add __toString function on attributes fix #13

src/Attribute/AttributeInterface.php

@@ -4,4 +4,8 @@
 
 interface AttributeInterface
 {
+    /**
+     * @return string
+     */
+    public function __toString();
 }

src/Attribute/Cover.php

@@ -24,4 +24,12 @@ public function getBinaryCover()
     {
         return $this->binaryCover;
     }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        return $this->binaryCover;
+    }
 }

src/Attribute/Duration.php

@@ -25,4 +25,12 @@ public function getMilliseconds()
     {
         return $this->milliseconds;
     }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        return (string) $this->milliseconds;
+    }
 }

src/Attribute/Mode.php

@@ -40,4 +40,12 @@ public function getShortName()
     {
         return $this->shortName;
     }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        return $this->shortName;
+    }
 }

src/Attribute/Rate.php

@@ -41,4 +41,12 @@ public function getTextValue()
     {
         return $this->textValue;
     }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        return $this->textValue;
+    }
 }

src/Attribute/Size.php

@@ -26,4 +26,12 @@ public function getBit()
     {
         return $this->bit;
     }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        return (string) $this->bit;
+    }
 }

test/Attribute/AttributeTest.php

@@ -14,31 +14,36 @@ public function testCover()
     {
         $cover = new Cover('binary_string');
         $this->assertEquals('binary_string', $cover->getBinaryCover());
+        $this->assertSame('binary_string', (string)$cover);
     }
 
     public function testDuration()
     {
         $duration = new Duration(1000);
         $this->assertEquals(1000, $duration->getMilliseconds());
+        $this->assertSame('1000', (string)$duration);
     }
 
     public function testMode()
     {
         $mode = new Mode('short', 'full');
         $this->assertEquals('short', $mode->getShortName());
         $this->assertEquals('full', $mode->getFullName());
+        $this->assertSame('short', (string)$mode);
     }
 
     public function testRate()
     {
         $rate = new Rate(15555, '15.55 Mo');
         $this->assertEquals(15555, $rate->getAbsoluteValue());
         $this->assertEquals('15.55 Mo', $rate->getTextValue());
+        $this->assertSame('15.55 Mo', (string)$rate);
     }
 
     public function testSize()
     {
         $size = new Size(42);
         $this->assertEquals(42, $size->getBit());
+        $this->assertSame('42', (string)$size);
     }
 }