diff --git a/roles/backup/handlers/main.yml b/roles/backup/handlers/main.yml
index 680de1fd07c4adabaf6a1c934799439b9152a678..c0bee1ff4dcfdc621f85de7c2d238d143a9fc00c 100644
--- a/roles/backup/handlers/main.yml
+++ b/roles/backup/handlers/main.yml
@@ -7,4 +7,4 @@
     owner: root
     group: root
     mode: 0600
-    backup: yes
+    backup: true
diff --git a/roles/backup/meta/main.yml b/roles/backup/meta/main.yml
index 6d3e2a61165ec06b293df864d787356dc08d55a2..6e411ef0a87cbf16212ee9f85165d74aeff2b942 100644
--- a/roles/backup/meta/main.yml
+++ b/roles/backup/meta/main.yml
@@ -1,6 +1,6 @@
 ---
 
-allow_duplicates: yes
+allow_duplicates: true
 
 dependencies:
   - backup_client
diff --git a/roles/backup/molecule/default/create.yml b/roles/backup/molecule/default/create.yml
index f8eb37cd4df02c540216c02791d0c50870986202..ce8657f9bae3be7f42731fd1efe77e87a62afcd9 100644
--- a/roles/backup/molecule/default/create.yml
+++ b/roles/backup/molecule/default/create.yml
@@ -2,7 +2,7 @@
 - name: Create
   hosts: localhost
   connection: local
-  gather_facts: False
+  gather_facts: false
   no_log: "{{ not lookup('env', 'MOLECULE_DEBUG') | bool }}"
   vars:
     molecule_file: "{{ lookup('env', 'MOLECULE_FILE') }}"
diff --git a/roles/backup/molecule/default/destroy.yml b/roles/backup/molecule/default/destroy.yml
index 3972a2df8fafe515b30a74f951499b83aae8449c..8f0a3703672765e77f4f1a3a8046a1f2b561a7a8 100644
--- a/roles/backup/molecule/default/destroy.yml
+++ b/roles/backup/molecule/default/destroy.yml
@@ -3,7 +3,7 @@
 - name: Destroy
   hosts: localhost
   connection: local
-  gather_facts: False
+  gather_facts: false
   no_log: "{{ not lookup('env', 'MOLECULE_DEBUG') | bool }}"
   vars:
     molecule_file: "{{ lookup('env', 'MOLECULE_FILE') }}"
diff --git a/roles/backup/molecule/default/group_vars/parameters-mandatory.yml b/roles/backup/molecule/default/group_vars/parameters-mandatory.yml
new file mode 100644
index 0000000000000000000000000000000000000000..520dcaee1d8661283ea0a777a2c3a797ba7d5f01
--- /dev/null
+++ b/roles/backup/molecule/default/group_vars/parameters-mandatory.yml
@@ -0,0 +1,13 @@
+---
+
+backup_patterns_filename: "test"
+
+# backup_client role parameters.
+backup_encryption_key: "{{ lookup('file', 'tests/data/gnupg/parameters-mandatory.asc') }}"
+backup_server: 10.31.127.10
+backup_server_host_ssh_public_keys:
+  - "{{ lookup('file', 'tests/data/ssh/server_dsa.pub') }}"
+  - "{{ lookup('file', 'tests/data/ssh/server_rsa.pub') }}"
+  - "{{ lookup('file', 'tests/data/ssh/server_ed25519.pub') }}"
+  - "{{ lookup('file', 'tests/data/ssh/server_ecdsa.pub') }}"
+backup_ssh_key: "{{ lookup('file', 'tests/data/ssh/parameters-mandatory' ) }}"
diff --git a/roles/backup/molecule/default/group_vars/parameters-optional.yml b/roles/backup/molecule/default/group_vars/parameters-optional.yml
new file mode 100644
index 0000000000000000000000000000000000000000..14693dfc12f6849b837bdc50602ad5dd3c3fc70e
--- /dev/null
+++ b/roles/backup/molecule/default/group_vars/parameters-optional.yml
@@ -0,0 +1,17 @@
+---
+
+backup_patterns_filename: "test"
+backup_patterns:
+  - /etc/hosts
+  - /etc/ethers
+  - /var/log
+
+# backup_client role parameters.
+backup_encryption_key: "{{ lookup('file', 'tests/data/gnupg/parameters-optional.asc') }}"
+backup_server: 10.31.127.10
+backup_server_host_ssh_public_keys:
+  - "{{ lookup('file', 'tests/data/ssh/server_dsa.pub') }}"
+  - "{{ lookup('file', 'tests/data/ssh/server_rsa.pub') }}"
+  - "{{ lookup('file', 'tests/data/ssh/server_ed25519.pub') }}"
+  - "{{ lookup('file', 'tests/data/ssh/server_ecdsa.pub') }}"
+backup_ssh_key: "{{ lookup('file', 'tests/data/ssh/parameters-mandatory' ) }}"
diff --git a/roles/backup/molecule/default/molecule.yml b/roles/backup/molecule/default/molecule.yml
index cab3cf35b8c91b686e4dff2cb5f903b45ded876a..020b4c42adbf474a57b931f42bd2c5e81b157309 100644
--- a/roles/backup/molecule/default/molecule.yml
+++ b/roles/backup/molecule/default/molecule.yml
@@ -9,6 +9,8 @@ driver:
 
 lint:
   name: yamllint
+  options:
+    config-file: ../../.yamllint.yml
 
 platforms:
 
diff --git a/roles/backup/molecule/default/playbook.yml b/roles/backup/molecule/default/playbook.yml
index 526735e77492a7ce5b54735a8725b0806b5c274d..ed8fe429883e872585a74322f8a021a03d24487f 100644
--- a/roles/backup/molecule/default/playbook.yml
+++ b/roles/backup/molecule/default/playbook.yml
@@ -1,38 +1,6 @@
 ---
 
