diff --git a/src/Header/GenericHeader.php b/src/Header/GenericHeader.php
index e0b73936..6a2aa826 100644
--- a/src/Header/GenericHeader.php
+++ b/src/Header/GenericHeader.php
@@ -117,7 +117,7 @@ public function setFieldValue($fieldValue)
 
     public function getFieldValue($format = HeaderInterface::FORMAT_RAW)
     {
-        if (HeaderInterface::FORMAT_ENCODED) {
+        if (HeaderInterface::FORMAT_ENCODED === $format) {
             return HeaderWrap::wrap($this->fieldValue, $this);
         }
 
diff --git a/src/Header/Subject.php b/src/Header/Subject.php
index 73747363..f0386570 100644
--- a/src/Header/Subject.php
+++ b/src/Header/Subject.php
@@ -55,7 +55,7 @@ public function getFieldName()
 
     public function getFieldValue($format = HeaderInterface::FORMAT_RAW)
     {
-        if (HeaderInterface::FORMAT_ENCODED) {
+        if (HeaderInterface::FORMAT_ENCODED === $format) {
             return HeaderWrap::wrap($this->subject, $this);
         }
 
diff --git a/test/Header/SubjectTest.php b/test/Header/SubjectTest.php
index a2aa16f7..8fd618d6 100644
--- a/test/Header/SubjectTest.php
+++ b/test/Header/SubjectTest.php
@@ -27,7 +27,7 @@ public function testHeaderFolding()
         $subject->setSubject($string);
 
         $expected = wordwrap($string, 78, "\r\n ");
-        $test     = $subject->getFieldValue();
+        $test     = $subject->getFieldValue(Header\HeaderInterface::FORMAT_ENCODED);
         $this->assertEquals($expected, $test);
     }
 }