From 15d05f8d2edcb50e1c1b37786a48cb656c6268ac Mon Sep 17 00:00:00 2001
From: alexpozzi <alexpozzi@users.noreply.github.com>
Date: Fri, 7 Feb 2020 15:45:37 +0100
Subject: [PATCH] phpstan level 8 CI check

---
 phpstan.neon                               |   4 +-
 src/Knp/Snappy/AbstractGenerator.php       | 171 +++++++++++++--------
 src/Knp/Snappy/GeneratorInterface.php      |   8 +-
 src/Knp/Snappy/Image.php                   |   4 +-
 src/Knp/Snappy/Pdf.php                     |  17 +-
 tests/Knp/Snappy/AbstractGeneratorTest.php |  58 +++----
 tests/Knp/Snappy/ImageTest.php             |   2 +-
 tests/Knp/Snappy/PdfTest.php               |  27 ++--
 8 files changed, 177 insertions(+), 114 deletions(-)

diff --git a/phpstan.neon b/phpstan.neon
index c51e18d0..f99e8107 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -2,11 +2,13 @@ includes:
     - vendor/phpstan/phpstan-phpunit/extension.neon
 
 parameters:
-    level: 4
+    level: 8
     paths:
         - src/
         - tests/
     inferPrivatePropertyTypeFromConstructor: true
     reportUnmatchedIgnoredErrors: false
+    checkMissingIterableValueType: false
     ignoreErrors:
         - "#^Call to an undefined static method #"
+        - "#^Parameter \\#1 \\$command of class Symfony\\\\Component\\\\Process\\\\Process constructor expects array, string given\\.$#"
diff --git a/src/Knp/Snappy/AbstractGenerator.php b/src/Knp/Snappy/AbstractGenerator.php
index 8f878e14..e647f182 100644
--- a/src/Knp/Snappy/AbstractGenerator.php
+++ b/src/Knp/Snappy/AbstractGenerator.php
@@ -17,10 +17,29 @@
  */
 abstract class AbstractGenerator implements GeneratorInterface, LoggerAwareInterface
 {
+    /**
+     * @var string|null
+     */
     private $binary;
+
+    /**
+     * @var array
+     */
     private $options = [];
+
+    /**
+     * @var array|null
+     */
     private $env;
-    private $timeout = false;
+
+    /**
+     * @var int|null
+     */
+    private $timeout;
+
+    /**
+     * @var string
+     */
     private $defaultExtension;
 
     /**
@@ -39,11 +58,11 @@ abstract class AbstractGenerator implements GeneratorInterface, LoggerAwareInter
     private $logger;
 
     /**
-     * @param string $binary
-     * @param array  $options
-     * @param array  $env
+     * @param string|null $binary
+     * @param array       $options
+     * @param array|null  $env
      */
-    public function __construct($binary, array $options = [], array $env = null)
+    public function __construct(string $binary = null, array $options = [], array $env = null)
     {
         $this->configure();
 
@@ -67,9 +86,11 @@ public function __destruct()
      *
      * @param LoggerInterface $logger
      */
-    public function setLogger(LoggerInterface $logger)
+    public function setLogger(LoggerInterface $logger): self
     {
         $this->logger = $logger;
+
+        return $this;
     }
 
     /**
@@ -77,7 +98,7 @@ public function setLogger(LoggerInterface $logger)
      *
      * @see AbstractGenerator::addOption()
      */
-    abstract protected function configure();
+    abstract protected function configure(): void;
 
     /**
      * Sets the default extension.
@@ -85,9 +106,11 @@ abstract protected function configure();
      *
      * @param string $defaultExtension
      */
-    public function setDefaultExtension($defaultExtension)
+    public function setDefaultExtension(string $defaultExtension): self
     {
         $this->defaultExtension = $defaultExtension;
+
+        return $this;
     }
 
