feat: apt's proxy on a Proxmox VE node (NetOrk/netork#1397)

The node is Debian: AptProxyMixin gives it get_package_proxy(),
get_package_proxy_report(), check_package_proxy() and the fix
configure_package_proxy(), as on any Debian host. Logged in as root, the
transports are the exec path; the file is written without an exit inside
_rc's braces, which would end the shell before the status (see #30).

Requires napalm-device-types 4.22.0; version 0.7.0.

tests/test_fix_templates.py

@@ -116,3 +116,77 @@ class TestPackages:
 def test_the_old_actions_are_gone():
     for name in ("run_device_action", "_action_fix_snmp", "_action_install_lldpd"):
         assert not hasattr(ProxmoxDriver, name), name
+
+
+_APT_REPORT = (
+    "APROXY_BEGIN\n[dump]\n{dump}[parts]\n{parts}[main]\n[sources]\n"
+    "http://download.proxmox.com/debian/pve/dists/trixie/\nAPROXY_END\n"
+)
+
+
+class _AptNode(_Node):
+    """A node that answers apt's proxy report and a fetch."""
+
+    def __init__(self, proxy="", parts=""):
+        super().__init__()
+        self.proxy = proxy
+        self.parts = parts
+
+    def __call__(self, command: str) -> str:
+        if "apt-config dump" in command:
+            self.ran.append(command)
+            dump = f'Acquire::http::Proxy "{self.proxy}";\n' if self.proxy else ""
+            return _APT_REPORT.format(dump=dump, parts=self.parts)
+        if "apt-helper" in command:
+            self.ran.append(command)
+            return "APROXY_BEGIN\n[fetch]\nGet:1 x\n[rc]\n0\n[match]\n2\nAPROXY_END\n"
+        return super().__call__(command)
+
+
+class TestPackageProxy:
+    """Proxmox VE is Debian: apt's proxy is set and read as on any Debian host (netOrk #1397)."""
+
+    def test_it_takes_the_fix(self):
+        assert callable(getattr(ProxmoxDriver, "configure_package_proxy", None))
+
+    def test_the_fact(self):
+        d = ProxmoxDriver("pve", "root@pam", "pw")
+        d._exec_ssh_command = _AptNode(proxy="http://c:3142")
+
+        assert d.get_package_proxy() == "http://c:3142"
+
+    def test_written_as_root_read_back_and_fetched_through(self):
+        node = _AptNode(proxy="http://c:3142")
+        d = ProxmoxDriver("pve", "root@pam", "pw")
+        d._exec_ssh_command = node
+
+        result = d.configure_package_proxy("http://c:3142")
+
+        assert result["success"] is True, result["output"]
+        write = next(c for c in node.ran if "/etc/apt/apt.conf.d/00proxy" in c)
+        assert "install -m 644" in write
+        b64 = re.search(r"echo ([A-Za-z0-9+/=]+) \| base64 -d", write).group(1)
+        import base64
+
+        assert base64.b64decode(b64).decode() == 'Acquire::http::Proxy "http://c:3142";\n'
+        assert any("dists/trixie/InRelease" in c for c in node.ran)
+
+    def test_another_proxy_is_commented_out(self):
+        node = _AptNode(
+            proxy="http://c:3142",
+            parts='/etc/apt/apt.conf.d/90curtin-aptproxy:1:Acquire::http::Proxy "http://old:3128";\n',
+        )
+        d = ProxmoxDriver("pve", "root@pam", "pw")
+        d._exec_ssh_command = node
+
+        d.configure_package_proxy("http://c:3142")
+
+        assert any(c.startswith("{ sed -i -e '1{") for c in node.ran)
+
+    def test_the_proxy_answers(self):
+        d = ProxmoxDriver("pve", "root@pam", "pw")
+        d._exec_ssh_command = _AptNode()
+
+        result = d.check_package_proxy("http://c:3142/acng-report.html", expect="Cache")
+
+        assert result == {"reachable": True, "expected": True, "error": ""}