test: expand coverage 64%→76%; add BUGS.md for Gemini migration issues

tests/test_network.py

@@ -10,12 +10,18 @@ from decnet.network import (
     HOST_IPVLAN_IFACE,
     HOST_MACVLAN_IFACE,
     MACVLAN_NETWORK_NAME,
+    allocate_ips,
     create_ipvlan_network,
     create_macvlan_network,
+    detect_interface,
+    detect_subnet,
+    get_host_ip,
     ips_to_range,
+    remove_macvlan_network,
     setup_host_ipvlan,
     setup_host_macvlan,
     teardown_host_ipvlan,
+    teardown_host_macvlan,
 )
 
 
@@ -193,3 +199,154 @@ class TestSetupHostIpvlan:
         calls = [str(c) for c in mock_run.call_args_list]
         assert any(HOST_IPVLAN_IFACE in c for c in calls)
         assert not any(HOST_MACVLAN_IFACE in c for c in calls)
+
+
+# ---------------------------------------------------------------------------
+# allocate_ips (pure logic — no subprocess / Docker)
+# ---------------------------------------------------------------------------
+
+class TestAllocateIps:
+    def test_basic_allocation(self):
+        ips = allocate_ips("192.168.1.0/24", "192.168.1.1", "192.168.1.100", count=3)
+        assert len(ips) == 3
+        assert "192.168.1.1" not in ips   # gateway skipped
+        assert "192.168.1.100" not in ips # host IP skipped
+
+    def test_skips_network_and_broadcast(self):
+        ips = allocate_ips("10.0.0.0/30", "10.0.0.1", "10.0.0.3", count=1)
+        # /30 hosts: .1 (gateway), .2. .3 is host_ip → only .2 available
+        assert ips == ["10.0.0.2"]
+
+    def test_respects_ip_start(self):
+        ips = allocate_ips("192.168.1.0/24", "192.168.1.1", "192.168.1.1",
+                           count=2, ip_start="192.168.1.50")
+        assert all(ip >= "192.168.1.50" for ip in ips)
+
+    def test_raises_when_not_enough_ips(self):
+        # /30 only has 2 host addresses; reserving both leaves 0
+        with pytest.raises(RuntimeError, match="Not enough free IPs"):
+            allocate_ips("10.0.0.0/30", "10.0.0.1", "10.0.0.2", count=3)
+
+    def test_no_duplicates(self):
+        ips = allocate_ips("10.0.0.0/24", "10.0.0.1", "10.0.0.2", count=10)
+        assert len(ips) == len(set(ips))
+
+    def test_exact_count_returned(self):
+        ips = allocate_ips("172.16.0.0/24", "172.16.0.1", "172.16.0.254", count=5)
+        assert len(ips) == 5
+
+
+# ---------------------------------------------------------------------------
+# detect_interface
+# ---------------------------------------------------------------------------
+
+class TestDetectInterface:
+    @patch("decnet.network._run")
+    def test_parses_dev_from_route(self, mock_run):
+        mock_run.return_value = MagicMock(
+            stdout="default via 192.168.1.1 dev eth0 proto dhcp\n"
+        )
+        assert detect_interface() == "eth0"
+
+    @patch("decnet.network._run")
+    def test_raises_when_no_dev_found(self, mock_run):
+        mock_run.return_value = MagicMock(stdout="")
+        with pytest.raises(RuntimeError, match="Could not auto-detect"):
+            detect_interface()
+
+
+# ---------------------------------------------------------------------------
+# detect_subnet
+# ---------------------------------------------------------------------------
+
+class TestDetectSubnet:
+    def _make_run(self, addr_output, route_output):
+        def side_effect(cmd, **kwargs):
+            if "addr" in cmd:
+                return MagicMock(stdout=addr_output)
+            return MagicMock(stdout=route_output)
+        return side_effect
+
+    @patch("decnet.network._run")
+    def test_parses_subnet_and_gateway(self, mock_run):
+        mock_run.side_effect = self._make_run(
+            "    inet 192.168.1.5/24 brd 192.168.1.255 scope global eth0\n",
+            "default via 192.168.1.1 dev eth0\n",
+        )
+        subnet, gw = detect_subnet("eth0")
+        assert subnet == "192.168.1.0/24"
+        assert gw == "192.168.1.1"
+
+    @patch("decnet.network._run")
+    def test_raises_when_no_inet(self, mock_run):
+        mock_run.side_effect = self._make_run("", "default via 192.168.1.1 dev eth0\n")
+        with pytest.raises(RuntimeError, match="Could not detect subnet"):
+            detect_subnet("eth0")
+
+    @patch("decnet.network._run")
+    def test_raises_when_no_gateway(self, mock_run):
+        mock_run.side_effect = self._make_run(
+            "    inet 192.168.1.5/24 brd 192.168.1.255 scope global eth0\n", ""
+        )
+        with pytest.raises(RuntimeError, match="Could not detect gateway"):
+            detect_subnet("eth0")
+
+
+# ---------------------------------------------------------------------------
+# get_host_ip
+# ---------------------------------------------------------------------------
+
+class TestGetHostIp:
+    @patch("decnet.network._run")
+    def test_returns_host_ip(self, mock_run):
+        mock_run.return_value = MagicMock(
+            stdout="    inet 10.0.0.5/24 brd 10.0.0.255 scope global eth0\n"
+        )
+        assert get_host_ip("eth0") == "10.0.0.5"
+
+    @patch("decnet.network._run")
+    def test_raises_when_no_inet(self, mock_run):
+        mock_run.return_value = MagicMock(stdout="link/ether aa:bb:cc:dd:ee:ff\n")
+        with pytest.raises(RuntimeError, match="Could not determine host IP"):
+            get_host_ip("eth0")
+
+
+# ---------------------------------------------------------------------------
+# remove_macvlan_network
+# ---------------------------------------------------------------------------
+
+class TestRemoveMacvlanNetwork:
+    def test_removes_matching_network(self):
+        client = MagicMock()
+        net = MagicMock()
+        net.name = MACVLAN_NETWORK_NAME
+        client.networks.list.return_value = [net]
+        remove_macvlan_network(client)
+        net.remove.assert_called_once()
+
+    def test_noop_when_no_matching_network(self):
+        client = MagicMock()
+        other = MagicMock()
+        other.name = "some-other-network"
+        client.networks.list.return_value = [other]
+        remove_macvlan_network(client)
+        other.remove.assert_not_called()
+
+
+# ---------------------------------------------------------------------------
+# teardown_host_macvlan
+# ---------------------------------------------------------------------------
+
+class TestTeardownHostMacvlan:
+    @patch("decnet.network.os.geteuid", return_value=0)
+    @patch("decnet.network._run")
+    def test_deletes_macvlan_iface(self, mock_run, _):
+        mock_run.return_value = MagicMock(returncode=0)
+        teardown_host_macvlan("192.168.1.96/27")
+        calls = [str(c) for c in mock_run.call_args_list]
+        assert any(HOST_MACVLAN_IFACE in c for c in calls)
+
+    @patch("decnet.network.os.geteuid", return_value=1)
+    def test_requires_root(self, _):
+        with pytest.raises(PermissionError):
+            teardown_host_macvlan("192.168.1.96/27")