     /**
@@ -95,7 +118,7 @@ public function setDefaultExtension($defaultExtension)
      *
      * @return string
      */
-    public function getDefaultExtension()
+    public function getDefaultExtension(): string
     {
         return $this->defaultExtension;
     }
@@ -109,7 +132,7 @@ public function getDefaultExtension()
      *
      * @throws \InvalidArgumentException
      */
-    public function setOption($name, $value)
+    public function setOption(string $name, $value): self
     {
         if (!array_key_exists($name, $this->options)) {
             throw new \InvalidArgumentException(sprintf('The option \'%s\' does not exist.', $name));
@@ -118,16 +141,20 @@ public function setOption($name, $value)
         $this->options[$name] = $value;
 
         $this->logger->debug(sprintf('Set option "%s".', $name), ['value' => $value]);
+
+        return $this;
     }
 
     /**
      * Sets the timeout.
      *
-     * @param int $timeout The timeout to set
+     * @param int|null $timeout The timeout to set
      */
-    public function setTimeout($timeout)
+    public function setTimeout(?int $timeout): self
     {
         $this->timeout = $timeout;
+
+        return $this;
     }
 
     /**
@@ -135,11 +162,13 @@ public function setTimeout($timeout)
      *
      * @param array $options An associative array of options as name/value
      */
-    public function setOptions(array $options)
+    public function setOptions(array $options): self
     {
         foreach ($options as $name => $value) {
             $this->setOption($name, $value);
         }
+
+        return $this;
     }
 
     /**
@@ -147,7 +176,7 @@ public function setOptions(array $options)
      *
      * @return array
      */
-    public function getOptions()
+    public function getOptions(): array
     {
         return $this->options;
     }
@@ -155,14 +184,8 @@ public function getOptions()
     /**
      * {@inheritdoc}
      */
-    public function generate($input, $output, array $options = [], $overwrite = false)
+    public function generate($input, string $output, array $options = [], bool $overwrite = false): void
     {
-        if (null === $this->binary) {
-            throw new \LogicException(
-                'You must define a binary prior to conversion.'
-            );
-        }
-
         $this->prepareOutput($output, $overwrite);
 
         $command = $this->getCommand($input, $output, $options);
@@ -200,7 +223,7 @@ public function generate($input, $output, array $options = [], $overwrite = fals
     /**
      * {@inheritdoc}
      */
-    public function generateFromHtml($html, $output, array $options = [], $overwrite = false)
+    public function generateFromHtml($html, string $output, array $options = [], bool $overwrite = false): void
     {
         $fileNames = [];
         if (is_array($html)) {
@@ -217,21 +240,19 @@ public function generateFromHtml($html, $output, array $options = [], $overwrite
     /**
      * {@inheritdoc}
      */
-    public function getOutput($input, array $options = [])
+    public function getOutput($input, array $options = []): string
     {
         $filename = $this->createTemporaryFile(null, $this->getDefaultExtension());
 
         $this->generate($input, $filename, $options);
 
-        $result = $this->getFileContents($filename);
-
-        return $result;
+        return $this->getFileContents($filename);
     }
 
     /**
      * {@inheritdoc}
      */
-    public function getOutputFromHtml($html, array $options = [])
+    public function getOutputFromHtml($html, array $options = []): string
     {
         $fileNames = [];
         if (is_array($html)) {
@@ -242,27 +263,27 @@ public function getOutputFromHtml($html, array $options = [])
             $fileNames[] = $this->createTemporaryFile($html, 'html');
         }
 
-        $result = $this->getOutput($fileNames, $options);
-
-        return $result;
+        return $this->getOutput($fileNames, $options);
     }
 
     /**
      * Defines the binary.
      *
-     * @param string $binary The path/name of the binary
+     * @param string|null $binary The path/name of the binary
      */
-    public function setBinary($binary)
+    public function setBinary(?string $binary): self
     {
         $this->binary = $binary;
+
+        return $this;
     }
 
     /**
      * Returns the binary.
      *
-     * @return string
+     * @return string|null
      */
-    public function getBinary()
+    public function getBinary(): ?string
     {
         return $this->binary;
     }
@@ -277,8 +298,14 @@ public function getBinary()
      *
      * @return string
      */
-    public function getCommand($input, $output, array $options = [])
+    public function getCommand($input, string $output, array $options = []): string
     {
+        if (null === $this->binary) {
+            throw new \LogicException(
+                'You must define a binary prior to conversion.'
+            );
+        }
+
         $options = $this->mergeOptions($options);
 
         return $this->buildCommand($this->binary, $input, $output, $options);
@@ -292,13 +319,15 @@ public function getCommand($input, $output, array $options = [])
      *
      * @throws \InvalidArgumentException
      */
-    protected function addOption($name, $default = null)
+    protected function addOption(string $name, $default = null): self
     {
         if (array_key_exists($name, $this->options)) {
             throw new \InvalidArgumentException(sprintf('The option \'%s\' already exists.', $name));
         }
 
