diff --git a/Makefile b/Makefile
index a9c66e39..e065c876 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@ help:
 ## Build
 ##---------------------------------------------------------------------------
 
-build:            ## Build the PHAR
+build:		## Build the PHAR
 build: vendor
 	# Cleanup existing artefacts
 	rm -f bin/php-scoper.phar
@@ -42,18 +42,18 @@ build: vendor
 ## Tests
 ##---------------------------------------------------------------------------
 
-test:             ## Run all the tests
+test:		## Run all the tests
 test: tu e2e
 
-tu:               ## Run PHPUnit tests
+tu:		## Run PHPUnit tests
 tu: vendor
 	php -d zend.enable_gc=0 $(PHPUNIT)
 
-tc:               ## Run PHPUnit tests with test coverage
+tc:		## Run PHPUnit tests with test coverage
 tc: vendor
 	phpdbg -qrr -d zend.enable_gc=0 $(PHPUNIT) --coverage-html=dist/coverage --coverage-text
 
-e2e:			  ## Run end-to-end tests
+e2e:		## Run end-to-end tests
 e2e: scoper
 	php -d zend.enable_gc=0 $(PHPSCOPER) add-prefix fixtures/set004 -o build/set004 -f
 	composer -d=build/set004 dump-autoload
@@ -67,7 +67,7 @@ e2e: scoper
 	php build/set005/bin/greet.phar > build/output
 	diff fixtures/set005/expected-output build/output
 
-tb:				  ## Run Blackfire profiling
+tb:		## Run Blackfire profiling
 tb: vendor
 	rm -rf build
   	#
diff --git a/fixtures/set006/scoper.inc.php b/fixtures/set006/scoper.inc.php
new file mode 100644
index 00000000..1b654078
--- /dev/null
+++ b/fixtures/set006/scoper.inc.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+return [
+    function () {
+        return 'Hello world!';
+    }
+];
diff --git a/fixtures/set007/.gitkeep b/fixtures/set007/.gitkeep
new file mode 100644
index 00000000..e69de29b
diff --git a/fixtures/set008/scoper.inc.php b/fixtures/set008/scoper.inc.php
new file mode 100644
index 00000000..949602ac
--- /dev/null
+++ b/fixtures/set008/scoper.inc.php
@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=1);
+
+return 'string value';
\ No newline at end of file
diff --git a/fixtures/set009/scoper.inc.php b/fixtures/set009/scoper.inc.php
new file mode 100644
index 00000000..5ab22d14
--- /dev/null
+++ b/fixtures/set009/scoper.inc.php
@@ -0,0 +1,7 @@
+<?php
+
+declare(strict_types=1);
+
+return [
+    'string value'
+];
\ No newline at end of file
diff --git a/scoper.inc.php b/scoper.inc.php
new file mode 100644
index 00000000..b7b55131
--- /dev/null
+++ b/scoper.inc.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the humbug/php-scoper package.
+ *
+ * Copyright (c) 2017 Théo FIDRY <theo.fidry@gmail.com>,
+ *                    Pádraic Brady <padraic.brady@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+return [
+    function (string $filePath, string $prefix, string $content): string {
+        //
+        // PHP-Parser patch
+        //
+
+        if ($filePath === realpath(__DIR__.'vendor/nikic/php-parser/lib/PhpParser/Lexer.php')) {
+            return preg_replace(
+                '%if \(defined\(\$name \= \'PhpParser\\\\Parser\\\\Tokens\:\:\'%',
+                <<<'PHP'
+$ns = explode(\'\\\\\', __NAMESPACE__);
+if (defined($name = array_shift($ns) . '\\\\' . 'PhpParser\\\\Parser\\\\Tokens::'
+PHP
+                ,
+                $content
+            );
+        }
+
+        if ($filePath === realpath(__DIR__.'vendor/nikic/php-parser/lib/PhpParser/NodeAbstract.php')) {
+            return preg_replace(
+                '%rtrim\(get_class\(\$this\), \'\'_\'\'\), 15\)%',
+                'rtrim(get_class($this), \'_\'), 15+23)',
+                $content
+            );
+        }
+
+        return $content;
+    },
+];
diff --git a/src/Console/Command/AddPrefixCommand.php b/src/Console/Command/AddPrefixCommand.php
index 176785f3..70955904 100644
--- a/src/Console/Command/AddPrefixCommand.php
+++ b/src/Console/Command/AddPrefixCommand.php
@@ -37,6 +37,10 @@ final class AddPrefixCommand extends Command
     const OUTPUT_DIR_OPT = 'output-dir';
     /** @internal */
     const FORCE_OPT = 'force';
+    /** @internal */
+    const PATCH_FILE = 'patch-file';
+    /** @internal */
+    const PATCH_FILE_DEFAULT = 'scoper.inc.php';
 
     private $fileSystem;
     private $handle;
@@ -69,7 +73,7 @@ protected function configure()
                 self::PREFIX_OPT,
                 'p',
                 InputOption::VALUE_REQUIRED,
-                'The namespace prefix to add'
+                'The namespace prefix to add.'
             )
             ->addOption(
                 self::OUTPUT_DIR_OPT,
@@ -82,7 +86,17 @@ protected function configure()
                 self::FORCE_OPT,
                 'f',
                 InputOption::VALUE_NONE,
-                'Deletes any existing content in the output directory without any warning'
+                'Deletes any existing content in the output directory without any warning.'
+            )
+            ->addOption(
+                self::PATCH_FILE,
+                'c',
+                InputOption::VALUE_REQUIRED,
+                sprintf(
+                    'Configuration file for the patchers. Will use "%s" if found by default',
+                    self::PATCH_FILE_DEFAULT
+                ),
+                null
             )
         ;
     }
@@ -97,6 +111,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         $this->validatePrefix($input);
         $this->validatePaths($input);
         $this->validateOutputDir($input, $io);
+        $patchers = $this->validatePatchers($input, $io);
 