-- hosts: parameters-mandatory
-  become: yes
+- hosts: parameters-mandatory,parameters-optional
+  become: true
   roles:
-    - role: backup
-      backup_patterns_filename: "test"
-  vars:
-    # Required for backup_client role which is part of meta dependencies.
-    backup_encryption_key: "{{ lookup('file', 'tests/data/gnupg/parameters-mandatory.asc') }}"
-    backup_server: 10.31.127.10
-    backup_server_host_ssh_public_keys:
-      - "{{ lookup('file', 'tests/data/ssh/server_dsa.pub') }}"
-      - "{{ lookup('file', 'tests/data/ssh/server_rsa.pub') }}"
-      - "{{ lookup('file', 'tests/data/ssh/server_ed25519.pub') }}"
-      - "{{ lookup('file', 'tests/data/ssh/server_ecdsa.pub') }}"
-    backup_ssh_key: "{{ lookup('file', 'tests/data/ssh/parameters-mandatory' ) }}"
-
-
-- hosts: parameters-optional
-  become: yes
-  roles:
-    - role: backup
-      backup_patterns_filename: "test"
-      backup_patterns:
-        - /etc/hosts
-        - /etc/ethers
-        - /var/log
-  vars:
-    # Required for backup_client role which is part of meta dependencies.
-    backup_encryption_key: "{{ lookup('file', 'tests/data/gnupg/parameters-optional.asc') }}"
-    backup_server: 10.31.127.10
-    backup_server_host_ssh_public_keys:
-      - "{{ lookup('file', 'tests/data/ssh/server_dsa.pub') }}"
-      - "{{ lookup('file', 'tests/data/ssh/server_rsa.pub') }}"
-      - "{{ lookup('file', 'tests/data/ssh/server_ed25519.pub') }}"
-      - "{{ lookup('file', 'tests/data/ssh/server_ecdsa.pub') }}"
-    backup_ssh_key: "{{ lookup('file', 'tests/data/ssh/parameters-mandatory' ) }}"
+    - backup
diff --git a/roles/backup/molecule/default/prepare.yml b/roles/backup/molecule/default/prepare.yml
index 2ca5369027ee16118496dcf8548f8d803a0c9699..ecfa6db10c57f61e118e827fb3a95abf2159de8c 100644
--- a/roles/backup/molecule/default/prepare.yml
+++ b/roles/backup/molecule/default/prepare.yml
@@ -2,18 +2,18 @@
 
 - name: Prepare
   hosts: all
-  gather_facts: False
+  gather_facts: false
   tasks:
     - name: Install python for Ansible
       raw: test -e /usr/bin/python || (apt -y update && apt install -y python-minimal)
-      become: True
-      changed_when: False
+      become: true
+      changed_when: false
 
 - hosts: all
-  become: yes
+  become: true
   tasks:
 
     - name: Update all caches to avoid errors due to missing remote archives
       apt:
-        update_cache: yes
-      changed_when: False
+        update_cache: true
+      changed_when: false
diff --git a/roles/backup/molecule/default/tests/test_default.py b/roles/backup/molecule/default/tests/test_default.py
index 077de93d4e69ee8dbf9eee9b66c5f11af1dfad5c..a88e93ab286331bcfc9104a8c4f23958299e8d0c 100644
--- a/roles/backup/molecule/default/tests/test_default.py
+++ b/roles/backup/molecule/default/tests/test_default.py
@@ -1,8 +1,10 @@
+import os
+
 import testinfra.utils.ansible_runner
 
 
 testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
-    '.molecule/ansible_inventory.yml').get_hosts('all')
+    os.environ['MOLECULE_INVENTORY_FILE']).get_hosts(['parameters-mandatory', 'parameters-optional'])
 
 
 def test_backup_patterns_file(host):
diff --git a/roles/backup/molecule/default/tests/test_parameters_mandatory.py b/roles/backup/molecule/default/tests/test_parameters_mandatory.py
index af520a4056450972ec6128c35f7e8458478e2bc8..29d9fe6f0b56257b34f51a5c539ac50187c6a16b 100644
--- a/roles/backup/molecule/default/tests/test_parameters_mandatory.py
+++ b/roles/backup/molecule/default/tests/test_parameters_mandatory.py
@@ -1,8 +1,10 @@
+import os
+
 import testinfra.utils.ansible_runner
 
 
 testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
-    '.molecule/ansible_inventory.yml').get_hosts('parameters-mandatory')
+    os.environ['MOLECULE_INVENTORY_FILE']).get_hosts(['parameters-mandatory'])
 
 
 def test_backup_patterns_content(host):
diff --git a/roles/backup/molecule/default/tests/test_parameters_optional.py b/roles/backup/molecule/default/tests/test_parameters_optional.py
index 267fe39704d0f9acbddc54cc7761ca1333894e62..04a606b2a5a061e704732e6f6bdcca3e79c89c96 100644
--- a/roles/backup/molecule/default/tests/test_parameters_optional.py
+++ b/roles/backup/molecule/default/tests/test_parameters_optional.py
@@ -1,8 +1,10 @@
+import os
+
 import testinfra.utils.ansible_runner
 
 
 testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
-    '.molecule/ansible_inventory.yml').get_hosts('parameters-optional')
+    os.environ['MOLECULE_INVENTORY_FILE']).get_hosts(['parameters-optional'])
 
 
 def test_backup_patterns_content(host):