these tests don't work on little-end systems

tests/src/Codec/GuidStringCodecTest.php

@@ -51,7 +51,7 @@ class GuidStringCodecTest extends TestCase
 
     public function testEncodeReturnsFormattedString()
     {
-        $this->skipIfLittleEndianHost();
+        $this->skipIfBigEndianHost();
         $this->uuid->method('getFieldsHex')
             ->willReturn($this->fields);
         $codec = new GuidStringCodec($this->builder);
@@ -80,7 +80,7 @@ class GuidStringCodecTest extends TestCase
 
     public function testDecodeUsesBuilderOnFields()
     {
-        $this->skipIfLittleEndianHost();
+        $this->skipIfBigEndianHost();
         $string = 'uuid:78563412-3412-cdab-abef-1234abcd4321';
         $this->builder->expects($this->once())
             ->method('build')