diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index 61972c3876..6b6a9b1f9f 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -1910,7 +1910,7 @@ function validate_jabber($jid)
 */
 function phpbb_validate_hex_colour($colour, $optional = false)
 {
-	if (empty($colour))
+	if ($colour === '')
 	{
 		return (($optional) ? false : 'WRONG_DATA');
 	}
diff --git a/tests/functional/common_groups_test.php b/tests/functional/common_groups_test.php
index 02a538d46e..7ccd78421e 100644
--- a/tests/functional/common_groups_test.php
+++ b/tests/functional/common_groups_test.php
@@ -17,21 +17,11 @@ abstract class phpbb_functional_common_groups_test extends phpbb_functional_test
 	public function groups_manage_test_data()
 	{
 		return array(
-			array('#AA0000', 'WRONG_DATA_COLOUR'),
-			array('AA0000', 'GROUP_UPDATED'),
-			array('AA0000v', 'WRONG_DATA_COLOUR'),
-			array('AA00000', 'WRONG_DATA_COLOUR'),
-			array('vAA0000', 'WRONG_DATA_COLOUR'),
-			array('AAG000','WRONG_DATA_COLOUR'),
-			array('a00', 'GROUP_UPDATED'),
-			array('ag0', 'WRONG_DATA_COLOUR'),
-			array('#aa0', 'WRONG_DATA_COLOUR'),
-			array('AA0000 ', 'GROUP_UPDATED'),
-			array('AA0000 abf', 'WRONG_DATA_COLOUR'),
-			array('AA0000 AA0000', 'WRONG_DATA_COLOUR'),
 			array('', 'GROUP_UPDATED'),
-			array('000', 'GROUP_UPDATED'),
-			array('000000', 'GROUP_UPDATED'),
+			array('aa0000', 'GROUP_UPDATED'),
+
+			array('AAG000','WRONG_DATA_COLOUR'),
+			array('#AA0000', 'WRONG_DATA_COLOUR'),
 		);
 	}
 
diff --git a/tests/functions/validate_hex_colour_test.php b/tests/functions/validate_hex_colour_test.php
new file mode 100644
index 0000000000..812ebe5eeb
--- /dev/null
+++ b/tests/functions/validate_hex_colour_test.php
@@ -0,0 +1,121 @@
+<?php
+/**
+*
+* @package testing
+* @copyright (c) 2013 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+require_once dirname(__FILE__) . '/../../phpBB/includes/functions_user.php';
+
+class phpbb_functions_validate_hex_colour_test extends phpbb_test_case
+{
+	public function positive_match_data()
+	{
+		return array(
+			array('a00'),
+			array('AFF'),
+			array('AA0000'),
+			array('aa00FF'),
+			array('000'),
+			array('000000'),
+		);
+	}
+
+	public function negative_match_data()
+	{
+		return array(
+			// Invalid prefix
+			array('#aa0'),
+			array('#AA0000'),
+			array('vAA0000'),
+
+			// Invalid suffix
+			array('AA0000v'),
+
+			// Correct length, but out of hex range
+			array('ag0'),
+			array('AAG000'),
+
+			// Too long
+			array('AA00000'),
+			array('AA0000 '),
+			array('AA0000 abf'),
+			array('AA0000 AA0000'),
+
+			// empty()
+			array('0'),
+		);
+	}
+
+	public function optional_only_data()
+	{
+		return array(
+			// The empty colour, i.e. "no colour".
+			array(''),
+		);
+	}
+
+	public function strict_negative_match_data()
+	{
+		return array_merge(
+			$this->negative_match_data(),
+			$this->optional_only_data()
+		);
+	}
+
+	public function nonstrict_positive_match_data()
+	{
+		return array_merge(
+			$this->positive_match_data(),
+			$this->optional_only_data()
+		);
+	}
+
+	/**
+	* @dataProvider positive_match_data
+	*/
+	public function test_strict_positive_match($input)
+	{
+		$this->assertFalse(
+			phpbb_validate_hex_colour($input, false),
+			"Failed asserting that $input passes as a valid hex colour."
+		);
+	}
+
+	/**
+	* @dataProvider strict_negative_match_data
+	*/
+	public function test_strict_negative_match($input)
+	{
+		$this->assertSame(
+			'WRONG_DATA',
+			phpbb_validate_hex_colour($input, false),
+			"Failed asserting that $input does not pass as a valid hex colour."
+		);
+	}
+
+	/**
+	* @dataProvider nonstrict_positive_match_data
+	*/
+	public function test_nonstrict_positive_match($input)
+	{
+		$this->assertFalse(
+			phpbb_validate_hex_colour($input, true),
+			"Failed asserting that $input passes as a valid or optional hex colour."
+		);
+	}
+
+	/**
+	* @dataProvider negative_match_data
+	*/
+	public function test_nonstrict_negative_match($input)
+	{
+		$this->assertSame(
+			'WRONG_DATA',
+			phpbb_validate_hex_colour($input, true),
+			"Failed asserting that $input does not pass as a valid or optional hex colour."
+		);
+	}
+}