unittest for fixed string alteration added

tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php

@@ -755,4 +755,32 @@ abstract class AbstractPostgreSqlPlatformTestCase extends AbstractPlatformTestCa
     {
         return 'INDEX "select" (foo)';
     }
+
+    /**
+     * @todo add issue ticket number as phpunit group
+     */
+    public function testAlterStringToFixedString()
+    {
+
+        $table = new Table('mytable');
+        $table->addColumn('name', 'string', array('length' => 2));
+
+        $tableDiff = new TableDiff('mytable');
+        $tableDiff->fromTable = $table;
+
+        $tableDiff->changedColumns['dloo1'] = new \Doctrine\DBAL\Schema\ColumnDiff(
+            'name', new \Doctrine\DBAL\Schema\Column(
+                'name', \Doctrine\DBAL\Types\Type::getType('string'), array('fixed' => true, 'length' => 2)
+            ),
+            array('fixed')
+        );
+
+        $sql = $this->_platform->getAlterTableSQL($tableDiff);
+
+        $expectedSql = array(
+            'ALTER TABLE mytable ALTER name TYPE CHAR(2)',
+        );
+
+        $this->assertEquals($expectedSql, $sql);
+    }
 }