Fix for Python 3.10 (#329)

diff --git a/tests/lib/test_build.py b/tests/lib/test_build.py
index 901e8ed..df3f943 100644
--- a/tests/lib/test_build.py
+++ b/tests/lib/test_build.py
@@ -2,7 +2,7 @@
 if __name__ == '__main__':
     import sys, os, distutils.util
     build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
+    build_lib_ext = os.path.join('build', 'lib.{}-{}.{}'.format(distutils.util.get_platform(), *sys.version_info))
     sys.path.insert(0, build_lib)
     sys.path.insert(0, build_lib_ext)
     import test_yaml, test_appliance
diff --git a/tests/lib/test_build_ext.py b/tests/lib/test_build_ext.py
index ff195d5..fa843f6 100644
--- a/tests/lib/test_build_ext.py
+++ b/tests/lib/test_build_ext.py
@@ -3,7 +3,7 @@
 if __name__ == '__main__':
     import sys, os, distutils.util
     build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
+    build_lib_ext = os.path.join('build', 'lib.{}-{}.{}'.format(distutils.util.get_platform(), *sys.version_info))
     sys.path.insert(0, build_lib)
     sys.path.insert(0, build_lib_ext)
     import test_yaml_ext, test_appliance
diff --git a/tests/lib3/test_build.py b/tests/lib3/test_build.py
index 901e8ed..df3f943 100644
--- a/tests/lib3/test_build.py
+++ b/tests/lib3/test_build.py
@@ -2,7 +2,7 @@
 if __name__ == '__main__':
     import sys, os, distutils.util
     build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
+    build_lib_ext = os.path.join('build', 'lib.{}-{}.{}'.format(distutils.util.get_platform(), *sys.version_info))
     sys.path.insert(0, build_lib)
     sys.path.insert(0, build_lib_ext)
     import test_yaml, test_appliance
diff --git a/tests/lib3/test_build_ext.py b/tests/lib3/test_build_ext.py
index ff195d5..fa843f6 100644
--- a/tests/lib3/test_build_ext.py
+++ b/tests/lib3/test_build_ext.py
@@ -3,7 +3,7 @@
 if __name__ == '__main__':
     import sys, os, distutils.util
     build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
+    build_lib_ext = os.path.join('build', 'lib.{}-{}.{}'.format(distutils.util.get_platform(), *sys.version_info))
     sys.path.insert(0, build_lib)
     sys.path.insert(0, build_lib_ext)
     import test_yaml_ext, test_appliance