diff --git a/nbdkit.spec b/nbdkit.spec
index f8965c8..d18e9c9 100644
--- a/nbdkit.spec
+++ b/nbdkit.spec
@@ -39,8 +39,6 @@ BuildRequires:  autoconf, automake, libtool
 %endif
 BuildRequires:  /usr/bin/pod2man
 BuildRequires:  gnutls-devel
-# Only for running the test suite:
-BuildRequires:  /usr/bin/certtool
 BuildRequires:  libselinux-devel
 %if 0%{?have_libguestfs}
 BuildRequires:  libguestfs-devel
@@ -62,6 +60,10 @@ BuildRequires:  ocaml >= 4.02.2
 %endif
 BuildRequires:  ruby-devel
 
+# Only for running the test suite:
+BuildRequires:  /usr/bin/certtool
+BuildRequires:  /usr/bin/socat
+BuildRequires:  /usr/sbin/ss
 
 %description
 NBD is a protocol for accessing block devices (hard disks and