T8518: add unit tests for vyos_vlan module (#471)

Adds 7 unit tests for vyos_vlan covering present, present_no_change,
absent, absent_no_change, aggregate, purge, and address scenarios.
Fixture data moved to dedicated .cfg files under fixtures/.

🤖 Generated by [robots](https://vyos.io)

Co-authored-by: omnom62 <75066712+omnom62@users.noreply.github.com>
Co-authored-by: Daniil Baturin <daniil@baturin.org>

3 files changed, 98 insertions, 42 deletions

diff --git a/tests/unit/modules/network/vyos/fixtures/vyos_vlan_show_interfaces.cfg b/tests/unit/modules/network/vyos/fixtures/vyos_vlan_show_interfaces.cfg
new file mode 100644
index 00000000..b877a4b6
--- /dev/null
+++ b/tests/unit/modules/network/vyos/fixtures/vyos_vlan_show_interfaces.cfg
@@ -0,0 +1,10 @@
+Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
+Interface        IP Address                        S/L  Description
+---------        ----------                        ---  -----------
+eth0             10.0.2.15/24                      u/u
+eth0.100         -                                 u/u  vlan-100
+eth1             -                                 u/u
+eth1.200         192.0.2.1/24                      u/u  vlan-200
+eth2             -                                 u/u
+lo               127.0.0.1/8                       u/u
+                 ::1/128
diff --git a/tests/unit/modules/network/vyos/fixtures/vyos_vlan_show_interfaces_empty.cfg b/tests/unit/modules/network/vyos/fixtures/vyos_vlan_show_interfaces_empty.cfg
new file mode 100644
index 00000000..06ae56a0
--- /dev/null
+++ b/tests/unit/modules/network/vyos/fixtures/vyos_vlan_show_interfaces_empty.cfg
@@ -0,0 +1,7 @@
+Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
+Interface        IP Address                        S/L  Description
+---------        ----------                        ---  -----------
+eth0             10.0.2.15/24                      u/u
+eth1             -                                 u/u
+eth2             -                                 u/u
+lo               127.0.0.1/8                       u/u
diff --git a/tests/unit/modules/network/vyos/test_vyos_vlan.py b/tests/unit/modules/network/vyos/test_vyos_vlan.py
index 4f2ea69a..5bbf87c2 100644
--- a/tests/unit/modules/network/vyos/test_vyos_vlan.py
+++ b/tests/unit/modules/network/vyos/test_vyos_vlan.py
@@ -15,6 +15,7 @@
 # You should have received a copy of the GNU General Public License
 # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
 
+# Make coding more python3-ish
 from __future__ import absolute_import, division, print_function
 
 
@@ -25,21 +26,7 @@ from unittest.mock import patch
 from ansible_collections.vyos.vyos.plugins.modules import vyos_vlan
 from ansible_collections.vyos.vyos.tests.unit.modules.utils import set_module_args
 
-from .vyos_module import TestVyosModule
-
-
-SHOW_INTERFACES_OUTPUT = """\
-Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
-Interface        IP Address                        S/L  Description
----------        ----------                        ---  -----------
-eth0             10.0.2.15/24                      u/u
-eth0.100         -                                 u/u  vlan-100
-eth1             -                                 u/u
-eth1.200         192.0.2.1/24                      u/u  vlan-200
-eth2             -                                 u/u
-lo               127.0.0.1/8                       u/u
-                 ::1/128
-"""
+from .vyos_module import TestVyosModule, load_fixture
 
 
 class TestVyosVlanModule(TestVyosModule):
@@ -65,55 +52,107 @@ class TestVyosVlanModule(TestVyosModule):
 
     def load_fixtures(self, commands=None, filename=None):
         self.load_config.return_value = dict(diff=None, session="session")
-        self.run_commands.return_value = [SHOW_INTERFACES_OUTPUT]
+        if filename == "empty":
+            self.run_commands.return_value = [
+                load_fixture("vyos_vlan_show_interfaces_empty.cfg"),
+            ]
+        else:
+            self.run_commands.return_value = [
+                load_fixture("vyos_vlan_show_interfaces.cfg"),
+            ]
+
+    def test_vyos_vlan_present(self):
+        """Create a new VLAN with a description on eth2 (not in have)."""
+        set_module_args(
+            dict(
+                vlan_id=300,
+                name="vlan-300",
+                interfaces=["eth2"],
+                state="present",
+            )
+        )
+        commands = ["set interfaces ethernet eth2 vif 300 description vlan-300"]
+        self.execute_module(changed=True, commands=commands)
 
