Simplify to just checking if file or not

Update tests for simplified exception

Author: martijnengler

src/Comment.php

@@ -204,12 +204,8 @@ public static function parse(string $json, bool $assoc = false, int $depth = 512
 
     public static function parseFromFile(string $file, bool $assoc = false, int $depth = 512, int $options = 0)
     {
-        if (!file_exists($file)) {
-            throw new \RuntimeException(sprintf('File %s does not exist', $file));
-        }
-
         if (!is_file($file)) {
-            throw new \RuntimeException(sprintf('%s is not a file', $file));
+            throw new \RuntimeException($file . ' does not exist or is not a file');
         }
 
         $json = \file_get_contents($file);

tests/CommentTest.php

@@ -70,16 +70,18 @@ public function testParseFromFile()
 
     public function testParseFromFileThrowsNotExists()
     {
+        $file = 'does-not-exist.json';
+
         $this->expectException(\RuntimeException::class);
-        $this->expectExceptionMessage('File does-not-exist.json does not exist');
+        $this->expectExceptionMessage($file . ' does not exist or is not a file');
 
-        Comment::parseFromFile('does-not-exist.json', true);
+        Comment::parseFromFile($file, true);
     }
 
     public function testParseFromFileThrowsNotFile()
     {
         $this->expectException(\RuntimeException::class);
-        $this->expectExceptionMessage(__DIR__ . ' is not a file');
+        $this->expectExceptionMessage(__DIR__ . ' does not exist or is not a file');
 
         Comment::parseFromFile(__DIR__, true);
     }