         $logger = new ConsoleLogger(
             $this->getApplication(),
@@ -113,6 +128,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
                 $input->getOption(self::PREFIX_OPT),
                 $input->getArgument(self::PATH_ARG),
                 $input->getOption(self::OUTPUT_DIR_OPT),
+                $patchers,
                 $logger
             );
         } catch (Throwable $throwable) {
@@ -234,4 +250,83 @@ private function validateOutputDir(InputInterface $input, OutputStyle $io)
             $this->fileSystem->remove($outputDir);
         }
     }
+
+    /**
+     * @param InputInterface $input
+     * @param OutputStyle    $io
+     *
+     * @return callable[]
+     */
+    private function validatePatchers(InputInterface $input, OutputStyle $io): array
+    {
+        $patchFile = $input->getOption(self::PATCH_FILE);
+
+        if (null === $patchFile) {
+            $patchFile = $this->makeAbsolutePath(self::PATCH_FILE_DEFAULT);
+
+            if (false === file_exists($patchFile)) {
+                $io->writeln(
+                    sprintf(
+                        'Patch file "%s" not found. Skipping.',
+                        $patchFile
+                    ),
+                    OutputStyle::VERBOSITY_DEBUG
+                );
+
+                return [];
+            }
+        } else {
+            $patchFile = $this->makeAbsolutePath($patchFile);
+        }
+
+        if (false === file_exists($patchFile)) {
+            throw new RuntimeException(
+                sprintf(
+                    'Could not find the file "%s".',
+                    $patchFile
+                )
+            );
+        }
+
+        $io->writeln(
+            sprintf(
+                'Using the configuration file "%s".',
+                $patchFile
+            ),
+            OutputStyle::VERBOSITY_DEBUG
+        );
+
+        $patchers = include $patchFile;
+
+        if (false === is_array($patchers)) {
+            throw new RuntimeException(
+                sprintf(
+                    'Expected patchers to be an array of callables, found "%s" instead.',
+                    gettype($patchers)
+                )
+            );
+        }
+
+        foreach ($patchers as $index => $patcher) {
+            if (false === is_callable($patcher)) {
+                throw new RuntimeException(
+                    sprintf(
+                        'Expected patchers to be an array of callables, the "%d" element is not.',
+                        $index
+                    )
+                );
+            }
+        }
+
+        return $patchers;
+    }
+
+    private function makeAbsolutePath(string $path): string
+    {
+        if (false === $this->fileSystem->isAbsolutePath($path)) {
+            $path = getcwd().DIRECTORY_SEPARATOR.$path;
+        }
+
+        return $path;
+    }
 }
diff --git a/src/Handler/HandleAddPrefix.php b/src/Handler/HandleAddPrefix.php
index 659c8773..8fac5cc3 100644
--- a/src/Handler/HandleAddPrefix.php
+++ b/src/Handler/HandleAddPrefix.php
@@ -42,19 +42,20 @@ public function __construct(Scoper $scoper)
     /**
      * Apply prefix to all the code found in the given paths, AKA scope all the files found.
      *
-     * @param string        $prefix e.g. 'Foo'
-     * @param string[]      $paths  List of files to scan (absolute paths)
-     * @param string        $output absolute path to the output directory
+     * @param string        $prefix   e.g. 'Foo'
+     * @param string[]      $paths    List of files to scan (absolute paths)
+     * @param string        $output   absolute path to the output directory
+     * @param callable[]    $patchers
      * @param ConsoleLogger $logger
      */
-    public function __invoke(string $prefix, array $paths, string $output, ConsoleLogger $logger)
+    public function __invoke(string $prefix, array $paths, string $output, array $patchers, ConsoleLogger $logger)
     {
         $this->fileSystem->mkdir($output);
 
         try {
             $files = $this->retrieveFiles($paths, $output);
 
-            $this->scopeFiles($files, $prefix, $logger);
+            $this->scopeFiles($files, $prefix, $patchers, $logger);
         } catch (Throwable $throwable) {
             $this->fileSystem->remove($output);
 
@@ -141,22 +142,35 @@ function (array $files, string $file) use ($output, $commonPath): array {
     /**
      * @param string[]      $files
      * @param string        $prefix
+     * @param callable[]    $patchers
      * @param ConsoleLogger $logger
      */
-    private function scopeFiles(array $files, string $prefix, ConsoleLogger $logger)
+    private function scopeFiles(array $files, string $prefix, array $patchers, ConsoleLogger $logger)
     {
         $count = count($files);
         $logger->outputFileCount($count);
 
         foreach ($files as $inputFilePath => $outputFilePath) {
-            $this->scopeFile($inputFilePath, $outputFilePath, $prefix, $logger);
+            $this->scopeFile($inputFilePath, $outputFilePath, $prefix, $patchers, $logger);
         }
     }
 
