tests: Do not use ansible_interfaces

ansible_interfaces requires iproute to be present which might not be the
case for container images. Check /sys/class/net to avoid the dependency.

tests/tasks/assert-device_absent.yml

@@ -1,9 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 ---
-# need to run setup again when this is just a task to ensure ansible_interfaces
-# is current
-- setup:
+- include: get-interface_stat.yml
 - name: "assert that interface {{ interface }} is absent"
   assert:
-    that: "{{ not interface in ansible_interfaces }}"
-    msg: "{{ interface }} is in ansible_interfaces: {{ ansible_interfaces }}"
+    that: not interface_stat.stat.exists
+    msg: "{{ interface }} exists"

tests/tasks/assert-device_present.yml

@@ -1,9 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 ---
-# need to run setup again when this is just a task to ensure ansible_interfaces
-# is current
-- setup:
+- include: get-interface_stat.yml
 - name: "assert that interface {{ interface }} is present"
   assert:
-    that: "{{ interface in ansible_interfaces }}"
-    msg: "{{ interface }} is not in ansible_interfaces: {{ ansible_interfaces }}"
+    that: interface_stat.stat.exists
+    msg: "{{ interface }} does not exist"

tests/tasks/get-current_interfaces.yml

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: BSD-3-Clause
+---
+- command: ls -1
+  args:
+    chdir: /sys/class/net
+  register: _current_interfaces
+- set_fact:
+    current_interfaces: "{{ _current_interfaces.stdout_lines }}"

tests/tasks/get-interface_stat.yml

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: BSD-3-Clause
+---
+- name: "Get stat for interface {{ interface }}"
+  stat:
+    get_attributes: false
+    get_checksum: false
+    get_mime: false
+    path: "/sys/class/net/{{ interface }}"
+  register: interface_stat

tests/tasks/manage-test-interface.yml

@@ -8,32 +8,38 @@
     msg: "type needs to be dummy, tap or veth, not '{{ type }}'"
   when: type not in ["dummy", "tap", "veth"]
 
-# run setup again to make sure ansible_interfaces is accurate
-- setup:
+# - include: get-current_interfaces.yml
+- include: show-interfaces.yml
 
-  # veth
+# veth
 - name: Create veth interface {{ interface }}
   shell: ip link add {{ interface }} type veth peer name peer{{ interface }}
-  when: "type == 'veth' and state == 'present' and interface not in ansible_interfaces"
+  when: "type == 'veth' and state == 'present' and
+         interface not in current_interfaces"
 
 - name: Delete veth interface {{ interface }}
   shell: ip link del {{ interface }} type veth
-  when: "type == 'veth' and state == 'absent' and interface in ansible_interfaces"
+  when: "type == 'veth' and state == 'absent' and
+         interface in current_interfaces"
 
-  # dummy
+# dummy
 - name: Create dummy interface {{ interface }}
   shell: ip link add "{{ interface }}" type dummy
-  when: "type == 'dummy' and state == 'present' and interface not in ansible_interfaces"
+  when: "type == 'dummy' and state == 'present' and
+         interface not in current_interfaces"
 
 - name: Delete dummy interface {{ interface }}
   shell: ip link del "{{ interface }}" type dummy
-  when: "type == 'dummy' and state == 'absent' and interface in ansible_interfaces"
+  when: "type == 'dummy' and state == 'absent' and
+         interface in current_interfaces"
 
-  # tap
+# tap
 - name: Create tap interface {{ interface }}
   shell: ip tuntap add dev {{ interface }} mode tap
-  when: "type == 'tap' and state == 'present' and interface not in ansible_interfaces"
+  when: "type == 'tap' and state == 'present'
+         and interface not in current_interfaces"
 
 - name: Delete tap interface {{ interface }}
   shell: ip tuntap del dev {{ interface }} mode tap
-  when: "type == 'tap' and state == 'absent' and interface in ansible_interfaces"
+  when: "type == 'tap' and state == 'absent' and
+         interface in current_interfaces"

tests/tasks/show-interfaces.yml

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: BSD-3-Clause
 ---
+- include: get-current_interfaces.yml
 - debug:
-    msg: "ansible_interfaces: {{ ansible_interfaces }}"
+    msg: "current_interfaces: {{ current_interfaces }}"