         $this->options[$name] = $default;
+
+        return $this;
     }
 
     /**
@@ -306,11 +335,13 @@ protected function addOption($name, $default = null)
      *
      * @param array $options
      */
-    protected function addOptions(array $options)
+    protected function addOptions(array $options): self
     {
         foreach ($options as $name => $default) {
             $this->addOption($name, $default);
         }
+
+        return $this;
     }
 
     /**
@@ -323,7 +354,7 @@ protected function addOptions(array $options)
      *
      * @return array
      */
-    protected function mergeOptions(array $options)
+    protected function mergeOptions(array $options): array
     {
         $mergedOptions = $this->options;
 
@@ -346,7 +377,7 @@ protected function mergeOptions(array $options)
      *
      * @throws \RuntimeException if the output file generation failed
      */
-    protected function checkOutput($output, $command)
+    protected function checkOutput(string $output, string $command): void
     {
         // the output file must exist
         if (!$this->fileExists($output)) {
@@ -377,7 +408,7 @@ protected function checkOutput($output, $command)
      *
      * @throws \RuntimeException if the output file generation failed
      */
-    protected function checkProcessStatus($status, $stdout, $stderr, $command)
+    protected function checkProcessStatus(int $status, string $stdout, string $stderr, string $command): void
     {
         if (0 !== $status and '' !== $stderr) {
             throw new \RuntimeException(sprintf(
@@ -397,12 +428,12 @@ protected function checkProcessStatus($status, $stdout, $stderr, $command)
      * Creates a temporary file.
      * The file is not created if the $content argument is null.
      *
-     * @param string $content   Optional content for the temporary file
-     * @param string $extension An optional extension for the filename
+     * @param string|null $content   Optional content for the temporary file
+     * @param string|null $extension An optional extension for the filename
      *
      * @return string The filename
      */
-    protected function createTemporaryFile($content = null, $extension = null)
+    protected function createTemporaryFile(?string $content = null, ?string $extension = null): string
     {
         $dir = rtrim($this->getTemporaryFolder(), DIRECTORY_SEPARATOR);
 
@@ -449,7 +480,7 @@ public function removeTemporaryFiles(): void
      *
      * @return string
      */
-    protected function buildCommand($binary, $input, $output, array $options = [])
+    protected function buildCommand(string $binary, $input, string $output, array $options = []): string
     {
         $command = $binary;
         $escapedBinary = escapeshellarg($binary);
@@ -509,7 +540,7 @@ protected function buildCommand($binary, $input, $output, array $options = [])
      *
      * @return bool
      */
-    protected function isAssociativeArray(array $array)
+    protected function isAssociativeArray(array $array): bool
     {
         return (bool) count(array_filter(array_keys($array), 'is_string'));
     }
@@ -522,7 +553,7 @@ protected function isAssociativeArray(array $array)
      *
      * @return array(status, stdout, stderr)
      */
-    protected function executeCommand($command)
+    protected function executeCommand(string $command): array
     {
         if (method_exists(Process::class, 'fromShellCommandline')) {
             $process = Process::fromShellCommandline($command, null, $this->env);
@@ -530,7 +561,7 @@ protected function executeCommand($command)
             $process = new Process($command, null, $this->env);
         }
 
-        if (false !== $this->timeout) {
+        if (null !== $this->timeout) {
             $process->setTimeout($this->timeout);
         }
 
@@ -554,7 +585,7 @@ protected function executeCommand($command)
      * @throws \RuntimeException
      * @throws \InvalidArgumentException
      */
-    protected function prepareOutput($filename, $overwrite)
+    protected function prepareOutput(string $filename, bool $overwrite): void
     {
         $directory = dirname($filename);
 
