install: check file/directory permissions for Shaarli resources

Relates to #40
Relates to #372

Additions:
 - FileUtils: IOException
 - ApplicationUtils:
   - check if Shaarli resources are accessible with sufficient permissions
   - basic test coverage
 - index.php:
   - check access permissions and redirect to an error page if needed:
     - before running the first installation

Modifications:
 - LinkDB:
   - factorize datastore write code
   - check if the datastore
     (exists AND is writeable) OR (doesn't exist AND its parent dir is writable)
   - raise an IOException if needed

Signed-off-by: VirtualTam <virtualtam@flibidi.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/tests/LinkDBTest.php b/tests/LinkDBTest.php
index 451f1d6f..8929713d 100644
--- a/tests/LinkDBTest.php
+++ b/tests/LinkDBTest.php
@@ -4,6 +4,7 @@
  */
 
 require_once 'application/Cache.php';
+require_once 'application/FileUtils.php';
 require_once 'application/LinkDB.php';
 require_once 'application/Utils.php';
 require_once 'tests/utils/ReferenceLinkDB.php';
@@ -87,8 +88,8 @@ class LinkDBTest extends PHPUnit_Framework_TestCase
     /**
      * Attempt to instantiate a LinkDB whereas the datastore is not writable
      *
-     * @expectedException              PHPUnit_Framework_Error_Warning
-     * @expectedExceptionMessageRegExp /failed to open stream: No such file or directory/
+     * @expectedException              IOException
+     * @expectedExceptionMessageRegExp /Error accessing null/
      */
     public function testConstructDatastoreNotWriteable()
     {