Added a test to check if changing a comment would produce the right ALTER TABLE script.

Author: Carlos Cima

tests/DifferTest.php

@@ -74,6 +74,19 @@ public function testIsDiffingChangedTable()
         $differ->diffChangedTable($changedTable);
     }
 
+    public function testIsDiffingChangedComment()
+    {
+        $parser = new Parser();
+
+        $fromDatabase = $parser->parseDatabase($this->getDatabaseFixture('comment_change1.sql'));
+        $toDatabase = $parser->parseDatabase($this->getDatabaseFixture('comment_change2.sql'));
+
+        $differ = new Differ();
+        $databaseDiff = $differ->diffDatabases($fromDatabase, $toDatabase);
+
+        $this->assertContains('CHANGE COLUMN `field1` `field1` varchar(50) NOT NULL COMMENT \'New Comment\' FIRST;', $differ->generateMigrationScript($databaseDiff));
+    }
+
     public function testIsGeneratingMigrationScript()
     {
         $parser = new Parser();

tests/fixtures/comment_change1.sql

@@ -0,0 +1,3 @@
+CREATE TABLE `comments` (
+  `field1` varchar(50) NOT NULL COMMENT 'Old Comment',
+) ENGINE=InnoDB;

tests/fixtures/comment_change2.sql

@@ -0,0 +1,3 @@
+CREATE TABLE `comments` (
+  `field1` varchar(50) NOT NULL COMMENT 'New Comment',
+) ENGINE=InnoDB;