@@ -589,7 +620,7 @@ protected function prepareOutput($filename, $overwrite)
      *
      * @return string
      */
-    public function getTemporaryFolder()
+    public function getTemporaryFolder(): string
     {
         if ($this->temporaryFolder === null) {
             return sys_get_temp_dir();
@@ -605,7 +636,7 @@ public function getTemporaryFolder()
      *
      * @return $this
      */
-    public function setTemporaryFolder($temporaryFolder)
+    public function setTemporaryFolder(string $temporaryFolder): self
     {
         $this->temporaryFolder = $temporaryFolder;
 
@@ -619,9 +650,18 @@ public function setTemporaryFolder($temporaryFolder)
      *
      * @return string
      */
-    protected function getFileContents($filename)
+    protected function getFileContents(string $filename): string
     {
-        return file_get_contents($filename);
+        $fileContent = file_get_contents($filename);
+
+        if (false === $fileContent) {
+            throw new \RuntimeException(sprintf(
+                'Could not read file \'%s\' content.',
+                $filename
+            ));
+        }
+
+        return $fileContent;
     }
 
     /**
@@ -631,7 +671,7 @@ protected function getFileContents($filename)
      *
      * @return bool
      */
-    protected function fileExists($filename)
+    protected function fileExists(string $filename): bool
     {
         return file_exists($filename);
     }
@@ -643,7 +683,7 @@ protected function fileExists($filename)
      *
      * @return bool
      */
-    protected function isFile($filename)
+    protected function isFile(string $filename): bool
     {
         return strlen($filename) <= PHP_MAXPATHLEN && is_file($filename);
     }
@@ -653,11 +693,20 @@ protected function isFile($filename)
      *
      * @param string $filename
      *
-     * @return int or FALSE on failure
+     * @return int
      */
-    protected function filesize($filename)
+    protected function filesize(string $filename): int
     {
-        return filesize($filename);
+        $filesize = filesize($filename);
+
+        if (false === $filesize) {
+            throw new \RuntimeException(sprintf(
+                'Could not read file \'%s\' size.',
+                $filename
+            ));
+        }
+
+        return $filesize;
     }
 
     /**
@@ -667,7 +716,7 @@ protected function filesize($filename)
      *
      * @return bool
      */
-    protected function unlink($filename)
+    protected function unlink(string $filename): bool
     {
         return $this->fileExists($filename) ? unlink($filename) : false;
     }
@@ -679,7 +728,7 @@ protected function unlink($filename)
      *
      * @return bool
      */
-    protected function isDir($filename)
+    protected function isDir(string $filename): bool
     {
         return is_dir($filename);
     }
@@ -691,7 +740,7 @@ protected function isDir($filename)
      *
      * @return bool
      */
-    protected function mkdir($pathname)
+    protected function mkdir(string $pathname): bool
     {
         return mkdir($pathname, 0777, true);
     }
@@ -701,7 +750,7 @@ protected function mkdir($pathname)
      *
      * @return void
      */
-    public function resetOptions()
+    public function resetOptions(): void
     {
         $this->options = [];
         $this->configure();
diff --git a/src/Knp/Snappy/GeneratorInterface.php b/src/Knp/Snappy/GeneratorInterface.php
index cd049dbe..5a65e7e8 100644
--- a/src/Knp/Snappy/GeneratorInterface.php
+++ b/src/Knp/Snappy/GeneratorInterface.php
@@ -19,7 +19,7 @@ interface GeneratorInterface
      * @param array        $options   An array of options for this generation only
      * @param bool         $overwrite Overwrite the file if it exists. If not, throw a FileAlreadyExistsException
      */
-    public function generate($input, $output, array $options = [], $overwrite = false);
+    public function generate($input, string $output, array $options = [], bool $overwrite = false): void;
 
     /**
      * Generates the output media file from the given HTML.
@@ -29,7 +29,7 @@ public function generate($input, $output, array $options = [], $overwrite = fals
      * @param array        $options   An array of options for this generation only
      * @param bool         $overwrite Overwrite the file if it exists. If not, throw a FileAlreadyExistsException
      */
-    public function generateFromHtml($html, $output, array $options = [], $overwrite = false);
+    public function generateFromHtml($html, string $output, array $options = [], bool $overwrite = false): void;
 