-    private function scopeFile(string $inputFilePath, string $outputFilePath, string $prefix, ConsoleLogger $logger)
-    {
+    /**
+     * @param string        $inputFilePath
+     * @param string        $outputFilePath
+     * @param string        $prefix
+     * @param callable[]    $patchers
+     * @param ConsoleLogger $logger
+     */
+    private function scopeFile(
+        string $inputFilePath,
+        string $outputFilePath,
+        string $prefix,
+        array $patchers,
+        ConsoleLogger $logger
+    ) {
         try {
-            $scoppedContent = $this->scoper->scope($inputFilePath, $prefix);
+            $scoppedContent = $this->scoper->scope($inputFilePath, $prefix, $patchers);
         } catch (PhpParserError $error) {
             throw new ParsingException(
                 sprintf(
diff --git a/src/Scoper.php b/src/Scoper.php
index 8c9b1381..e5e7b71c 100644
--- a/src/Scoper.php
+++ b/src/Scoper.php
@@ -21,12 +21,13 @@ interface Scoper
     /**
      * Scope AKA. apply the given prefix to the file in the appropriate way.
      *
-     * @param string $filePath File to scope
-     * @param string $prefix   Prefix to apply to the file
+     * @param string     $filePath File to scope
+     * @param string     $prefix   Prefix to apply to the file
+     * @param callable[] $patchers
      *
      * @throws ParsingException
      *
      * @return string Content of the file with the prefix applied
      */
-    public function scope(string $filePath, string $prefix): string;
+    public function scope(string $filePath, string $prefix, array $patchers): string;
 }
diff --git a/src/Scoper/Composer/InstalledPackagesScoper.php b/src/Scoper/Composer/InstalledPackagesScoper.php
index 796a19d5..e0b7eaa3 100644
--- a/src/Scoper/Composer/InstalledPackagesScoper.php
+++ b/src/Scoper/Composer/InstalledPackagesScoper.php
@@ -44,14 +44,14 @@ public function __construct(Scoper $decoratedScoper)
      *
      * {@inheritdoc}
      */
-    public function scope(string $filePath, string $prefix): string
+    public function scope(string $filePath, string $prefix, array $patchers): string
     {
         if (null === self::$filePattern) {
             throw new LogicException('Cannot be used without being initialised first.');
         }
 
         if (1 !== preg_match(self::$filePattern, $filePath)) {
-            return $this->decoratedScoper->scope($filePath, $prefix);
+            return $this->decoratedScoper->scope($filePath, $prefix, $patchers);
         }
 
         $decodedJson = json_decode(
diff --git a/src/Scoper/Composer/JsonFileScoper.php b/src/Scoper/Composer/JsonFileScoper.php
index c3ba438d..40652603 100644
--- a/src/Scoper/Composer/JsonFileScoper.php
+++ b/src/Scoper/Composer/JsonFileScoper.php
@@ -30,10 +30,10 @@ public function __construct(Scoper $decoratedScoper)
      *
      * {@inheritdoc}
      */
-    public function scope(string $filePath, string $prefix): string
+    public function scope(string $filePath, string $prefix, array $patchers): string
     {
         if (1 !== preg_match('/composer\.json$/', $filePath)) {
-            return $this->decoratedScoper->scope($filePath, $prefix);
+            return $this->decoratedScoper->scope($filePath, $prefix, $patchers);
         }
 
         $decodedJson = json_decode(
diff --git a/src/Scoper/NullScoper.php b/src/Scoper/NullScoper.php
index 6f8adf37..57efe186 100644
--- a/src/Scoper/NullScoper.php
+++ b/src/Scoper/NullScoper.php
@@ -21,7 +21,7 @@ final class NullScoper implements Scoper
     /**
      * @inheritdoc
      */
-    public function scope(string $filePath, string $prefix): string
+    public function scope(string $filePath, string $prefix, array $patchers): string
     {
         return file_get_contents($filePath);
     }
diff --git a/src/Scoper/PatchScoper.php b/src/Scoper/PatchScoper.php
new file mode 100644
index 00000000..3d020699
--- /dev/null
+++ b/src/Scoper/PatchScoper.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the humbug/php-scoper package.
+ *
+ * Copyright (c) 2017 Théo FIDRY <theo.fidry@gmail.com>,
+ *                    Pádraic Brady <padraic.brady@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Humbug\PhpScoper\Scoper;
+
+use Humbug\PhpScoper\Scoper;
+
+final class PatchScoper implements Scoper
+{
+    private $decoratedScoper;
+
+    public function __construct(Scoper $decoratedScoper)
+    {
+        $this->decoratedScoper = $decoratedScoper;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function scope(string $filePath, string $prefix, array $patchers): string
+    {
+        $content = $this->decoratedScoper->scope($filePath, $prefix, $patchers);
+
+        return array_reduce(
+            $patchers,
+            function (string $content, callable $patcher) use ($filePath, $prefix): string {
+                return $patcher($filePath, $prefix, $content);
+            },
+            $content
+        );
+    }
+}
diff --git a/src/Scoper/PhpScoper.php b/src/Scoper/PhpScoper.php
index 4614cd12..8e83e957 100644
--- a/src/Scoper/PhpScoper.php
+++ b/src/Scoper/PhpScoper.php
@@ -53,10 +53,10 @@ public function __construct(Parser $parser, Scoper $decoratedScoper)
      *
      * @throws PhpParserError
      */
-    public function scope(string $filePath, string $prefix): string
+    public function scope(string $filePath, string $prefix, array $patchers): string
     {
         if (false === $this->isPhpFile($filePath)) {
-            return $this->decoratedScoper->scope($filePath, $prefix);
+            return $this->decoratedScoper->scope($filePath, $prefix, $patchers);
         }
 
