diff --git a/Fingerprint.php b/Fingerprint.php
new file mode 100644
index 0000000..200ea5c
--- /dev/null
+++ b/Fingerprint.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace PHPMD;
+
+class Fingerprint
+{
+    const OVERRIDE_RULES = [
+      "CyclomaticComplexity",
+      "Design/LongClass",
+      "Design/LongMethod",
+    ];
+    private $name;
+    private $path;
+    private $rule;
+
+    public function __construct($path, $rule, $name)
+    {
+        $this->path = $path;
+        $this->rule = $rule;
+        $this->name = $name;
+    }
+
+    public function compute()
+    {
+        $fingerprint = null;
+
+        if (in_array($this->rule, self::OVERRIDE_RULES)) {
+            $fingerprint = md5($this->path . $this->rule . $this->name);
+        }
+
+        return $fingerprint;
+    }
+}
diff --git a/JSONRenderer.php b/JSONRenderer.php
index bb21e47..4f10757 100644
--- a/JSONRenderer.php
+++ b/JSONRenderer.php
@@ -5,6 +5,7 @@
 use PHPMD\AbstractRenderer;
 use PHPMD\Report;
 use PHPMD\Category\Category;
+use PHPMD\Fingerprint;
 
 class JSONRenderer extends AbstractRenderer
 {
@@ -44,6 +45,14 @@ public function renderReport(Report $report)
                 );
             }
 
+            $name = $violation->getMethodName() ?: $violation->getFunctionName() ?: $violation->getClassName();
+            $fingerprintObject = new Fingerprint($path, $checkName, $name);
+            $fingerprint = $fingerprintObject->compute();
+
+            if ($fingerprint) {
+                $issue["fingerprint"] = $fingerprint;
+            }
+
             $json = json_encode($issue, JSON_UNESCAPED_SLASHES, JSON_UNESCAPED_UNICODE);
             $writer->write($json);
             $writer->write(chr(0));
diff --git a/Makefile b/Makefile
index dc9047c..ea3e204 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: image composer-update
+.PHONY: image composer-update citest test
 
 IMAGE_NAME ?= codeclimate/codeclimate-phpmd
 
@@ -11,3 +11,9 @@ composer-update:
 	  --volume $(PWD)/composer.json:/usr/src/app/composer.json:ro \
 	  $(IMAGE_NAME) \
 	  sh -c 'php composer.phar update && cat composer.lock' > composer.lock
+
+citest:
+	docker run --rm $(IMAGE_NAME) vendor/bin/phpunit --bootstrap engine.php ./tests
+
+test: image
+	docker run -it --rm $(IMAGE_NAME) vendor/bin/phpunit --bootstrap engine.php ./tests
diff --git a/circle.yml b/circle.yml
index 480c1f8..68a8bb9 100644
--- a/circle.yml
+++ b/circle.yml
@@ -4,10 +4,14 @@ machine:
   environment:
     CLOUDSDK_CORE_DISABLE_PROMPTS: 1
     PRIVATE_REGISTRY: us.gcr.io/code_climate
+    IMAGE_NAME: $PRIVATE_REGISTRY/$CIRCLE_PROJECT_REPONAME:b$CIRCLE_BUILD_NUM
+dependencies:
+  override:
+    - make image
 
 test:
   override:
-    - docker build -t=$PRIVATE_REGISTRY/$CIRCLE_PROJECT_REPONAME:b$CIRCLE_BUILD_NUM .