     /**
      * Returns the output of the media generated from the specified input HTML
@@ -40,7 +40,7 @@ public function generateFromHtml($html, $output, array $options = [], $overwrite
      *
      * @return string
      */
-    public function getOutput($input, array $options = []);
+    public function getOutput($input, array $options = []): string;
 
     /**
      * Returns the output of the media generated from the given HTML.
@@ -50,5 +50,5 @@ public function getOutput($input, array $options = []);
      *
      * @return string
      */
-    public function getOutputFromHtml($html, array $options = []);
+    public function getOutputFromHtml($html, array $options = []): string;
 }
diff --git a/src/Knp/Snappy/Image.php b/src/Knp/Snappy/Image.php
index 60c422fe..78f41761 100644
--- a/src/Knp/Snappy/Image.php
+++ b/src/Knp/Snappy/Image.php
@@ -14,7 +14,7 @@ class Image extends AbstractGenerator
     /**
      * {@inheritdoc}
      */
-    public function __construct($binary = null, array $options = [], array $env = null)
+    public function __construct(string $binary = null, array $options = [], array $env = null)
     {
         $this->setDefaultExtension('jpg');
 
@@ -24,7 +24,7 @@ public function __construct($binary = null, array $options = [], array $env = nu
     /**
      * {@inheritdoc}
      */
-    protected function configure()
+    protected function configure(): void
     {
         $this->addOptions([
             'allow'                        => null,    // Allow the file or files from the specified folder to be loaded (repeatable)
diff --git a/src/Knp/Snappy/Pdf.php b/src/Knp/Snappy/Pdf.php
index 90a5c743..9cc22861 100644
--- a/src/Knp/Snappy/Pdf.php
+++ b/src/Knp/Snappy/Pdf.php
@@ -11,12 +11,15 @@
  */
 class Pdf extends AbstractGenerator
 {
+    /**
+     * @var array
+     */
     protected $optionsWithContentCheck = [];
 
     /**
      * {@inheritdoc}
      */
-    public function __construct($binary = null, array $options = [], array $env = null)
+    public function __construct(string $binary = null, array $options = [], array $env = null)
     {
         $this->setDefaultExtension('pdf');
         $this->setOptionsWithContentCheck();
@@ -31,7 +34,7 @@ public function __construct($binary = null, array $options = [], array $env = nu
      *
      * @return array $options Transformed options
      */
-    protected function handleOptions(array $options = [])
+    protected function handleOptions(array $options = []): array
     {
         foreach ($options as $option => $value) {
             if (null === $value) {
@@ -56,7 +59,7 @@ protected function handleOptions(array $options = [])
     /**
      * {@inheritdoc}
      */
-    public function generate($input, $output, array $options = [], $overwrite = false)
+    public function generate($input, string $output, array $options = [], bool $overwrite = false): void
     {
         $options = $this->handleOptions($this->mergeOptions($options));
 
@@ -70,7 +73,7 @@ public function generate($input, $output, array $options = [], $overwrite = fals
      *
      * @return bool
      */
-    protected function isOptionUrl($option)
+    protected function isOptionUrl($option): bool
     {
         return (bool) filter_var($option, FILTER_VALIDATE_URL);
     }
@@ -78,7 +81,7 @@ protected function isOptionUrl($option)
     /**
      * {@inheritdoc}
      */
-    protected function configure()
+    protected function configure(): void
     {
         $this->addOptions([
             // Global options
@@ -226,7 +229,7 @@ protected function configure()
     /**
      * Array with options which require to store the content of the option before passing it to wkhtmltopdf.
      */
-    protected function setOptionsWithContentCheck()
+    protected function setOptionsWithContentCheck(): self
     {
         $this->optionsWithContentCheck = [
             'header-html'    => 'html',
@@ -234,5 +237,7 @@ protected function setOptionsWithContentCheck()
             'cover'          => 'html',
             'xsl-style-sheet'=> 'xsl',
         ];
+
+        return $this;
     }
 }
diff --git a/tests/Knp/Snappy/AbstractGeneratorTest.php b/tests/Knp/Snappy/AbstractGeneratorTest.php
index a6a8989b..df8c28df 100644
--- a/tests/Knp/Snappy/AbstractGeneratorTest.php
+++ b/tests/Knp/Snappy/AbstractGeneratorTest.php
@@ -8,7 +8,7 @@
 
 class AbstractGeneratorTest extends TestCase
 {
-    public function testAddOption()
+    public function testAddOption(): void
     {
         $media = $this->getMockForAbstractClass(AbstractGenerator::class, [], '', false);
 