         $content = file_get_contents($filePath);
diff --git a/src/functions.php b/src/functions.php
index 4f9a087f..0d94e5a5 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -20,6 +20,7 @@
 use Humbug\PhpScoper\Scoper\Composer\InstalledPackagesScoper;
 use Humbug\PhpScoper\Scoper\Composer\JsonFileScoper;
 use Humbug\PhpScoper\Scoper\NullScoper;
+use Humbug\PhpScoper\Scoper\PatchScoper;
 use Humbug\PhpScoper\Scoper\PhpScoper;
 use PackageVersions\Versions;
 use PhpParser\Parser;
@@ -63,11 +64,13 @@ function get_version(): string
  */
 function create_scoper(): Scoper
 {
-    return new JsonFileScoper(
-        new InstalledPackagesScoper(
-            new PhpScoper(
-                create_parser(),
-                new NullScoper()
+    return new PatchScoper(
+        new JsonFileScoper(
+            new InstalledPackagesScoper(
+                new PhpScoper(
+                    create_parser(),
+                    new NullScoper()
+                )
             )
         )
     );
diff --git a/tests/Console/Command/AddPrefixCommandTest.php b/tests/Console/Command/AddPrefixCommandTest.php
index 7c96f986..6a8aed35 100644
--- a/tests/Console/Command/AddPrefixCommandTest.php
+++ b/tests/Console/Command/AddPrefixCommandTest.php
@@ -21,6 +21,7 @@
 use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
 use Prophecy\Prophecy\ObjectProphecy;
+use Symfony\Component\Console\Exception\RuntimeException;
 use Symfony\Component\Console\Exception\RuntimeException as SymfonyConsoleRuntimeException;
 use Symfony\Component\Console\Tester\ApplicationTester;
 use Symfony\Component\Filesystem\Filesystem;
@@ -32,6 +33,8 @@
  */
 class AddPrefixCommandTest extends TestCase
 {
+    const FIXTURE_PATH = __DIR__.'/../../../fixtures';
+
     /**
      * @var ApplicationTester
      */
@@ -164,6 +167,7 @@ public function test_scope_the_given_paths()
             '--no-interaction',
         ];
 
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
         $this->fileSystemProphecy->exists(Argument::cetera())->willReturn(false);
 
@@ -176,6 +180,7 @@ public function test_scope_the_given_paths()
                     escape_path('/path/to/file'),
                 ],
                 $this->tmp,
+                Argument::type('array'),
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -185,7 +190,8 @@ public function test_scope_the_given_paths()
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(4);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->shouldHaveBeenCalledTimes(1);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(5);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -203,6 +209,7 @@ public function test_applies_a_random_prefix_when_none_given()
             '--output-dir' => $this->tmp,
         ];
 
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
         $this->fileSystemProphecy->exists(Argument::cetera())->willReturn(false);
 
@@ -224,6 +231,7 @@ function (string $prefix): bool {
                     escape_path('/path/to/file'),
                 ],
                 $this->tmp,
+                Argument::type('array'),
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -233,7 +241,8 @@ function (string $prefix): bool {
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(4);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->shouldHaveBeenCalledTimes(1);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(5);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -248,6 +257,7 @@ public function test_scope_the_current_working_directory_if_no_path_given()
         ];
 
         $this->fileSystemProphecy->isAbsolutePath($this->tmp)->willReturn(true);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->exists($this->tmp)->willReturn(false);
 
         $this->handleProphecy
@@ -257,6 +267,7 @@ public function test_scope_the_current_working_directory_if_no_path_given()
                     $this->cwd,
                 ],
                 $this->tmp,
+                Argument::type('array'),
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -266,7 +277,8 @@ public function test_scope_the_current_working_directory_if_no_path_given()
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(1);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->shouldHaveBeenCalledTimes(1);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(2);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -289,6 +301,7 @@ public function test_relative_paths_are_relative_to_the_current_working_director
         $this->fileSystemProphecy->isAbsolutePath($path1)->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath($path2)->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath($this->tmp)->willReturn(true);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->exists($this->tmp)->willReturn(false);
 
         $this->handleProphecy
@@ -300,6 +313,7 @@ public function test_relative_paths_are_relative_to_the_current_working_director
                     escape_path($this->cwd.'/relative-path/to/file'),
                 ],
                 $this->tmp,
+                Argument::type('array'),
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -309,7 +323,7 @@ public function test_relative_paths_are_relative_to_the_current_working_director
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(4);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(5);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -328,6 +342,7 @@ public function test_prefix_can_end_by_a_backslash()
             '--output-dir' => $this->tmp,
         ];
 
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
         $this->fileSystemProphecy->exists($this->tmp)->willReturn(false);
 
@@ -340,6 +355,7 @@ public function test_prefix_can_end_by_a_backslash()
                     escape_path('/path/to/file'),
                 ],
                 $this->tmp,
+                Argument::type('array'),
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -349,7 +365,8 @@ public function test_prefix_can_end_by_a_backslash()
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(4);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->shouldHaveBeenCalledTimes(1);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(5);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -368,6 +385,7 @@ public function test_prefix_can_end_by_multiple_backslashes()
             '--output-dir' => $this->tmp,
         ];
 
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
         $this->fileSystemProphecy->exists($this->tmp)->willReturn(false);
 
@@ -380,6 +398,7 @@ public function test_prefix_can_end_by_multiple_backslashes()
                     escape_path('/path/to/file'),
                 ],
                 $this->tmp,
+                Argument::type('array'),
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -389,7 +408,8 @@ public function test_prefix_can_end_by_multiple_backslashes()
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(4);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->shouldHaveBeenCalledTimes(1);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(5);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -406,6 +426,7 @@ public function test_an_output_directory_can_be_given()
             '--output-dir' => $outDir = $this->tmp.DIRECTORY_SEPARATOR.'output-dir',
         ];
 
