diff --git a/roles/preseed/tests/test_parameters_optional.py b/roles/preseed/tests/test_parameters_optional.py
new file mode 100644
index 0000000000000000000000000000000000000000..42f2103a104ad92c166e4be5c6ef7da52050ed7d
--- /dev/null
+++ b/roles/preseed/tests/test_parameters_optional.py
@@ -0,0 +1,76 @@
+import os
+
+import testinfra.utils.ansible_runner
+
+
+testinfra_hosts = testinfra.utils.ansible_runner.AnsibleRunner(
+    '.molecule/ansible_inventory').get_hosts('parameters-optional')
+
+
+PRESEED_DIRECTORY = '/tmp/custom_preseed_files_location'
+
+
+def test_preseed_directory(File, Sudo):
+    """
+    Test presence and permissions of preseed directory.
+    """
+
+    with Sudo():
+
+        preseed_directory = File(PRESEED_DIRECTORY)
+
+        assert preseed_directory.is_directory
+        assert preseed_directory.mode == 0o750
+
+
+def test_preseed_configuration_files(File, Sudo, TestinfraBackend):
+    """
+    Tests presence and permissions on created preseed configuration files.
+    """
+
+    with Sudo():
+
+        # Verify that preseed configuration files are created for all hosts.
+        for host in testinfra_hosts:
+
+            preseed_file = File(os.path.join(PRESEED_DIRECTORY, "%s.cfg" % host))
+
+            assert preseed_file.is_file
+            assert preseed_file.mode == 0o640
+
+
+def test_preseed_configuration_file_content(File, Sudo, TestinfraBackend):
+    """
+    Tests content of generated preseed configuration file.
+    """
+
+    with Sudo():
+        preseed_file = File(os.path.join(PRESEED_DIRECTORY, "%s.cfg" % TestinfraBackend.get_hostname()))
+        preseed_file_content = preseed_file.content_string
+        ssh_public_key = "CUSTOMKEY"
+
+    assert "d-i debian-installer/language string sr" in preseed_file_content
+    assert "d-i debian-installer/country string RS" in preseed_file_content
+    assert "d-i debian-installer/locale string en_UK.UTF-8" in preseed_file_content
+    assert "d-i keyboard-configuration/xkb-keymap select sv" in preseed_file_content
+    assert "d-i netcfg/choose_interface select eth1" in preseed_file_content
+
+    assert """# Manual network configuration.
+d-i netcfg/disable_autoconfig boolean true
+d-i netcfg/get_ipaddress string 3.3.3.3
+d-i netcfg/get_netmask string 255.255.0.0
+d-i netcfg/get_gateway string 2.2.2.2
+d-i netcfg/get_nameservers string 1.1.1.1
+d-i netcfg/confirm_static boolean true
+
+# Hostname and domain configuration.
+d-i netcfg/get_hostname string testing
+d-i netcfg/get_domain string example.com""" in preseed_file_content
+
+    assert "d-i mirror/http/hostname string ftp.de.debian.org" in preseed_file_content
+    assert "d-i mirror/http/directory string /" in preseed_file_content
+    assert "d-i mirror/http/proxy string http://proxy.local" in preseed_file_content
+    assert "d-i passwd/root-password password myrootpassword" in preseed_file_content
+    assert "d-i passwd/root-password-again password myrootpassword" in preseed_file_content
+    assert "d-i time/zone string Europe/Belgrade" in preseed_file_content
+    assert ssh_public_key in preseed_file_content