+    - make citest
 
 deployment:
   registry:
diff --git a/composer.json b/composer.json
index 96f487e..758303f 100644
--- a/composer.json
+++ b/composer.json
@@ -2,5 +2,8 @@
     "require": {
         "phpmd/phpmd": "2.3.2",
         "barracudanetworks/forkdaemon-php": "1.0.*"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "5.3.*"
     }
 }
diff --git a/composer.lock b/composer.lock
index b7dce60..28330a5 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,8 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "hash": "9a209cc69d52ac030e11b8a2f1a32b6b",
-    "content-hash": "b10e93343b0c2899b3e44cba4f40d95a",
+    "hash": "f0c137ffd16746cbeabee997b32bfb1e",
+    "content-hash": "d8d4831b76188b3c7082e58ac873acb6",
     "packages": [
         {
             "name": "barracudanetworks/forkdaemon-php",
@@ -45,26 +45,26 @@
         },
         {
             "name": "pdepend/pdepend",
-            "version": "2.2.2",
+            "version": "2.2.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/pdepend/pdepend.git",
-                "reference": "d3ae0d084d526cdc6c3f1b858fb7148de77b41c5"
+                "reference": "b086687f3a01dc6bb92d633aef071d2c5dd0db06"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/pdepend/pdepend/zipball/d3ae0d084d526cdc6c3f1b858fb7148de77b41c5",
-                "reference": "d3ae0d084d526cdc6c3f1b858fb7148de77b41c5",
+                "url": "https://api.github.com/repos/pdepend/pdepend/zipball/b086687f3a01dc6bb92d633aef071d2c5dd0db06",
+                "reference": "b086687f3a01dc6bb92d633aef071d2c5dd0db06",
                 "shasum": ""
             },
             "require": {
                 "php": ">=5.3.7",
-                "symfony/config": "^2.3.0",
-                "symfony/dependency-injection": "^2.3.0",
-                "symfony/filesystem": "^2.3.0"
+                "symfony/config": "^2.3.0|^3",
+                "symfony/dependency-injection": "^2.3.0|^3",
+                "symfony/filesystem": "^2.3.0|^3"
             },
             "require-dev": {
-                "phpunit/phpunit": "^4.0.0,<4.8",
+                "phpunit/phpunit": "^4.4.0,<4.8",
                 "squizlabs/php_codesniffer": "^2.0.0"
             },
             "bin": [
@@ -72,8 +72,8 @@
             ],
             "type": "library",
             "autoload": {
-                "psr-0": {
-                    "PDepend\\": "src/main/php/"
+                "psr-4": {
+                    "PDepend\\": "src/main/php/PDepend"
                 }
             },
             "notification-url": "https://packagist.org/downloads/",
@@ -81,7 +81,7 @@
                 "BSD-3-Clause"
             ],
             "description": "Official version of pdepend to be handled with Composer",
-            "time": "2015-10-16 08:49:58"
+            "time": "2016-03-10 15:15:04"
         },
         {
             "name": "phpmd/phpmd",
@@ -150,26 +150,29 @@
         },
         {
             "name": "symfony/config",
-            "version": "v2.8.2",
+            "version": "v3.0.5",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/config.git",
-                "reference": "41ee6c70758f40fa1dbf90d019ae0a66c4a09e74"
+                "reference": "24f155da1ff180df8e15e34a8f6e2f8a0eadefa8"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/config/zipball/41ee6c70758f40fa1dbf90d019ae0a66c4a09e74",
-                "reference": "41ee6c70758f40fa1dbf90d019ae0a66c4a09e74",
+                "url": "https://api.github.com/repos/symfony/config/zipball/24f155da1ff180df8e15e34a8f6e2f8a0eadefa8",
+                "reference": "24f155da1ff180df8e15e34a8f6e2f8a0eadefa8",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.9",
-                "symfony/filesystem": "~2.3|~3.0.0"
+                "php": ">=5.5.9",
+                "symfony/filesystem": "~2.8|~3.0"
+            },
+            "suggest": {
+                "symfony/yaml": "To use the yaml reference dumper"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.8-dev"
+                    "dev-master": "3.0-dev"
                 }
             },
             "autoload": {
@@ -196,32 +199,29 @@
             ],
             "description": "Symfony Config Component",
             "homepage": "https://symfony.com",
-            "time": "2016-01-03 15:33:41"
+            "time": "2016-04-20 18:53:54"
         },
         {
             "name": "symfony/dependency-injection",
-            "version": "v2.8.2",
+            "version": "v3.0.5",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/dependency-injection.git",
-                "reference": "ba94a914e244e0d05f0aaef460d5558d5541d2b1"
+                "reference": "4973244b171257b987332386405b0f393230de52"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/dependency-injection/zipball/ba94a914e244e0d05f0aaef460d5558d5541d2b1",
-                "reference": "ba94a914e244e0d05f0aaef460d5558d5541d2b1",
