diff --git a/roles/common/molecule/default/tests/test_default.py b/roles/common/molecule/default/tests/test_default.py
index 4d34e78064feec4ddb6a088edaf0730f6182576f..885114d13da4ad567a831187fcb786fcf37c3d9f 100644
--- a/roles/common/molecule/default/tests/test_default.py
+++ b/roles/common/molecule/default/tests/test_default.py
@@ -328,7 +328,7 @@ def test_pipreqcheck_virtualenv_packages(host, pip_path, expected_packages):
     requirements checks..
     """
 
-    packages = host.run("sudo -u %s %s freeze --all" % ('pipreqcheck', pip_path))
+    packages = host.run("sudo -u pipreqcheck %s freeze --all", pip_path)
 
     # Normalise package names and order.
     expected_packages = sorted([p.lower() for p in expected_packages])
diff --git a/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_client.py b/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_client.py
index d889bfa24a219a3aac944213115e5d44ef03ea0b..703495cfde964c03e2f38a7dd6f29addc6bec518 100644
--- a/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_client.py
+++ b/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_client.py
@@ -23,6 +23,6 @@ def test_connectivity_from_client(host, server):
 
     with host.sudo():
 
-        ping = host.run('hping3 -S -p 25 -c 1 %s' % server)
+        ping = host.run('hping3 -S -p 25 -c 1 %s', server)
         assert ping.rc != 0
         assert "100% packet loss" in ping.stderr
diff --git a/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_relay.py b/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_relay.py
index 74a5c426566db57b5ea18cc0c40d78f7b02a6352..251a17182eb940ce7185c4298323d8220b96e8b8 100644
--- a/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_relay.py
+++ b/roles/mail_forwarder/molecule/default/tests/test_connectivity_from_relay.py
@@ -21,7 +21,7 @@ def test_connectivity_from_authorised_relay(host, server):
 
     with host.sudo():
 
-        ping = host.run('hping3 -S -p 25 -c 1 %s' % server)
+        ping = host.run('hping3 -S -p 25 -c 1 %s', server)
         assert ping.rc == 0
 
 
@@ -37,7 +37,7 @@ def test_connectivity_from_unauthorised_relay(host, server):
 
     with host.sudo():
 
-        ping = host.run('hping3 -S -p 25 -c 1 %s' % server)
+        ping = host.run('hping3 -S -p 25 -c 1 %s', server)
         assert ping.rc != 0
         assert "100% packet loss" in ping.stderr
 
@@ -63,6 +63,6 @@ def test_open_relay(host, server):
 
     no_recipients_accepted_error_code = 24
 
-    send = host.run('swaks --suppress-data --to root@client1 --server %s' % server)
+    send = host.run('swaks --suppress-data --to root@client1 --server %s', server)
     assert send.rc == no_recipients_accepted_error_code
     assert "Relay access denied" in send.stdout
diff --git a/roles/web_server/molecule/default/tests/test_client.py b/roles/web_server/molecule/default/tests/test_client.py
index 28260db64a016a346b35f1e9d9d9fd4bd06c1c52..0c91ec29f381f327bbd7d06d02b1c9cb5b98dad0 100644
--- a/roles/web_server/molecule/default/tests/test_client.py
+++ b/roles/web_server/molecule/default/tests/test_client.py
@@ -19,5 +19,5 @@ def test_connectivity(host):
             # HTTP, HTTPS.
             for port in [80, 443]:
 
-                ping = host.run('hping3 -S -p %d -c 1 %s' % (port, server))
+                ping = host.run('hping3 -S -p %s -c 1 %s', str(port), server)
                 assert ping.rc == 0
diff --git a/roles/wsgi_website/molecule/default/tests/test_default.py b/roles/wsgi_website/molecule/default/tests/test_default.py
index ae9fe0c457afa5549767cfc16513c3e25d1f5021..65c9066c8e48d4e4e043c560dc2dafdc3672a4f7 100644
--- a/roles/wsgi_website/molecule/default/tests/test_default.py
+++ b/roles/wsgi_website/molecule/default/tests/test_default.py
@@ -291,7 +291,7 @@ def test_python_virtualenv_wrapper_script(host, wrapper_script, expected_owner,
         assert wrapper.group == expected_group
         assert wrapper.mode == 0o750
 
-        command = host.run("sudo -u %s %s python -c 'import gunicorn'" % (expected_owner, wrapper_script))
+        command = host.run("sudo -u %s %s python -c 'import gunicorn'", expected_owner, wrapper_script)
         assert command.rc == 0
 
 
@@ -333,7 +333,7 @@ def test_virtualenv_packages(host, admin_user, pip_path, expected_packages):
     Tests if correct packages are installed in virtualenv.
     """
 
-    packages = host.run("sudo -u %s %s freeze" % (admin_user, pip_path))
+    packages = host.run("sudo -u %s %s freeze", admin_user, pip_path)
 
     # Normalise package names and order.
     expected_packages = sorted([p.lower() for p in expected_packages])
diff --git a/roles/xmpp_server/molecule/default/tests/test_client.py b/roles/xmpp_server/molecule/default/tests/test_client.py
index 1060b11765bdafb33bbd3c49c5ce27e1397512ac..4eeda8e5f2f2a4f5e385c59b1a9f0904df0676af 100644
--- a/roles/xmpp_server/molecule/default/tests/test_client.py
+++ b/roles/xmpp_server/molecule/default/tests/test_client.py
@@ -19,7 +19,7 @@ def test_connectivity(host):
             # c2s plaintext, c2s TLS, file proxy, s2s.
             for port in [5222, 5223, 5000, 5269]:
 
-                ping = host.run('hping3 -S -p %d -c 1 %s' % (port, server))
+                ping = host.run('hping3 -S -p %s -c 1 %s', str(port), server)
                 assert ping.rc == 0