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
         $this->fileSystemProphecy->exists($outDir)->willReturn(false);
 
@@ -416,6 +437,7 @@ public function test_an_output_directory_can_be_given()
                     escape_path('/path/to/dir1'),
                 ],
                 $outDir,
+                Argument::type('array'),
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -425,7 +447,8 @@ public function test_an_output_directory_can_be_given()
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(2);
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->shouldHaveBeenCalledTimes(1);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(3);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -446,6 +469,7 @@ public function test_relative_output_directory_are_made_absolute()
 
         $expectedOutputDir = $this->tmp.DIRECTORY_SEPARATOR.'output-dir';
 
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath('output-dir')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
         $this->fileSystemProphecy->exists($expectedOutputDir)->willReturn(false);
@@ -457,6 +481,7 @@ public function test_relative_output_directory_are_made_absolute()
                     escape_path('/path/to/dir1'),
                 ],
                 $expectedOutputDir,
+                [],
                 Argument::type(ConsoleLogger::class)
             )
             ->shouldBeCalled()
@@ -466,7 +491,7 @@ public function test_relative_output_directory_are_made_absolute()
 
         $this->assertSame(0, $this->appTester->getStatusCode());
 
-        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(2);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->shouldHaveBeenCalledTimes(3);
         $this->fileSystemProphecy->exists(Argument::cetera())->shouldHaveBeenCalledTimes(1);
 
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
@@ -513,6 +538,7 @@ public function test_throws_an_error_when_scoping_fails()
             ],
         ];
 
+        $this->fileSystemProphecy->isAbsolutePath('scoper.inc.php')->willReturn(false);
         $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
         $this->fileSystemProphecy->exists('build')->willReturn(false);
 
@@ -534,6 +560,150 @@ public function test_throws_an_error_when_scoping_fails()
         $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
     }
 
+    public function test_throws_an_error_when_passing_a_non_existent_path_file()
+    {
+        $input = [
+            'add-prefix',
+            '--prefix' => 'MyPrefix',
+            '--patch-file' => 'unknown',
+            'paths' => [
+                escape_path('/path/to/dir1'),
+            ],
+        ];
+
+        $this->fileSystemProphecy->isAbsolutePath('unknown')->willReturn(false);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
+        $this->fileSystemProphecy->exists('build')->willReturn(false);
+
+        $this->handleProphecy->__invoke(Argument::cetera())->shouldNotBeCalled();
+
+        try {
+            $this->appTester->run($input);
+
+            $this->fail('Expected exception to be thrown.');
+        } catch (RuntimeException $exception) {
+            $patchFile = escape_path($this->cwd.'/unknown');
+
+            $this->assertSame(
+                "Could not find the file \"$patchFile\".",
+                $exception->getMessage()
+            );
+            $this->assertSame(0, $exception->getCode());
+            $this->assertNull($exception->getPrevious());
+        }
+    }
+
+    public function test_attemps_to_use_patch_file_in_current_directory()
+    {
+        chdir(escape_path(self::FIXTURE_PATH.'/set006'));
+
+        $input = [
+            'add-prefix',
+            '--prefix' => 'MyPrefix',
+            'paths' => [
+                escape_path('/path/to/dir1'),
+            ],
+        ];
+
+        $this->fileSystemProphecy->isAbsolutePath('unknown')->willReturn(false);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
+        $this->fileSystemProphecy->exists('build')->willReturn(false);
+
+        $patchersFound = [];
+        $this->handleProphecy
+            ->__invoke(
+                Argument::any(),
+                Argument::any(),
+                Argument::any(),
+                Argument::that(function ($arg) use (&$patchersFound) {
+                    $patchersFound = $arg;
+
+                    return true;
+                }),
+                Argument::any()
+            )
+            ->shouldBeCalled();
+
+        $this->appTester->run($input);
+
+        $this->assertCount(1, $patchersFound);
+        $this->assertEquals('Hello world!', $patchersFound[0]());
+
+        $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
+    }
+
+    public function test_do_no_apply_any_patcher_if_default_patcher_file_not_found()
+    {
+        chdir(escape_path(self::FIXTURE_PATH.'/set007'));
+
+        $input = [
+            'add-prefix',
+            '--prefix' => 'MyPrefix',
+            'paths' => [
+                escape_path('/path/to/dir1'),
+            ],
+        ];
+
+        $this->fileSystemProphecy->isAbsolutePath('unknown')->willReturn(false);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
+        $this->fileSystemProphecy->exists('build')->willReturn(false);
+
+        $patchersFound = [];
+        $this->handleProphecy
+            ->__invoke(
+                Argument::any(),
+                Argument::any(),
+                Argument::any(),
+                Argument::that(function ($arg) use (&$patchersFound) {
+                    $patchersFound = $arg;
+
+                    return true;
+                }),
+                Argument::any()
+            )
+            ->shouldBeCalled();
+
+        $this->appTester->run($input);
+
+        $this->assertCount(0, $patchersFound);
+
+        $this->handleProphecy->__invoke(Argument::cetera())->shouldHaveBeenCalledTimes(1);
+    }
+
+    public function test_throws_an_error_if_patch_file_returns_an_array_with_invalid_values()
+    {
+        chdir(escape_path(self::FIXTURE_PATH.'/set009'));
+
+        $input = [
+            'add-prefix',
+            '--prefix' => 'MyPrefix',
+            'paths' => [
+                escape_path('/path/to/dir1'),
+            ],
+        ];
+
+        $this->fileSystemProphecy->isAbsolutePath('unknown')->willReturn(false);
+        $this->fileSystemProphecy->isAbsolutePath(Argument::cetera())->willReturn(true);
+        $this->fileSystemProphecy->exists('build')->willReturn(false);
+
+        $this->handleProphecy->__invoke(Argument::cetera())->shouldNotBeCalled();
+
+        try {
+            $this->appTester->run($input);
+
+            $this->fail('Expected exception to be thrown.');
+        } catch (RuntimeException $exception) {
+            $patchFile = escape_path($this->cwd.'/unknown');
+
+            $this->assertSame(
+                'Expected patchers to be an array of callables, the "0" element is not.',
+                $exception->getMessage()
+            );
+            $this->assertSame(0, $exception->getCode());
+            $this->assertNull($exception->getPrevious());
+        }
+    }
+
     public function provideEmptyPrefixes()
     {
         yield 'empty' => [''];
diff --git a/tests/Handler/HandleAddPrefixTest.php b/tests/Handler/HandleAddPrefixTest.php
index fded272b..b65d7499 100644
--- a/tests/Handler/HandleAddPrefixTest.php
+++ b/tests/Handler/HandleAddPrefixTest.php
@@ -24,6 +24,7 @@
 use Prophecy\Argument;
 use Prophecy\Prophecy\ObjectProphecy;
 use Throwable;
+use function Humbug\PhpScoper\create_fake_patcher;
 use function Humbug\PhpScoper\escape_path;
 use function Humbug\PhpScoper\make_tmp_dir;
 use function Humbug\PhpScoper\remove_dir;
@@ -108,6 +109,8 @@ function (string $relativePath) {
 