+                "url": "https://api.github.com/repos/symfony/dependency-injection/zipball/4973244b171257b987332386405b0f393230de52",
+                "reference": "4973244b171257b987332386405b0f393230de52",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.9"
-            },
-            "conflict": {
-                "symfony/expression-language": "<2.6"
+                "php": ">=5.5.9"
             },
             "require-dev": {
-                "symfony/config": "~2.2|~3.0.0",
-                "symfony/expression-language": "~2.6|~3.0.0",
-                "symfony/yaml": "~2.1|~3.0.0"
+                "symfony/config": "~2.8|~3.0",
+                "symfony/expression-language": "~2.8|~3.0",
+                "symfony/yaml": "~2.8|~3.0"
             },
             "suggest": {
                 "symfony/config": "",
@@ -231,7 +231,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.8-dev"
+                    "dev-master": "3.0-dev"
                 }
             },
             "autoload": {
@@ -258,29 +258,29 @@
             ],
             "description": "Symfony DependencyInjection Component",
             "homepage": "https://symfony.com",
-            "time": "2016-01-12 17:46:01"
+            "time": "2016-04-25 11:17:47"
         },
         {
             "name": "symfony/filesystem",
-            "version": "v2.8.2",
+            "version": "v3.0.5",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/filesystem.git",
-                "reference": "637b64d0ee10f44ae98dbad651b1ecdf35a11e8c"
+                "reference": "74fec3511b62cb934b64bce1d96f06fffa4beafd"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/filesystem/zipball/637b64d0ee10f44ae98dbad651b1ecdf35a11e8c",
-                "reference": "637b64d0ee10f44ae98dbad651b1ecdf35a11e8c",
+                "url": "https://api.github.com/repos/symfony/filesystem/zipball/74fec3511b62cb934b64bce1d96f06fffa4beafd",
+                "reference": "74fec3511b62cb934b64bce1d96f06fffa4beafd",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.9"
+                "php": ">=5.5.9"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.8-dev"
+                    "dev-master": "3.0-dev"
                 }
             },
             "autoload": {
@@ -307,10 +307,1151 @@
             ],
             "description": "Symfony Filesystem Component",
             "homepage": "https://symfony.com",
-            "time": "2016-01-13 10:28:07"
+            "time": "2016-04-12 18:09:53"
+        }
+    ],
+    "packages-dev": [
+        {
+            "name": "doctrine/instantiator",
+            "version": "1.0.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/doctrine/instantiator.git",
+                "reference": "8e884e78f9f0eb1329e445619e04456e64d8051d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/doctrine/instantiator/zipball/8e884e78f9f0eb1329e445619e04456e64d8051d",
+                "reference": "8e884e78f9f0eb1329e445619e04456e64d8051d",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3,<8.0-DEV"
+            },
+            "require-dev": {
+                "athletic/athletic": "~0.1.8",
+                "ext-pdo": "*",
+                "ext-phar": "*",
+                "phpunit/phpunit": "~4.0",
+                "squizlabs/php_codesniffer": "~2.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Doctrine\\Instantiator\\": "src/Doctrine/Instantiator/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Marco Pivetta",
+                    "email": "ocramius@gmail.com",
+                    "homepage": "http://ocramius.github.com/"
+                }
+            ],
+            "description": "A small, lightweight utility to instantiate objects in PHP without invoking their constructors",
+            "homepage": "https://github.com/doctrine/instantiator",
+            "keywords": [
+                "constructor",
+                "instantiate"
+            ],
+            "time": "2015-06-14 21:17:01"
+        },
+        {
+            "name": "myclabs/deep-copy",
+            "version": "1.5.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/myclabs/DeepCopy.git",
+                "reference": "a8773992b362b58498eed24bf85005f363c34771"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/myclabs/DeepCopy/zipball/a8773992b362b58498eed24bf85005f363c34771",
+                "reference": "a8773992b362b58498eed24bf85005f363c34771",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0"
+            },
+            "require-dev": {
+                "doctrine/collections": "1.*",
+                "phpunit/phpunit": "~4.1"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "DeepCopy\\": "src/DeepCopy/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "Create deep copies (clones) of your objects",
+            "homepage": "https://github.com/myclabs/DeepCopy",
+            "keywords": [
