS' do
+    inherit! :search_paths
+
+    pod 'LibFuzzer', :podspec => 'LibFuzzer.podspec'
+  end
 end