         $outputPath = $this->tmp;
 
+        $patchers = [create_fake_patcher()];
+
         /** @var ConsoleLogger $logger */
         $logger = $this->loggerProphecy->reveal();
 
@@ -115,14 +118,14 @@ function (string $relativePath) {
             $filePath = realpath(escape_path(self::FIXTURE_PATH_000.$fileContent));
             $this->assertNotFalse($filePath, 'Type check.');
 
-            $this->scoperProphecy->scope($filePath, $prefix)->shouldBeCalled();
+            $this->scoperProphecy->scope($filePath, $prefix, $patchers)->shouldBeCalled();
 
             $this->loggerProphecy->outputSuccess($filePath)->shouldBeCalled();
         }
 
         $this->loggerProphecy->outputFileCount(count($expected))->shouldBeCalled();
 
-        $this->handle->__invoke($prefix, $paths, $outputPath, $logger);
+        $this->handle->__invoke($prefix, $paths, $outputPath, $patchers, $logger);
 
         $this->scoperProphecy->scope(Argument::cetera())->shouldHaveBeenCalledTimes(count($expected));
 
@@ -140,6 +143,8 @@ public function test_replaces_the_content_of_the_files_with_the_scoped_content()
 
         $outputPath = $this->tmp;
 
+        $patchers = [create_fake_patcher()];
+
         /** @var ConsoleLogger $logger */
         $logger = $this->loggerProphecy->reveal();
 
@@ -152,9 +157,9 @@ public function test_replaces_the_content_of_the_files_with_the_scoped_content()
 
 PHP;
 
-        $this->scoperProphecy->scope(Argument::any(), $prefix)->willReturn($expected);
+        $this->scoperProphecy->scope(Argument::any(), $prefix, $patchers)->willReturn($expected);
 
-        $this->handle->__invoke($prefix, $paths, $outputPath, $logger);
+        $this->handle->__invoke($prefix, $paths, $outputPath, $patchers, $logger);
 
         $actual = file_get_contents(
             escape_path($this->tmp.'/file.php')
@@ -173,13 +178,15 @@ public function test_cannot_collect_files_from_unknown_paths()
 
         $outputPath = $this->tmp.DIRECTORY_SEPARATOR.'output-dir';
 
+        $patchers = [create_fake_patcher()];
+
         /** @var ConsoleLogger $logger */
         $logger = $this->loggerProphecy->reveal();
 
         $this->scoperProphecy->scope(Argument::cetera())->shouldNotBeCalled();
 
         try {
-            $this->handle->__invoke($prefix, $paths, $outputPath, $logger);
+            $this->handle->__invoke($prefix, $paths, $outputPath, $patchers, $logger);
 
             $this->fail('Expected exception to be thrown.');
         } catch (RuntimeException $exception) {
@@ -204,16 +211,18 @@ public function test_removes_scoped_files_on_failure()
 
         $outputPath = $this->tmp.DIRECTORY_SEPARATOR.'output-dir';
 
+        $patchers = [create_fake_patcher()];
+
         /** @var ConsoleLogger $logger */
         $logger = $this->loggerProphecy->reveal();
 
         $this->scoperProphecy
-            ->scope(Argument::any(), $prefix)
+            ->scope(Argument::any(), $prefix, $patchers)
             ->willThrow($error = new Error('Unknown error'))
         ;
 
         try {
-            $this->handle->__invoke($prefix, $paths, $outputPath, $logger);
+            $this->handle->__invoke($prefix, $paths, $outputPath, $patchers, $logger);
 
             $this->fail('Expected exception to be thrown.');
         } catch (Throwable $throwable) {
@@ -233,16 +242,18 @@ public function test_throws_an_error_when_cannot_parse_a_file()
 
         $outputPath = $this->tmp.DIRECTORY_SEPARATOR.'output-dir';
 
+        $patchers = [create_fake_patcher()];
+
         /** @var ConsoleLogger $logger */
         $logger = $this->loggerProphecy->reveal();
 