-    def test_vyos_vlan_purge_no_bare_interfaces(self):
-        """Purge should only delete VLANs, not bare interfaces without vlan_id."""
+    def test_vyos_vlan_present_no_change(self):
+        """Existing VLAN 100 on eth0 — no commands should be generated."""
         set_module_args(
             dict(
                 vlan_id=100,
+                name="vlan-100",
                 interfaces=["eth0"],
                 state="present",
-                purge=True,
-            ),
+            )
         )
-        result = self.execute_module(changed=True)
-        # Should only delete eth1.200, not bare eth0/eth1/eth2 with vif None
-        for cmd in result.get("commands", []):
-            self.assertNotIn(
-                "vif None",
-                cmd,
-                "Purge generated 'vif None' command for bare interface: {0}".format(cmd),
+        self.execute_module(changed=False, commands=[])
+
+    def test_vyos_vlan_absent(self):
+        """Delete an existing VLAN (200 on eth1)."""
+        set_module_args(
+            dict(
+                vlan_id=200,
+                interfaces=["eth1"],
+                state="absent",
             )
-        # eth1.200 should be purged since it's not in the desired state
-        self.assertIn(
-            "delete interfaces ethernet eth1 vif 200",
-            result.get("commands", []),
         )
+        commands = ["delete interfaces ethernet eth1 vif 200"]
+        self.execute_module(changed=True, commands=commands)
 
-    def test_vyos_vlan_present(self):
+    def test_vyos_vlan_absent_no_change(self):
+        """Delete a VLAN that does not exist — no commands."""
         set_module_args(
             dict(
-                vlan_id=300,
-                name="vlan-300",
-                interfaces=["eth2"],
-                state="present",
-            ),
+                vlan_id=999,
+                interfaces=["eth0"],
+                state="absent",
+            )
+        )
+        self.execute_module(changed=False, commands=[])
+
+    def test_vyos_vlan_aggregate(self):
+        """Create two new VLANs via aggregate; neither is in have."""
+        set_module_args(
+            dict(
+                aggregate=[
+                    dict(vlan_id=301, interfaces=["eth2"], name="vlan-301"),
+                    dict(vlan_id=302, interfaces=["eth2"], name="vlan-302"),
+                ],
+            )
         )
         commands = [
-            "set interfaces ethernet eth2 vif 300 description vlan-300",
+            "set interfaces ethernet eth2 vif 301 description vlan-301",
+            "set interfaces ethernet eth2 vif 302 description vlan-302",
         ]
         self.execute_module(changed=True, commands=commands)
 
-    def test_vyos_vlan_absent(self):
+    def test_vyos_vlan_purge(self):
+        """Purge VLANs not in want. Want only VLAN 100; VLAN 200 should be removed.
+
+        The fixed parser only maps ethX.Y sub-interfaces, so bare ethX interfaces
+        (vlan_id=None) are not in have. Only real VLANs (eth1.200) are purged.
+        """
         set_module_args(
             dict(
                 vlan_id=100,
                 interfaces=["eth0"],
-                state="absent",
-            ),
+                state="present",
+                purge=True,
+            )
         )
         commands = [
-            "delete interfaces ethernet eth0 vif 100",
+            "delete interfaces ethernet eth1 vif 200",
         ]
         self.execute_module(changed=True, commands=commands)
+
+    def test_vyos_vlan_with_address(self):
+        """Create a VLAN with an IP address and no description."""
+        set_module_args(
+            dict(
+                vlan_id=400,
+                address="10.10.40.1/24",
+                interfaces=["eth1"],
+                state="present",
+            )
+        )
+        commands = ["set interfaces ethernet eth1 vif 400 address 10.10.40.1/24"]
+        self.execute_module(changed=True, commands=commands, filename="empty")