etcd3: re-enable and fix tests, add unit tests (#11678)

* etcd3: re-enable and fix tests, add unit tests

- Add unit tests for community.general.etcd3 module (12 tests covering
  state=present/absent, idempotency, check mode, and error paths)
- Fix integration test setup: update etcd binary to v3.6.9 (from v3.2.14),
  download from GitHub releases, add health-check retry loop after start
- Work around etcd3 Python library incompatibility with protobuf >= 4.x
  by setting PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python
- Update to FQCNs throughout integration tests
- Re-enable both etcd3 and lookup_etcd3 integration targets

Fixes https://github.com/ansible-collections/community.general/issues/322

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* improve use of multiple context managers

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/integration/targets/setup_etcd3/tasks/main.yml

@@ -5,89 +5,49 @@
 ####################################################################
 
 # setup etcd3 for integration tests on module/lookup
-# Copyright 2017,  Jean-Philippe Evrard <jean-philippe@evrard.me>
-# Copyright 2020, SCC France, Eric Belhomme <ebelhomme@fr.scc.com>
+# Copyright (c) 2017, Jean-Philippe Evrard <jean-philippe@evrard.me>
+# Copyright (c) 2020, SCC France, Eric Belhomme <ebelhomme@fr.scc.com>
 # GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-# ============================================================
+- name: Install etcd3 Python library
+  ansible.builtin.pip:
+    name: "{{ etcd3_pip_module }}"
+    state: present
 
-# setup etcd3 for supported distros
-- block:
+- name: Check if etcdctl is already usable
+  ansible.builtin.command: "{{ etcd3_path }}/etcdctl --endpoints=localhost:2379 endpoint health"
+  changed_when: false
+  failed_when: false
+  register: etcd3_health_check
 
-    - include_vars: '{{ item }}'
-      with_first_found:
-        - files:
-            - '{{ ansible_facts.distribution }}-{{ ansible_facts.distribution_major_version }}.yml'
-            - '{{ ansible_facts.distribution }}-{{ ansible_facts.distribution_version }}.yml'
-            - '{{ ansible_facts.os_family }}-{{ ansible_facts.distribution_major_version }}.yml'
-            - '{{ ansible_facts.os_family }}.yml'
-            - 'default.yml'
-          paths: '../vars'
+- name: Set up etcd3 binary
+  when: etcd3_health_check.rc != 0
+  block:
+    - name: Ensure clean download directory
+      ansible.builtin.file:
+        path: "{{ etcd3_download_location }}"
+        state: absent
 
-    - name: Upgrade setuptools python2 module
-      pip:
-        name: setuptools<45
-        extra_args: --upgrade
-        state: present
-      when: python_suffix == ''
+    - name: Create download directory
+      ansible.builtin.file:
+        path: "{{ etcd3_download_location }}"
+        state: directory
 
-    - name: Install etcd3 python modules
-      pip:
-        name: "{{ etcd3_pip_module }}"
-        extra_args: --only-binary grpcio
-        state: present
+    - name: Download etcd3
+      ansible.builtin.unarchive:
+        src: "{{ etcd3_download_url }}"
+        dest: "{{ etcd3_download_location }}"
+        remote_src: true
 
-    # Check if re-installing etcd3 is required
-    - name: Check if etcd3ctl exists for reuse.
-      shell: "ETCDCTL_API=3 {{ etcd3_path }}/etcdctl --endpoints=localhost:2379 get foo"
-      args:
-        executable: /bin/bash
+    - name: Start etcd3
+      ansible.builtin.shell: "nohup {{ etcd3_path }}/etcd > /tmp/etcd3.log 2>&1 &"
+      changed_when: true
+
+    - name: Wait for etcd3 to be ready
+      ansible.builtin.command: "{{ etcd3_path }}/etcdctl --endpoints=localhost:2379 endpoint health"
+      register: etcd3_ready
+      until: etcd3_ready.rc == 0
+      retries: 10
+      delay: 3
       changed_when: false
-      failed_when: false
-      register: _testetcd3ctl
-
-    - block:
-      # Installing etcd3
-        - name: If can't reuse, prepare download folder
-          file:
-            path: "{{ etcd3_download_location }}"
-            state: directory
-          register: _etcddownloadexists
-          when:
-            - _testetcd3ctl.rc != 0
-
-        - name: Delete download folder if already exists (to start clean)
-          file:
-            path: "{{ etcd3_download_location }}"
-            state: absent
-          when:
-            - _etcddownloadexists is not changed
-
-        - name: Recreate download folder if purged
-          file:
-            path: "{{ etcd3_download_location }}"
-            state: directory
-          when:
-            - _etcddownloadexists is not changed
-
-        - name: Download etcd3
-          unarchive:
-            src: "{{ etcd3_download_url }}"
-            dest: "{{ etcd3_download_location }}"
-            remote_src: true
-
-        # Running etcd3 and kill afterwards if it wasn't running before.
-        - name: Run etcd3
-          shell: "{{ etcd3_path }}/etcd &"
-          register: _etcd3run
-          changed_when: true
-
-      #    - name: kill etcd3
-      #      command: "pkill etcd"
-
-      when:
-        - _testetcd3ctl.rc != 0
-
-  when:
-    - ansible_facts.distribution | lower ~ "-" ~ ansible_facts.distribution_major_version | lower != 'centos-6'