         $this->scoperProphecy
-            ->scope(Argument::any(), $prefix)
+            ->scope(Argument::any(), $prefix, $patchers)
             ->willThrow($error = new PhpParserError('Could not parse file'))
         ;
 
         try {
-            $this->handle->__invoke($prefix, $paths, $outputPath, $logger);
+            $this->handle->__invoke($prefix, $paths, $outputPath, $patchers, $logger);
 
             $this->fail('Expected exception to be thrown.');
         } catch (ParsingException $exception) {
diff --git a/tests/Scoper/Composer/InstalledPackagesScoperTest.php b/tests/Scoper/Composer/InstalledPackagesScoperTest.php
index 633f82c3..f08d7dfd 100644
--- a/tests/Scoper/Composer/InstalledPackagesScoperTest.php
+++ b/tests/Scoper/Composer/InstalledPackagesScoperTest.php
@@ -19,6 +19,7 @@
 use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
 use Prophecy\Prophecy\ObjectProphecy;
+use function Humbug\PhpScoper\create_fake_patcher;
 use function Humbug\PhpScoper\escape_path;
 use function Humbug\PhpScoper\make_tmp_dir;
 use function Humbug\PhpScoper\remove_dir;
@@ -70,6 +71,7 @@ public function test_delegates_scoping_to_the_decorated_scoper_if_is_not_a_insta
     {
         $filePath = escape_path($this->tmp.'/file.php');
         $prefix = 'Humbug';
+        $patchers = [create_fake_patcher()];
 
         touch($filePath);
         file_put_contents($filePath, '');
@@ -77,7 +79,7 @@ public function test_delegates_scoping_to_the_decorated_scoper_if_is_not_a_insta
         /** @var Scoper|ObjectProphecy $decoratedScoperProphecy */
         $decoratedScoperProphecy = $this->prophesize(Scoper::class);
         $decoratedScoperProphecy
-            ->scope($filePath, $prefix)
+            ->scope($filePath, $prefix, $patchers)
             ->willReturn(
                 $expected = 'Scoped content'
             )
@@ -87,7 +89,7 @@ public function test_delegates_scoping_to_the_decorated_scoper_if_is_not_a_insta
 
         $scoper = new InstalledPackagesScoper($decoratedScoper);
 
-        $actual = $scoper->scope($filePath, $prefix);
+        $actual = $scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
 
@@ -105,7 +107,10 @@ public function test_it_prefixes_the_composer_autoloaders(string $fileContent, s
 
         $scoper = new InstalledPackagesScoper(new FakeScoper());
 
-        $actual = $scoper->scope($filePath, 'Foo');
+        $prefix = 'Foo';
+        $patchers = [create_fake_patcher()];
+
+        $actual = $scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
     }
diff --git a/tests/Scoper/Composer/JsonFileScoperTest.php b/tests/Scoper/Composer/JsonFileScoperTest.php
index c71cf5b9..6a26108f 100644
--- a/tests/Scoper/Composer/JsonFileScoperTest.php
+++ b/tests/Scoper/Composer/JsonFileScoperTest.php
@@ -19,6 +19,7 @@
 use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
 use Prophecy\Prophecy\ObjectProphecy;
+use function Humbug\PhpScoper\create_fake_patcher;
 use function Humbug\PhpScoper\escape_path;
 use function Humbug\PhpScoper\make_tmp_dir;
 use function Humbug\PhpScoper\remove_dir;
@@ -70,6 +71,7 @@ public function test_delegates_scoping_to_the_decorated_scoper_if_is_not_a_compo
     {
         $filePath = escape_path($this->tmp.'/file.php');
         $prefix = 'Humbug';
+        $patchers = [create_fake_patcher()];
 
         touch($filePath);
         file_put_contents($filePath, '');
@@ -77,7 +79,7 @@ public function test_delegates_scoping_to_the_decorated_scoper_if_is_not_a_compo
         /** @var Scoper|ObjectProphecy $decoratedScoperProphecy */
         $decoratedScoperProphecy = $this->prophesize(Scoper::class);
         $decoratedScoperProphecy
-            ->scope($filePath, $prefix)
+            ->scope($filePath, $prefix, $patchers)
             ->willReturn(
                 $expected = 'Scoped content'
             )
@@ -87,7 +89,7 @@ public function test_delegates_scoping_to_the_decorated_scoper_if_is_not_a_compo
 
         $scoper = new JsonFileScoper($decoratedScoper);
 
-        $actual = $scoper->scope($filePath, $prefix);
+        $actual = $scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
 
@@ -104,7 +106,10 @@ public function test_it_prefixes_the_composer_autoloaders(string $fileContent, s
 
         $scoper = new JsonFileScoper(new FakeScoper());
 
-        $actual = $scoper->scope($filePath, 'Foo');
+        $prefix = 'Foo';
+        $patchers = [create_fake_patcher()];
+
+        $actual = $scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
     }
diff --git a/tests/Scoper/FakeScoper.php b/tests/Scoper/FakeScoper.php
index 3c4e7838..4599f074 100644
--- a/tests/Scoper/FakeScoper.php
+++ b/tests/Scoper/FakeScoper.php
@@ -21,7 +21,7 @@ final class FakeScoper implements Scoper
     /**
      * @inheritdoc
      */
-    public function scope(string $filePath, string $prefix): string
+    public function scope(string $filePath, string $prefix, array $patchers): string
     {
         throw new \LogicException();
     }
diff --git a/tests/Scoper/NullScoperTest.php b/tests/Scoper/NullScoperTest.php
index 9f8faf53..6f6a64f8 100644
--- a/tests/Scoper/NullScoperTest.php
+++ b/tests/Scoper/NullScoperTest.php
@@ -16,6 +16,7 @@
 
 use Humbug\PhpScoper\Scoper;
 use PHPUnit\Framework\TestCase;
+use function Humbug\PhpScoper\create_fake_patcher;
 use function Humbug\PhpScoper\escape_path;
 use function Humbug\PhpScoper\make_tmp_dir;
 use function Humbug\PhpScoper\remove_dir;
@@ -73,9 +74,11 @@ public function test_returns_the_file_content_unchanged()
 
