added helper function genDiff to differ

Author: Alexsey-VR

bin/gendiff

@@ -16,7 +16,7 @@ use Differ\Factories\Formatters;
 use Differ\Exceptions\DifferException;
 
 $differ = new Differ(
-    $commandFactory = new CommandFactory(
+    new CommandFactory(
         new \Docopt(),
         new FileReader(),
         new Formatters()

src/Differ.php

@@ -12,6 +12,7 @@
 use Differ\Readers\FileReader;
 use Differ\Factories\Formatters;
 use Differ\Exceptions\DifferException;
+use Differ\Parsers\DocoptDouble;
 
 class Differ
 {
@@ -130,3 +131,23 @@ public function genDiff(
                                         ->getFilesDiffs();
     }
 }
+
+function genDiff(
+    string $pathToFile1,
+    string $pathToFile2,
+    string $format = 'stylish'
+): string {
+    $differ = new Differ(
+        new CommandFactory(
+            new DocoptDouble(),
+            new FileReader(),
+            new Formatters()
+        )
+    );
+
+    return $differ->genDiff(
+        $pathToFile1,
+        $pathToFile2,
+        $format
+    );
+}

tests/Unit/GendiffConsoleTest.php

@@ -86,7 +86,7 @@ public function testAPIDiffer($formatter, $filePath)
     {
         $commandLineParser = is_null($formatter) ? new DocoptDouble() : new DocoptDouble($formatter);
         $differ = new Differ(
-            $commandFactory = new CommandFactory(
+            new CommandFactory(
                 $commandLineParser,
                 new FileReader(),
                 new Formatters()