diff --git a/test/corpora/default/bar/baz/05:2, b/test/corpora/default/bar/baz/05:2,
index 75b05fa4..ce174b52 100644
--- a/test/corpora/default/bar/baz/05:2,
+++ b/test/corpora/default/bar/baz/05:2,
@@ -63,7 +63,7 @@ and <a href=3D"http://mail-index.netbsd.org/pkgsrc-bugs/2006/06/07/msg01680=
 
 --0016e687869333b14e0478963d33--
 --0016e687869333b1570478963d35
-Content-Type: application/octet-stream; 
+Content-Type: text/x-diff;
 	name="0001-Deal-with-situation-where-sysconf-_SC_GETPW_R_SIZE_M.patch"
 Content-Disposition: attachment; 
 	filename="0001-Deal-with-situation-where-sysconf-_SC_GETPW_R_SIZE_M.patch"
diff --git a/test/emacs-show.expected-output/notmuch-show-multipart-alternative b/test/emacs-show.expected-output/notmuch-show-multipart-alternative
index e44926bc..e2951d2b 100644
--- a/test/emacs-show.expected-output/notmuch-show-multipart-alternative
+++ b/test/emacs-show.expected-output/notmuch-show-multipart-alternative
@@ -24,7 +24,7 @@ http://mail-index.netbsd.org/pkgsrc-bugs/2006/06/07/msg016808.htmlspecifically
 uses 64 as the
 buffer size.
 [ text/html (hidden) ]
-[ 0001-Deal-with-situation-where-sysconf-_SC_GETPW_R_SIZE_M.patch: application/octet-stream (as text/x-diff) ]
+[ 0001-Deal-with-situation-where-sysconf-_SC_GETPW_R_SIZE_M.patch: text/x-diff ]
 From e3bc4bbd7b9d0d086816ab5f8f2d6ffea1dd3ea4 Mon Sep 17 00:00:00 2001
 From: Alexander Botero-Lowry <alex.boterolowry@gmail.com>
 Date: Tue, 17 Nov 2009 11:30:39 -0800
diff --git a/test/emacs.expected-output/raw-message-cf0c4d-52ad0a b/test/emacs.expected-output/raw-message-cf0c4d-52ad0a
index 75b05fa4..ce174b52 100644
--- a/test/emacs.expected-output/raw-message-cf0c4d-52ad0a
+++ b/test/emacs.expected-output/raw-message-cf0c4d-52ad0a
@@ -63,7 +63,7 @@ and <a href=3D"http://mail-index.netbsd.org/pkgsrc-bugs/2006/06/07/msg01680=
 
 --0016e687869333b14e0478963d33--
 --0016e687869333b1570478963d35
-Content-Type: application/octet-stream; 
+Content-Type: text/x-diff;
 	name="0001-Deal-with-situation-where-sysconf-_SC_GETPW_R_SIZE_M.patch"
 Content-Disposition: attachment; 
 	filename="0001-Deal-with-situation-where-sysconf-_SC_GETPW_R_SIZE_M.patch"