diff --git a/.gitignore b/.gitignore
index 0fff656..3b247d6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@
 /avocado-48.0.tar.gz
 /avocado-49.0.tar.gz
 /avocado-50.0.tar.gz
+/avocado-51.0.tar.gz
diff --git a/python-avocado.spec b/python-avocado.spec
index 6c660c0..df08191 100644
--- a/python-avocado.spec
+++ b/python-avocado.spec
@@ -10,10 +10,10 @@
     %global gittar		%{srcname}-%{version}.tar.gz
 %else
     %if ! 0%{?commit:1}
-        %global commit		6e726259cb8da6b97af64839a2af3410d1b6f620
+        %global commit		a7275046bf1cf6fee52f7dbdf4bf5b97f6f2b3da
     %endif
     %if ! 0%{?commit_date:1}
-        %global commit_date	20170516
+        %global commit_date	20170612
     %endif
     %global shortcommit	%(c=%{commit};echo ${c:0:7})
     %global gitrel		.%{commit_date}git%{shortcommit}
@@ -24,10 +24,15 @@
 # the functional tests are time and resource sensitive and can
 # cause race conditions and random build failures. They are
 # enabled by default.
+# However, selftests need to be disabled when libvirt is not available.
 %global with_tests 1
+%if 0%{?rhel}
+    # libvirt is not available for all RHEL builder architectures
+    %global with_tests 0
+%endif
 
 Name: python-%{srcname}
-Version: 50.0
+Version: 51.0
 Release: 1%{?gitrel}%{?dist}
 Summary: Framework with tools and libraries for Automated Testing
 Group: Development/Tools
@@ -55,9 +60,14 @@ BuildRequires: python-lxml
 BuildRequires: python2-mock
 BuildRequires: python-resultsdb_api
 
-%if %{with_tests}
+%if 0%{?with_tests}
 BuildRequires: libvirt-python
 BuildRequires: perl(TAP::Parser)
+%if 0%{?rhel}
+BuildRequires: python-yaml
+%else
+BuildRequires: python2-yaml
+%endif
 %endif
 
 %if 0%{?rhel}
@@ -66,14 +76,12 @@ BuildRequires: python-requests
 BuildRequires: python-setuptools
 BuildRequires: python-sphinx
 BuildRequires: python-stevedore
-BuildRequires: python-yaml
 %else
 BuildRequires: python2-psutil
 BuildRequires: python2-requests
 BuildRequires: python2-setuptools
 BuildRequires: python2-sphinx
 BuildRequires: python2-stevedore
-BuildRequires: python2-yaml
 %endif
 
 %if 0%{?el6}
@@ -86,9 +94,15 @@ BuildRequires: python-unittest2
 BuildRequires: procps-ng
 %endif
 
+# For some strange reason, fabric on Fedora 24 does not require the
+# python-crypto package, but the fabric code always imports it.  Newer
+# fabric versions, such from Fedora 25 do conditional imports (try:
+# from Crypto import Random; except: Random = None) and thus do not
+# need this requirement.
 %if 0%{?fedora} == 24
 BuildRequires: python-crypto
 %endif
+
 %if 0%{?fedora} >= 25
 BuildRequires: kmod
 %endif
@@ -108,7 +122,6 @@ License: GPLv2 and MIT
 Requires: fabric
 Requires: gdb
 Requires: gdb-gdbserver
-Requires: libvirt-python
 Requires: pyliblzma
 Requires: pystache
 Requires: python2
@@ -116,11 +129,9 @@ Requires: python2
 %if 0%{?rhel}
 Requires: python-requests
 Requires: python-stevedore
-Requires: python-yaml
 %else
 Requires: python2-requests
 Requires: python2-stevedore
-Requires: python2-yaml
 %endif
 
 %if 0%{?el6}
@@ -202,6 +213,21 @@ Allows Avocado to send job results directly to a ResultsDB
 server.
 