@@ -41,7 +41,7 @@ public function testAddOption()
         }
     }
 
-    public function testAddOptions()
+    public function testAddOptions(): void
     {
         $media = $this->getMockForAbstractClass(AbstractGenerator::class, [], '', false);
 
@@ -83,7 +83,7 @@ public function testAddOptions()
         }
     }
 
-    public function testSetOption()
+    public function testSetOption(): void
     {
         $media = $this
             ->getMockBuilder(AbstractGenerator::class)
@@ -122,7 +122,7 @@ public function testSetOption()
         }
     }
 
-    public function testSetOptions()
+    public function testSetOptions(): void
     {
         $media = $this
             ->getMockBuilder(AbstractGenerator::class)
@@ -162,7 +162,7 @@ public function testSetOptions()
         }
     }
 
-    public function testGenerate()
+    public function testGenerate(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -235,7 +235,7 @@ public function testGenerate()
         $media->generate('the_input_file', 'the_output_file', ['foo' => 'bar']);
     }
 
-    public function testFailingGenerate()
+    public function testFailingGenerate(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -304,7 +304,7 @@ public function testFailingGenerate()
         $media->generate('the_input_file', 'the_output_file', ['foo' => 'bar']);
     }
 
-    public function testGenerateFromHtml()
+    public function testGenerateFromHtml(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -339,7 +339,7 @@ public function testGenerateFromHtml()
         $media->generateFromHtml('<html>foo</html>', 'the_output_file', ['foo' => 'bar']);
     }
 
-    public function testGenerateFromHtmlWithHtmlArray()
+    public function testGenerateFromHtmlWithHtmlArray(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -373,7 +373,7 @@ public function testGenerateFromHtmlWithHtmlArray()
         $media->generateFromHtml(['<html>foo</html>'], 'the_output_file', ['foo' => 'bar']);
     }
 
-    public function testGetOutput()
+    public function testGetOutput(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -426,7 +426,7 @@ public function testGetOutput()
         $this->assertEquals('the file contents', $media->getOutput('the_input_file', ['foo' => 'bar']));
     }
 
-    public function testGetOutputFromHtml()
+    public function testGetOutputFromHtml(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -459,7 +459,7 @@ public function testGetOutputFromHtml()
         $this->assertEquals('the output', $media->getOutputFromHtml('<html>foo</html>', ['foo' => 'bar']));
     }
 
-    public function testGetOutputFromHtmlWithHtmlArray()
+    public function testGetOutputFromHtmlWithHtmlArray(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -492,7 +492,7 @@ public function testGetOutputFromHtmlWithHtmlArray()
         $this->assertEquals('the output', $media->getOutputFromHtml(['<html>foo</html>'], ['foo' => 'bar']));
     }
 
-    public function testMergeOptions()
+    public function testMergeOptions(): void
     {
         $media = $this->getMockForAbstractClass(AbstractGenerator::class, [], '', false);
 
@@ -546,7 +546,7 @@ public function testMergeOptions()
     /**
      * @dataProvider dataForBuildCommand
      */
-    public function testBuildCommand($binary, $url, $path, $options, $expected)
+    public function testBuildCommand(string $binary, string $url, string $path, array $options, string $expected): void
     {
         $media = $this->getMockForAbstractClass(AbstractGenerator::class, [], '', false);
 
@@ -556,7 +556,7 @@ public function testBuildCommand($binary, $url, $path, $options, $expected)
         $this->assertEquals($expected, $r->invokeArgs($media, [$binary, $url, $path, $options]));
     }
 
