diff --git a/Demo/librato-iOS Demo.xcodeproj/project.pbxproj b/Demo/librato-iOS Demo.xcodeproj/project.pbxproj
index 47a8310..5e85e56 100644
--- a/Demo/librato-iOS Demo.xcodeproj/project.pbxproj	
+++ b/Demo/librato-iOS Demo.xcodeproj/project.pbxproj	
@@ -57,6 +57,7 @@
 		71FE433FB985CA1AB0DF6BDA /* Pods-librato-iOS Demo.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-librato-iOS Demo.debug.xcconfig"; path = "Pods/Target Support Files/Pods-librato-iOS Demo/Pods-librato-iOS Demo.debug.xcconfig"; sourceTree = "<group>"; };
 		B3CFB32942D9D0C3245EEB4E /* Pods-librato-iOS Demo.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-librato-iOS Demo.release.xcconfig"; path = "Pods/Target Support Files/Pods-librato-iOS Demo/Pods-librato-iOS Demo.release.xcconfig"; sourceTree = "<group>"; };
 		C5A2D3C7197B48C6A9ACC07D /* libPods.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = libPods.a; sourceTree = BUILT_PRODUCTS_DIR; };
+		D9263DD61DB946660035CC6E /* NSString+SanitizedForMetricTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSString+SanitizedForMetricTests.m"; sourceTree = "<group>"; };
 		F8E7DC6EE1A84E81B6B7B7A2 /* libPods-librato-iOS Demo.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = "libPods-librato-iOS Demo.a"; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
 
@@ -147,6 +148,7 @@
 			isa = PBXGroup;
 			children = (
 				66922642180358B000237E77 /* librato_iOS_DemoTests.m */,
+				D9263DD61DB946660035CC6E /* NSString+SanitizedForMetricTests.m */,
 				6692263D180358B000237E77 /* Supporting Files */,
 			);
 			path = "librato-iOS DemoTests";
@@ -293,7 +295,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "diff \"${PODS_ROOT}/../Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [[ $? != 0 ]] ; then\n    cat << EOM\nerror: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\nEOM\n    exit 1\nfi\n";
+			shellScript = "diff \"${PODS_ROOT}/../Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n";
 			showEnvVarsInLog = 0;
 		};
 		CF311E2286F14B79A814F7BE /* [CP] Copy Pods Resources */ = {
@@ -329,6 +331,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				66922643180358B000237E77 /* librato_iOS_DemoTests.m in Sources */,
+				D9263DD71DB946660035CC6E /* NSString+SanitizedForMetricTests.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/Demo/librato-iOS DemoTests/NSString+SanitizedForMetricTests.m b/Demo/librato-iOS DemoTests/NSString+SanitizedForMetricTests.m
new file mode 100644
index 0000000..f7323cd
--- /dev/null
+++ b/Demo/librato-iOS DemoTests/NSString+SanitizedForMetricTests.m	
@@ -0,0 +1,36 @@
+//
+//  NSString+SanitizedForMetricTests.m
+//  librato-iOS
+//
+//  Created by Sergey Kuryanov on 20.10.16.
+//  Copyright © 2016 Amco International Education Services, LLC. All rights reserved.
+//
+
+#import <XCTest/XCTest.h>
+#import "NSString+SanitizedForMetric.h"
+
+@interface NSString_SanitizedForMetricTests : XCTestCase
+@property (nonatomic, strong) NSString *testString;
+@end
+
+@implementation NSString_SanitizedForMetricTests
+
+- (void)setUp {
+    [super setUp];
+    
+    self.testString = @"A-Za-z0-9.:-_<>{}[];\'\"!@#$%^&*()_+=œ∑´®†¥¨ˆøπ“‘«åß∂ƒ©˙∆˚¬…æΩ≈ç√∫˜µ≤≥÷";
+}
+
+- (void)tearDown {
+    self.testString = nil;
+    
+    [super tearDown];
+}
+
+- (void)testThatOnlyAllowedCharactersPresent {
+    NSString *expectedString = @"A-Za-z0-9.:-_-------------------_------------------------------------";
+    
+    XCTAssertEqualObjects(self.testString.sanitizedForMetric, expectedString);
+}
+
+@end
diff --git a/Demo/librato-iOS DemoTests/librato_iOS_DemoTests.m b/Demo/librato-iOS DemoTests/librato_iOS_DemoTests.m
index 780d094..7821fcc 100644
--- a/Demo/librato-iOS DemoTests/librato_iOS_DemoTests.m	
+++ b/Demo/librato-iOS DemoTests/librato_iOS_DemoTests.m	
@@ -26,9 +26,5 @@ - (void)tearDown
     [super tearDown];
 }
 
-- (void)testExample
-{
-    XCTFail(@"No implementation for \"%s\"", __PRETTY_FUNCTION__);
-}
 
 @end