Rename exception static method + rename test

Author: mbardelmeijer

src/CmsmsMessage.php

@@ -100,7 +100,7 @@ public function tariff($tariff)
     public function multipart($minimum, $maximum)
     {
         if (! is_int($minimum) || ! is_int($maximum) || $maximum > 8 || $minimum >= $maximum) {
-            throw InvalidMessage::invalidMessageParts($minimum, $maximum);
+            throw InvalidMessage::invalidMultipart($minimum, $maximum);
         }
 
         $this->minimumNumberOfMessageParts = $minimum;

src/Exceptions/InvalidMessage.php

@@ -38,8 +38,8 @@ public static function invalidTariff($tariff)
      * @param int $maximum
      * @return static
      */
-    public static function invalidMessageParts($minimum, $maximum)
+    public static function invalidMultipart($minimum, $maximum)
     {
-        return new static("The number of message parts on the CMSMS message may only contain a integer range from 0 to 8. Was given a minimum of '{$minimum}' and maximum of '{$maximum}'");
+        return new static("The number of message parts for sending a multipart message on the CMSMS message may only contain a integer range from 0 to 8. Was given a minimum of '{$minimum}' and maximum of '{$maximum}'");
     }
 }

tests/CmsmsMessageTest.php

@@ -139,7 +139,7 @@ public function it_cannot_set_a_float_to_multipart()
     }
 
     /** @test */
-    public function it_cannot_have_more_than_8_parts()
+    public function it_cannot_set_more_than_8_parts_to_multipart()
     {
         $this->setExpectedException(InvalidMessage::class);