-    private function getPHPExecutableFromPath()
+    private function getPHPExecutableFromPath(): ?string
     {
         if (isset($_SERVER['_'])) {
             return $_SERVER['_'];
@@ -566,6 +566,10 @@ private function getPHPExecutableFromPath()
             return PHP_BINARY;
         }
 
+        if (false === getenv('PATH')) {
+            return null;
+        }
+
         $paths = explode(PATH_SEPARATOR, getenv('PATH'));
         foreach ($paths as $path) {
             // we need this for XAMPP (Windows)
@@ -579,10 +583,10 @@ private function getPHPExecutableFromPath()
             }
         }
 
-        return false; // not found
+        return null; // not found
     }
 
-    public function dataForBuildCommand()
+    public function dataForBuildCommand(): array
     {
         $theBinary = $this->getPHPExecutableFromPath() . ' -v'; // i.e.: '/usr/bin/php -v'
 
@@ -649,7 +653,7 @@ public function dataForBuildCommand()
         ];
     }
 
-    public function testCheckOutput()
+    public function testCheckOutput(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -686,7 +690,7 @@ public function testCheckOutput()
         }
     }
 
-    public function testCheckOutputWhenTheFileDoesNotExist()
+    public function testCheckOutputWhenTheFileDoesNotExist(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -717,7 +721,7 @@ public function testCheckOutputWhenTheFileDoesNotExist()
         }
     }
 
-    public function testCheckOutputWhenTheFileIsEmpty()
+    public function testCheckOutputWhenTheFileIsEmpty(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -755,7 +759,7 @@ public function testCheckOutputWhenTheFileIsEmpty()
         }
     }
 
-    public function testCheckProcessStatus()
+    public function testCheckProcessStatus(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods(['configure'])
@@ -791,7 +795,7 @@ public function testCheckProcessStatus()
     /**
      * @dataProvider dataForIsAssociativeArray
      */
-    public function testIsAssociativeArray($array, $isAssociativeArray)
+    public function testIsAssociativeArray(array $array, bool $isAssociativeArray): void
     {
         $generator = $this->getMockForAbstractClass(AbstractGenerator::class, [], '', false);
 
@@ -803,7 +807,7 @@ public function testIsAssociativeArray($array, $isAssociativeArray)
     /**
      * @expectedException Knp\Snappy\Exception\FileAlreadyExistsException
      */
-    public function testItThrowsTheProperExceptionWhenFileExistsAndNotOverwritting()
+    public function testItThrowsTheProperExceptionWhenFileExistsAndNotOverwritting(): void
     {
         $media = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -831,7 +835,7 @@ public function testItThrowsTheProperExceptionWhenFileExistsAndNotOverwritting()
         $r->invokeArgs($media, ['', false]);
     }
 
-    public function dataForIsAssociativeArray()
+    public function dataForIsAssociativeArray(): array
     {
         return [
             [
@@ -869,7 +873,7 @@ public function dataForIsAssociativeArray()
         ];
     }
 
-    public function testCleanupEmptyTemporaryFiles()
+    public function testCleanupEmptyTemporaryFiles(): void
     {
         $generator = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -897,7 +901,7 @@ public function testCleanupEmptyTemporaryFiles()
         $remove->invoke($generator);
     }
 
-    public function testleanupTemporaryFiles()
+    public function testleanupTemporaryFiles(): void
     {
         $generator = $this->getMockBuilder(AbstractGenerator::class)
             ->setMethods([
@@ -925,10 +929,10 @@ public function testleanupTemporaryFiles()
         $remove->invoke($generator);
     }
 
-    public function testResetOptions()
+    public function testResetOptions(): void
     {
         $media = new class('/usr/local/bin/wkhtmltopdf') extends AbstractGenerator {
-            protected function configure()
+            protected function configure(): void
             {
                 $this->addOptions([
                     'optionA' => null,
diff --git a/tests/Knp/Snappy/ImageTest.php b/tests/Knp/Snappy/ImageTest.php
index 68b64bc0..6c2bb383 100644
--- a/tests/Knp/Snappy/ImageTest.php
+++ b/tests/Knp/Snappy/ImageTest.php
@@ -7,7 +7,7 @@
 
