Add test with zero string value

Author: michalbundyra

test/HeaderTest.php

@@ -128,6 +128,20 @@ public function testSetIntValueViaConstructor($class, $name)
         self::assertSame($name . ': 100', $header->toString());
     }
 
+    /**
+     * @dataProvider header
+     *
+     * @param string $class
+     * @param string $name
+     */
+    public function testSetZeroStringValueViaConstructor($class, $name)
+    {
+        $header = new $class('0');
+
+        self::assertSame('0', $header->getFieldValue());
+        self::assertSame($name . ': 0', $header->toString());
+    }
+
     /**
      * @dataProvider header
      *