BigRational now implements Serializable

This allows for a more compact serialized representation.

src/BigDecimal.php

@@ -753,8 +753,6 @@ class BigDecimal implements \Serializable
     /**
      * This method is required by interface Serializable and MUST NOT be accessed directly.
      *
-     * Accessing this method directly would bypass consistency checks and break immutability.
-     *
      * @internal
      *
      * @param string $value

src/BigRational.php

@@ -7,7 +7,7 @@ namespace Brick\Math;
  *
  * This class is immutable.
  */
-class BigRational
+class BigRational implements \Serializable
 {
     /**
      * The numerator.
@@ -387,4 +387,37 @@ class BigRational
 
         return $this->numerator . '/' . $this->denominator;
     }
+
+    /**
+     * This method is required by interface Serializable and SHOULD NOT be accessed directly.
+     *
+     * @internal
+     *
+     * @return string
+     */
+    public function serialize()
+    {
+        return $this->numerator . '/' . $this->denominator;
+    }
+
+    /**
+     * This method is required by interface Serializable and MUST NOT be accessed directly.
+     *
+     * @internal
+     *
+     * @param string $value
+     *
+     * @return void
+     */
+    public function unserialize($value)
+    {
+        if ($this->numerator !== null || $this->denominator !== null) {
+            throw new \LogicException('unserialize() is an internal function, it must not be called directly.');
+        }
+
+        list ($numerator, $denominator) = explode('/', $value);
+
+        $this->numerator   = BigInteger::of($numerator);
+        $this->denominator = BigInteger::of($denominator);
+    }
 }

tests/BigRationalTest.php

@@ -550,4 +550,22 @@ class BigRationalTest extends AbstractTestCase
             ['34327948737247817984738927598572389', '-1', '-34327948737247817984738927598572389'],
         ];
     }
+
+    public function testSerialize()
+    {
+        $numerator   = '-1234567890987654321012345678909876543210123456789';
+        $denominator = '347827348278374374263874681238374983729873401984091287439827467286';
+
+        $rational = BigRational::of($numerator, $denominator);
+
+        $this->assertBigRationalEquals($numerator, $denominator, unserialize(serialize($rational)));
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testDirectCallToUnserialize()
+    {
+        BigRational::of(1, 2)->unserialize('123/456');
+    }
 }