 class ImageTest extends TestCase
 {
-    public function testCreateInstance()
+    public function testCreateInstance(): void
     {
         $testObject = new Image();
         $this->assertInstanceOf(Image::class, $testObject);
diff --git a/tests/Knp/Snappy/PdfTest.php b/tests/Knp/Snappy/PdfTest.php
index 39c844be..bcfe3c4f 100644
--- a/tests/Knp/Snappy/PdfTest.php
+++ b/tests/Knp/Snappy/PdfTest.php
@@ -10,7 +10,7 @@ class PdfTest extends TestCase
 {
     const SHELL_ARG_QUOTE_REGEX = '(?:"|\')'; // escapeshellarg produces double quotes on Windows, single quotes otherwise
 
-    public function tearDown()
+    public function tearDown(): void
     {
         $directory = __DIR__ . '/i-dont-exist';
 
@@ -39,13 +39,13 @@ function ($filename) {
         }
     }
 
-    public function testCreateInstance()
+    public function testCreateInstance(): void
     {
         $testObject = new Pdf();
         $this->assertInstanceOf(Pdf::class, $testObject);
     }
 
-    public function testThatSomethingUsingTmpFolder()
+    public function testThatSomethingUsingTmpFolder(): void
     {
         $q = self::SHELL_ARG_QUOTE_REGEX;
         $testObject = new PdfSpy();
@@ -55,7 +55,7 @@ public function testThatSomethingUsingTmpFolder()
         $this->assertRegExp('/emptyBinary --lowquality --footer-html ' . $q . '.*' . $q . ' ' . $q . '.*' . $q . ' ' . $q . '.*' . $q . '/', $testObject->getLastCommand());
     }
 
-    public function testThatSomethingUsingNonexistentTmpFolder()
+    public function testThatSomethingUsingNonexistentTmpFolder(): void
     {
         $temporaryFolder = sys_get_temp_dir() . '/i-dont-exist';
 
@@ -67,7 +67,7 @@ public function testThatSomethingUsingNonexistentTmpFolder()
         $this->assertDirectoryExists($temporaryFolder);
     }
 
-    public function testRemovesLocalFilesOnError()
+    public function testRemovesLocalFilesOnError(): void
     {
         $pdf = new PdfSpy();
         $method = new \ReflectionMethod($pdf, 'createTemporaryFile');
@@ -82,14 +82,14 @@ public function testRemovesLocalFilesOnError()
     /**
      * @dataProvider dataOptions
      */
-    public function testOptions(array $options, $expectedRegex)
+    public function testOptions(array $options, string $expectedRegex): void
     {
         $testObject = new PdfSpy();
         $testObject->getOutputFromHtml('<html></html>', $options);
         $this->assertRegExp($expectedRegex, $testObject->getLastCommand());
     }
 
-    public function dataOptions()
+    public function dataOptions(): array
     {
         $q = self::SHELL_ARG_QUOTE_REGEX;
 
@@ -131,7 +131,7 @@ public function dataOptions()
         ];
     }
 
-    public function testRemovesLocalFilesOnDestruct()
+    public function testRemovesLocalFilesOnDestruct(): void
     {
         $pdf = new PdfSpy();
         $method = new \ReflectionMethod($pdf, 'createTemporaryFile');
@@ -146,6 +146,9 @@ public function testRemovesLocalFilesOnDestruct()
 
 class PdfSpy extends Pdf
 {
+    /**
+     * @var string
+     */
     private $lastCommand;
 
     public function __construct()
@@ -153,24 +156,24 @@ public function __construct()
         parent::__construct('emptyBinary');
     }
 
-    public function getLastCommand()
+    public function getLastCommand(): string
     {
         return $this->lastCommand;
     }
 
-    protected function executeCommand($command)
+    protected function executeCommand(string $command): array
     {
         $this->lastCommand = $command;
 
         return [0, 'output', 'errorOutput'];
     }
 
-    protected function checkOutput($output, $command)
+    protected function checkOutput(string $output, string $command): void
     {
         //let's say everything went right
     }
 
-    public function getOutput($input, array $options = [])
+    public function getOutput($input, array $options = []): string
     {
         $filename = $this->createTemporaryFile(null, $this->getDefaultExtension());
         $this->generate($input, $filename, $options, true);