diff --git a/src/Testing/CodeHacking/CodeHacker.php b/src/Testing/CodeHacking/CodeHacker.php
index 967c5cdd8a9..9c3696416e6 100644
--- a/src/Testing/CodeHacking/CodeHacker.php
+++ b/src/Testing/CodeHacking/CodeHacker.php
@@ -31,9 +31,10 @@ use \ReflectionException;
  *
  * For using with PHPUnit, see CodeHackerTestHook.
  */
-class CodeHacker {
+final class CodeHacker {
 
-	const PROTOCOL = 'file';
+	const PROTOCOL                     = 'file';
+	const HACK_CALLBACK_ARGUMENT_COUNT = 2;
 
 	/**
 	 * Value of "context" parameter to be passed to the native PHP filesystem related functions.
@@ -132,11 +133,11 @@ class CodeHacker {
 	 */
 	public static function add_hack( $hack, $persistent = false ) {
 		if ( ! is_callable( $hack ) && ! is_object( $hack ) ) {
-			throw new \Exception( "Hacks must be either functions, or objects having a 'process(\$text, \$path)' method." );
+			throw new \Exception( "CodeHacker::addhack: Hacks must be either functions, or objects having a 'process(\$text, \$path)' method." );
 		}
 
 		if ( ! self::is_valid_hack_callback( $hack ) && ! self::is_valid_hack_object( $hack ) ) {
-			throw new \Exception( "CodeHacker::addhack: hacks must be either a function with a 'hack(\$code,\$path)' signature, or an object containing a public method 'hack' with that signature. " );
+			throw new \Exception( "CodeHacker::addhack: Hacks must be either a function with a 'hack(\$code,\$path)' signature, or an object containing a public method 'hack' with that signature. " );
 		}
 
 		if ( $persistent ) {
@@ -154,7 +155,7 @@ class CodeHacker {
 	 * @throws ReflectionException Error when instantiating ReflectionFunction.
 	 */
 	private static function is_valid_hack_callback( $callback ) {
-		return is_callable( $callback ) && 2 === ( new ReflectionFunction( $callback ) )->getNumberOfRequiredParameters();
+		return is_callable( $callback ) && HACK_CALLBACK_ARGUMENT_COUNT === ( new ReflectionFunction( $callback ) )->getNumberOfRequiredParameters();
 	}
 
 	/**
@@ -162,7 +163,7 @@ class CodeHacker {
 	 *
 	 * @param mixed $callback Argument to check.
 	 *
-	 * @return boolt rue if the argument is a valid hack object, false otherwise.
+	 * @return bool rue if the argument is a valid hack object, false otherwise.
 	 */
 	private static function is_valid_hack_object( $callback ) {
 		if ( ! is_object( $callback ) ) {
diff --git a/src/Testing/CodeHacking/CodeHackerTestHook.php b/src/Testing/CodeHacking/CodeHackerTestHook.php
index 0d96a2515ba..f5c84696064 100644
--- a/src/Testing/CodeHacking/CodeHackerTestHook.php
+++ b/src/Testing/CodeHacking/CodeHackerTestHook.php
@@ -5,8 +5,6 @@
  * @package WooCommerce/Testing
  */
 
-// phpcs:disable Squiz.Commenting.FunctionComment.Missing, PHPCompatibility.FunctionDeclarations
-
 namespace Automattic\WooCommerce\Testing\CodeHacking;
 
 use PHPUnit\Runner\BeforeTestHook;
@@ -64,12 +62,27 @@ use Exception;
  */
 final class CodeHackerTestHook implements BeforeTestHook, AfterTestHook {
 
+	// phpcs:disable PHPCompatibility.FunctionDeclarations.NewReturnTypeDeclarations.voidFound
+
+	/**
+	 * Runs after each test.
+	 *
+	 * @param string $test "TestClass::TestMethod".
+	 * @param float  $time The time it took the test to run, in seconds.
+	 */
 	public function executeAfterTest( string $test, float $time ): void {
 		if ( ! CodeHacker::has_persistent_hacks() ) {
 			CodeHacker::disable();
 		}
 	}
 
+	/**
+	 * Runs before each test.
+	 *
+	 * @param string $test "TestClass::TestMethod".
+	 *
+	 * @throws \ReflectionException Thrown by execute_before_methods.
+	 */
 	public function executeBeforeTest( string $test ): void {
 		/**
 		 * Possible formats of $test:
@@ -79,7 +92,7 @@ final class CodeHackerTestHook implements BeforeTestHook, AfterTestHook {
 		 */
 		$parts = explode( '::', $test );
 		if ( count( $parts ) < 2 ) {
-			return;
+			return;  // "Warning" was supplied as argument
 		}
 		$class_name  = $parts[0];
 		$method_name = explode( ' ', $parts[1] )[0];
@@ -95,6 +108,8 @@ final class CodeHackerTestHook implements BeforeTestHook, AfterTestHook {
 		}
 	}
 
+	// phpcs:enable PHPCompatibility.FunctionDeclarations.NewReturnTypeDeclarations.voidFound
+
 	/**
 	 * Apply hacks defined in @hack annotations.
 	 *
@@ -164,4 +179,3 @@ final class CodeHackerTestHook implements BeforeTestHook, AfterTestHook {
 	}
 }
 
-// phpcs:enable Squiz.Commenting.FunctionComment.Missing, PHPCompatibility.FunctionDeclarations
diff --git a/src/Testing/CodeHacking/Hacks/CodeHack.php b/src/Testing/CodeHacking/Hacks/CodeHack.php
index 47e11f2a058..392845ace15 100644
--- a/src/Testing/CodeHacking/Hacks/CodeHack.php
+++ b/src/Testing/CodeHacking/Hacks/CodeHack.php
@@ -29,10 +29,14 @@ abstract class CodeHack {
 	 *
 	 * @param string $code PHP code to tokenize.
 	 * @return array Tokenized code.
+	 * @throws \Exception PHP version is less than 7.0.
 	 */
 	protected function tokenize( $code ) {
-		//phpcs:ignore PHPCompatibility.FunctionUse.NewFunctionParameters, PHPCompatibility.Constants.NewConstants
-		return PHP_VERSION_ID >= 70000 ? token_get_all( $code, TOKEN_PARSE ) : token_get_all( $code );
+		if ( PHP_VERSION_ID < 70000 ) {
+			throw new \Exception( 'The code hacker can be used in PHP 7.0+ only.' );
+		}
+
+		return token_get_all( $code, TOKEN_PARSE );
 	}
 
 	/**