+                "clone",
+                "copy",
+                "duplicate",
+                "object",
+                "object graph"
+            ],
+            "time": "2015-11-20 12:04:31"
+        },
+        {
+            "name": "phpdocumentor/reflection-docblock",
+            "version": "2.0.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpDocumentor/ReflectionDocBlock.git",
+                "reference": "d68dbdc53dc358a816f00b300704702b2eaff7b8"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpDocumentor/ReflectionDocBlock/zipball/d68dbdc53dc358a816f00b300704702b2eaff7b8",
+                "reference": "d68dbdc53dc358a816f00b300704702b2eaff7b8",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~4.0"
+            },
+            "suggest": {
+                "dflydev/markdown": "~1.0",
+                "erusev/parsedown": "~1.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-0": {
+                    "phpDocumentor": [
+                        "src/"
+                    ]
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Mike van Riel",
+                    "email": "mike.vanriel@naenius.com"
+                }
+            ],
+            "time": "2015-02-03 12:10:50"
+        },
+        {
+            "name": "phpspec/prophecy",
+            "version": "v1.6.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpspec/prophecy.git",
+                "reference": "3c91bdf81797d725b14cb62906f9a4ce44235972"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpspec/prophecy/zipball/3c91bdf81797d725b14cb62906f9a4ce44235972",
+                "reference": "3c91bdf81797d725b14cb62906f9a4ce44235972",
+                "shasum": ""
+            },
+            "require": {
+                "doctrine/instantiator": "^1.0.2",
+                "php": "^5.3|^7.0",
+                "phpdocumentor/reflection-docblock": "~2.0",
+                "sebastian/comparator": "~1.1",
+                "sebastian/recursion-context": "~1.0"
+            },
+            "require-dev": {
+                "phpspec/phpspec": "~2.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.5.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-0": {
+                    "Prophecy\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Konstantin Kudryashov",
+                    "email": "ever.zet@gmail.com",
+                    "homepage": "http://everzet.com"
+                },
+                {
+                    "name": "Marcello Duarte",
+                    "email": "marcello.duarte@gmail.com"
+                }
+            ],
+            "description": "Highly opinionated mocking framework for PHP 5.3+",
+            "homepage": "https://github.com/phpspec/prophecy",
+            "keywords": [
+                "Double",
+                "Dummy",
+                "fake",
+                "mock",
+                "spy",
+                "stub"
+            ],
+            "time": "2016-02-15 07:46:21"
+        },
+        {
+            "name": "phpunit/php-code-coverage",
+            "version": "3.3.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/php-code-coverage.git",
+                "reference": "2431befdd451fac43fbcde94d1a92fb3b8b68f86"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/php-code-coverage/zipball/2431befdd451fac43fbcde94d1a92fb3b8b68f86",
+                "reference": "2431befdd451fac43fbcde94d1a92fb3b8b68f86",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.6 || ^7.0",
+                "phpunit/php-file-iterator": "~1.3",
+                "phpunit/php-text-template": "~1.2",
+                "phpunit/php-token-stream": "^1.4.2",
+                "sebastian/code-unit-reverse-lookup": "~1.0",
+                "sebastian/environment": "^1.3.2",
+                "sebastian/version": "~1.0|~2.0"
+            },
+            "require-dev": {
+                "ext-xdebug": ">=2.1.4",
+                "phpunit/phpunit": "~5"
+            },
+            "suggest": {
+                "ext-dom": "*",
+                "ext-xdebug": ">=2.4.0",
+                "ext-xmlwriter": "*"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.3.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sb@sebastian-bergmann.de",
+                    "role": "lead"
+                }
+            ],
+            "description": "Library that provides collection, processing, and rendering functionality for PHP code coverage information.",
+            "homepage": "https://github.com/sebastianbergmann/php-code-coverage",
+            "keywords": [
+                "coverage",
+                "testing",
+                "xunit"
+            ],
+            "time": "2016-04-08 08:14:53"
+        },
+        {
+            "name": "phpunit/php-file-iterator",
+            "version": "1.4.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/php-file-iterator.git",