 
+%package -n python2-%{srcname}-plugins-varianter-yaml-to-mux
+Summary: Avocado plugin to generate variants out of yaml files
+%{?python_provide:%python_provide python2-%{srcname}-plugins-resultsdb}
+Requires: python2-%{srcname} == %{version}-%{release}
+%if 0%{?rhel}
+Requires: python-yaml
+%else
+Requires: python2-yaml
+%endif
+
+%description -n python2-%{srcname}-plugins-varianter-yaml-to-mux
+Can be used to produce multiple test variants with test parameters
+defined in a yaml file(s).
+
+
 %package -n python-%{srcname}-examples
 Summary: Avocado Test Framework Example Tests
 License: GPLv2
@@ -231,16 +257,19 @@ pushd optional_plugins/html
     %{__python2} setup.py build
 popd
 pushd optional_plugins/runner_remote
-    %{__python} setup.py build
+    %{__python2} setup.py build
 popd
 pushd optional_plugins/runner_vm
-    %{__python} setup.py build
+    %{__python2} setup.py build
 popd
 pushd optional_plugins/runner_docker
-    %{__python} setup.py build
+    %{__python2} setup.py build
 popd
 pushd optional_plugins/resultsdb
-    %{__python} setup.py build
+    %{__python2} setup.py build
+popd
+pushd optional_plugins/varianter_yaml_to_mux
+    %{__python2} setup.py build
 popd
 %{__make} man
 
@@ -261,6 +290,9 @@ popd
 pushd optional_plugins/resultsdb
     %{__python2} setup.py install --root %{buildroot} --skip-build
 popd
+pushd optional_plugins/varianter_yaml_to_mux
+    %{__python2} setup.py install --root %{buildroot} --skip-build
+popd
 %{__mkdir_p} %{buildroot}%{_mandir}/man1
 %{__install} -m 0644 man/avocado.1 %{buildroot}%{_mandir}/man1/avocado.1
 %{__install} -m 0644 man/avocado-rest-client.1 %{buildroot}%{_mandir}/man1/avocado-rest-client.1
@@ -273,7 +305,7 @@ find %{buildroot}%{_docdir}/avocado -type f -name '*.py' -exec %{__chmod} -c -x 
 
 
 %check
-%if %{with_tests}
+%if 0%{?with_tests}
     %{__python2} setup.py develop --user
     pushd optional_plugins/html
         %{__python2} setup.py develop --user
@@ -290,12 +322,16 @@ find %{buildroot}%{_docdir}/avocado -type f -name '*.py' -exec %{__chmod} -c -x 
     pushd optional_plugins/resultsdb
         %{__python2} setup.py develop --user
     popd
+    pushd optional_plugins/varianter_yaml_to_mux
+        %{__python2} setup.py develop --user
+    popd
     # Package build environments have the least amount of resources
     # we have observed so far. Let's avoid tests that require too
     # much resources or are time sensitive.
     AVOCADO_CHECK_LEVEL=0 selftests/run
 %endif
 
+
 %files -n python2-%{srcname}
 %license LICENSE
 %doc README.rst
@@ -357,12 +393,22 @@ find %{buildroot}%{_docdir}/avocado -type f -name '*.py' -exec %{__chmod} -c -x 
 %{python2_sitelib}/avocado_framework_plugin_resultsdb-%{version}-py%{python2_version}.egg-info
 
 
+%files -n python2-%{srcname}-plugins-varianter-yaml-to-mux
+%{python2_sitelib}/avocado_varianter_yaml_to_mux/
+%{python2_sitelib}/avocado_framework_plugin_varianter_yaml_to_mux-%{version}-py%{python2_version}.egg-info
+
+
 %files -n python-%{srcname}-examples
 %dir %{_docdir}/avocado
 %{_docdir}/avocado/tests
 %{_docdir}/avocado/wrappers
 
+
 %changelog
+* Wed Jun 14 2017 Merlin Mathesius <mmathesi@redhat.com> - 51.0-1
+- Sync with upstream release 51.0. (BZ#1431413)
+- Disable selftests when libvirt may not be available.
+
 * Wed May 17 2017 Merlin Mathesius <mmathesi@redhat.com> - 50.0-1
 - Sync with upstream release 50.0. (BZ#1431413)
 - Be explicit about selftest level run on check.
diff --git a/sources b/sources
index 2280709..71faaff 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-SHA512 (avocado-50.0.tar.gz) = 0b64e83c5d5bb952ea51e619ea011cac7f0668cf048d89beb265a30996cd3c1c22a43bcfbc1d3f533eec458af0b8bfbe80b5dbe817e8531357bcefc48e867623
+SHA512 (avocado-51.0.tar.gz) = 4367f32302f983b8ac39f11f6c01a3bab78527f1885564b0759acc239e9b87fa3ea7299fc251e697314a5be28107099383300db3bfa2ca9a030372b555a75828