Fix Expecting E_ERROR and E_USER_ERROR is deprecated

Expecting E_ERROR and E_USER_ERROR is deprecated and will no longer be
possible in PHPUnit 10.

helper_array_transpose() now throws a ClientException instead of calling
trigger_error() when detecting a non-bidimensional array.

Adapt HelperTest::testArrayTransposeInvalid() to handle the exception
instead of E_USER_ERROR.

core/helper_api.php

@@ -88,14 +88,18 @@ function helper_alternate_class( $p_index = null, $p_odd_class = 'row-1', $p_eve
  * becomes array('k1'=>array('a'=>1,'b'=>3),'k2'=>array('a'=>2,'b'=>4))
  *
  * @param array $p_array The array to transpose.
+ *
  * @return array|mixed transposed array or $p_array if not 2-dimensional array
+ * @throws ClientException
  */
 function helper_array_transpose( array $p_array ) {
 	$t_out = array();
 	foreach( $p_array as $t_key => $t_sub ) {
 		if( !is_array( $t_sub ) ) {
-			# This function can only handle bidimensional arrays
-			trigger_error( ERROR_GENERIC, ERROR );
+			throw new ClientException(
+				__FUNCTION__ . " can only handle bidimensional arrays",
+				ERROR_GENERIC
+			);
 		}
 
 		foreach( $t_sub as $t_subkey => $t_value ) {

tests/Mantis/HelperTest.php

@@ -24,6 +24,8 @@
  */
 
 # Includes
+use Mantis\Exceptions\ClientException;
+
 require_once 'MantisCoreBase.php';
 
 /**
@@ -41,6 +43,7 @@ class HelperTest extends MantisCoreBase {
 	 * @return void
 	 *
 	 * @dataProvider providerArrayTransposeValid
+	 * @throws ClientException
 	 */
 	public function testArrayTransposeValid( $p_in, $p_out ) {
 		$this->assertEquals( $p_out, helper_array_transpose( $p_in ) );
@@ -55,9 +58,9 @@ public function testArrayTransposeValid( $p_in, $p_out ) {
 	 * @dataProvider providerArrayTransposeInvalid
 	 */
 	public function testArrayTransposeInvalid( $p_in ) {
-		$this->expectException(PHPUnit\Framework\Error\Error::class);
-		$this->expectExceptionCode(E_USER_ERROR);
-		$this->expectExceptionMessage((string)ERROR_GENERIC);
+		$this->expectException( ClientException::class );
+		$this->expectExceptionMessage( 'helper_array_transpose can only handle bidimensional arrays' );
+
 		helper_array_transpose( $p_in );
 	}