+                "reference": "6150bf2c35d3fc379e50c7602b75caceaa39dbf0"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/php-file-iterator/zipball/6150bf2c35d3fc379e50c7602b75caceaa39dbf0",
+                "reference": "6150bf2c35d3fc379e50c7602b75caceaa39dbf0",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.4.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sb@sebastian-bergmann.de",
+                    "role": "lead"
+                }
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+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Jeff Welch",
+                    "email": "whatthejeff@gmail.com"
+                },
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                },
+                {
+                    "name": "Adam Harvey",
+                    "email": "aharvey@php.net"
+                }
+            ],
+            "description": "Provides functionality to recursively process PHP variables",
+            "homepage": "http://www.github.com/sebastianbergmann/recursion-context",
+            "time": "2015-11-11 19:50:13"
+        },
+        {
+            "name": "sebastian/resource-operations",
+            "version": "1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/resource-operations.git",
+                "reference": "ce990bb21759f94aeafd30209e8cfcdfa8bc3f52"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/resource-operations/zipball/ce990bb21759f94aeafd30209e8cfcdfa8bc3f52",
+                "reference": "ce990bb21759f94aeafd30209e8cfcdfa8bc3f52",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Provides a list of PHP built-in functions that operate on resources",
+            "homepage": "https://www.github.com/sebastianbergmann/resource-operations",
+            "time": "2015-07-28 20:34:47"
+        },
+        {
+            "name": "sebastian/version",
+            "version": "2.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/version.git",
+                "reference": "c829badbd8fdf16a0bad8aa7fa7971c029f1b9c5"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/version/zipball/c829badbd8fdf16a0bad8aa7fa7971c029f1b9c5",
+                "reference": "c829badbd8fdf16a0bad8aa7fa7971c029f1b9c5",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.6"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de",
+                    "role": "lead"
+                }
+            ],
+            "description": "Library that helps with managing the version number of Git-hosted PHP projects",
+            "homepage": "https://github.com/sebastianbergmann/version",
+            "time": "2016-02-04 12:56:52"
+        },
+        {
+            "name": "symfony/yaml",
+            "version": "v3.0.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/yaml.git",
+                "reference": "0047c8366744a16de7516622c5b7355336afae96"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/yaml/zipball/0047c8366744a16de7516622c5b7355336afae96",
+                "reference": "0047c8366744a16de7516622c5b7355336afae96",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.5.9"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.0-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Component\\Yaml\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony Yaml Component",
+            "homepage": "https://symfony.com",
+            "time": "2016-03-04 07:55:57"
         }
     ],
-    "packages-dev": [],
     "aliases": [],
     "minimum-stability": "stable",
     "stability-flags": [],
diff --git a/engine.php b/engine.php
index c92385a..3b77585 100644
--- a/engine.php
+++ b/engine.php
@@ -11,6 +11,7 @@
 ini_set('memory_limit', -1);
 
 require_once __DIR__.'/vendor/autoload.php';
+require_once "Fingerprint.php";
 require_once "JSONRenderer.php";
 require_once "Runner.php";
 require_once "Category.php";
diff --git a/tests/FingerprintTest.php b/tests/FingerprintTest.php
new file mode 100644
index 0000000..078a3f7
--- /dev/null
+++ b/tests/FingerprintTest.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace PHPMD\Tests;
+
+use PHPMD\Fingerprint;
+
+class FingerprintTest extends \PHPUnit_Framework_TestCase
+{
+    public function testComputesFingerprintForMatchingRules()
+    {
+        $path = "some/path.php";
+        $rule = "CyclomaticComplexity";
+        $name = "foo";
+
+        $fingerprintObject = new Fingerprint($path, $rule, $name);
+        $fingerprint = $fingerprintObject->compute();
+
+        $this->assertEquals("2d8de996e0cf4d8b62b4b5fd6262c72d", $fingerprint);
+    }
+
+    public function testDoesNotComputeFingerprintForNonMatchingRules()
+    {
+        $path = "some/path.php";
+        $rule = "nomatch";
+        $name = "foo";
+
+        $fingerprintObject = new Fingerprint($path, $rule, $name);
+        $fingerprint = $fingerprintObject->compute();
+
+        $this->assertEquals(null, $fingerprint);
+    }
+}