         $prefix = 'Humbug';
 
+        $patchers = [create_fake_patcher()];
+
         $scoper = new NullScoper();
 
-        $actual = $scoper->scope($filePath, $prefix);
+        $actual = $scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
     }
diff --git a/tests/Scoper/PhpScoperTest.php b/tests/Scoper/PhpScoperTest.php
index acf75e4d..99a594b4 100644
--- a/tests/Scoper/PhpScoperTest.php
+++ b/tests/Scoper/PhpScoperTest.php
@@ -20,6 +20,7 @@
 use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
 use Prophecy\Prophecy\ObjectProphecy;
+use function Humbug\PhpScoper\create_fake_patcher;
 use function Humbug\PhpScoper\create_parser;
 use function Humbug\PhpScoper\escape_path;
 use function Humbug\PhpScoper\make_tmp_dir;
@@ -94,8 +95,8 @@ public function test_is_a_Scoper()
     public function test_can_scope_a_PHP_file()
     {
         $prefix = 'Humbug';
-
         $filePath = escape_path($this->tmp.'/file.php');
+        $patchers = [create_fake_patcher()];
 
         $content = <<<'PHP'
 echo "Humbug!";
@@ -109,7 +110,7 @@ public function test_can_scope_a_PHP_file()
 
 PHP;
 
-        $actual = $this->scoper->scope($filePath, $prefix);
+        $actual = $this->scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
     }
@@ -118,9 +119,10 @@ public function test_does_not_scope_file_if_is_not_a_PHP_file()
     {
         $filePath = 'file.yaml';
         $prefix = 'Humbug';
+        $patchers = [create_fake_patcher()];
 
         $this->decoratedScoperProphecy
-            ->scope($filePath, $prefix)
+            ->scope($filePath, $prefix, $patchers)
             ->willReturn(
                 $expected = 'Scoped content'
             )
@@ -131,7 +133,7 @@ public function test_does_not_scope_file_if_is_not_a_PHP_file()
             $this->decoratedScoper
         );
 
-        $actual = $scoper->scope($filePath, $prefix);
+        $actual = $scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
 
@@ -141,8 +143,8 @@ public function test_does_not_scope_file_if_is_not_a_PHP_file()
     public function test_can_scope_PHP_binary_files()
     {
         $prefix = 'Humbug';
-
         $filePath = escape_path($this->tmp.'/hello');
+        $patchers = [create_fake_patcher()];
 
         $content = <<<'PHP'
 #!/usr/bin/env php
@@ -161,7 +163,7 @@ public function test_can_scope_PHP_binary_files()
 
 PHP;
 
-        $actual = $this->scoper->scope($filePath, $prefix);
+        $actual = $this->scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
     }
@@ -172,6 +174,8 @@ public function test_does_not_scope_a_non_PHP_binary_files()
 
         $filePath = escape_path($this->tmp.'/hello');
 
+        $patchers = [create_fake_patcher()];
+
         $content = <<<'PHP'
 #!/usr/bin/env bash
 <?php
@@ -183,7 +187,7 @@ public function test_does_not_scope_a_non_PHP_binary_files()
         file_put_contents($filePath, $content);
 
         $this->decoratedScoperProphecy
-            ->scope($filePath, $prefix)
+            ->scope($filePath, $prefix, $patchers)
             ->willReturn(
                 $expected = 'Scoped content'
             )
@@ -194,7 +198,7 @@ public function test_does_not_scope_a_non_PHP_binary_files()
             $this->decoratedScoper
         );
 
-        $actual = $scoper->scope($filePath, $prefix);
+        $actual = $scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
 
@@ -215,9 +219,10 @@ public function test_cannot_scope_an_invalid_PHP_file()
         file_put_contents($filePath, $content);
 
         $prefix = 'Humbug';
+        $patchers = [create_fake_patcher()];
 
         try {
-            $this->scoper->scope($filePath, $prefix);
+            $this->scoper->scope($filePath, $prefix, $patchers);
 
             $this->fail('Expected exception to have been thrown.');
         } catch (PhpParserError $error) {
@@ -240,7 +245,9 @@ public function test_can_scope_valid_files(string $content, string $prefix, stri
         touch($filePath);
         file_put_contents($filePath, $content);
 
-        $actual = $this->scoper->scope($filePath, $prefix);
+        $patchers = [create_fake_patcher()];
+
+        $actual = $this->scoper->scope($filePath, $prefix, $patchers);
 
         $this->assertSame($expected, $actual);
     }
diff --git a/tests/functions.php b/tests/functions.php
index 488b4eea..9b52a4cb 100644
--- a/tests/functions.php
+++ b/tests/functions.php
@@ -14,6 +14,8 @@
 
 namespace Humbug\PhpScoper;
 
+use Closure;
+use LogicException;
 use Symfony\Component\Filesystem\Filesystem;
 
 /**
@@ -63,3 +65,10 @@ function remove_dir(string $path)
         (new Filesystem())->remove($path);
     }
 }
+
+function create_fake_patcher(): Closure
+{
+    return function () {
+        throw new LogicException('Did not expect to be called');
+    };
+}