Testing: Stabilized test suite and achieved 93% total coverage.

- Fixed CLI tests by patching local imports at source (psutil, os, Path).
- Fixed Collector tests by globalizing docker.from_env mock.
- Stabilized SSE stream tests via AsyncMock and immediate generator termination to prevent hangs.
- Achieved >80% coverage on CLI (84%), Collector (97%), and DB Repository (100%).
- Implemented SMTP Relay service tests (100%).

tests/test_fleet.py

@@ -0,0 +1,192 @@
+"""
+Tests for decnet/fleet.py — fleet builder logic.
+
+Covers build_deckies, build_deckies_from_ini, resolve_distros,
+and edge cases like IP exhaustion and missing services.
+"""
+
+import pytest
+
+from decnet.archetypes import get_archetype
+from decnet.fleet import (
+    all_service_names,
+    build_deckies,
+    build_deckies_from_ini,
+    resolve_distros,
+)
+from decnet.ini_loader import IniConfig, DeckySpec
+
+
+# ── resolve_distros ───────────────────────────────────────────────────────────
+
+class TestResolveDistros:
+    def test_explicit_distros_cycled(self):
+        result = resolve_distros(["debian", "ubuntu22"], False, 5)
+        assert result == ["debian", "ubuntu22", "debian", "ubuntu22", "debian"]
+
+    def test_explicit_single_distro(self):
+        result = resolve_distros(["rocky9"], False, 3)
+        assert result == ["rocky9", "rocky9", "rocky9"]
+
+    def test_randomize_returns_correct_count(self):
+        result = resolve_distros(None, True, 4)
+        assert len(result) == 4
+        # All returned slugs should be valid distro slugs
+        from decnet.distros import all_distros
+        valid = set(all_distros().keys())
+        for slug in result:
+            assert slug in valid
+
+    def test_archetype_preferred_distros(self):
+        arch = get_archetype("deaddeck")
+        result = resolve_distros(None, False, 3, archetype=arch)
+        for slug in result:
+            assert slug in arch.preferred_distros
+
+    def test_fallback_cycles_all_distros(self):
+        result = resolve_distros(None, False, 2)
+        from decnet.distros import all_distros
+        slugs = list(all_distros().keys())
+        assert result[0] == slugs[0]
+        assert result[1] == slugs[1]
+
+
+# ── build_deckies ─────────────────────────────────────────────────────────────
+
+class TestBuildDeckies:
+    _IPS: list[str] = ["192.168.1.10", "192.168.1.11", "192.168.1.12"]
+
+    def test_explicit_services(self):
+        deckies = build_deckies(3, self._IPS, ["ssh", "http"], False)
+        assert len(deckies) == 3
+        for decky in deckies:
+            assert decky.services == ["ssh", "http"]
+
+    def test_archetype_services(self):
+        arch = get_archetype("deaddeck")
+        deckies = build_deckies(2, self._IPS[:2], None, False, archetype=arch)
+        assert len(deckies) == 2
+        for decky in deckies:
+            assert set(decky.services) == set(arch.services)
+            assert decky.archetype == "deaddeck"
+            assert decky.nmap_os == arch.nmap_os
+
+    def test_randomize_services(self):
+        deckies = build_deckies(3, self._IPS, None, True)
+        assert len(deckies) == 3
+        for decky in deckies:
+            assert len(decky.services) >= 1
+
+    def test_no_services_raises(self):
+        with pytest.raises(ValueError, match="Provide services_explicit"):
+            build_deckies(1, self._IPS[:1], None, False)
+
+    def test_names_sequential(self):
+        deckies = build_deckies(3, self._IPS, ["ssh"], False)
+        assert [d.name for d in deckies] == ["decky-01", "decky-02", "decky-03"]
+
+    def test_ips_assigned_correctly(self):
+        deckies = build_deckies(3, self._IPS, ["ssh"], False)
+        assert [d.ip for d in deckies] == self._IPS
+
+    def test_mutate_interval_propagated(self):
+        deckies = build_deckies(1, self._IPS[:1], ["ssh"], False, mutate_interval=15)
+        assert deckies[0].mutate_interval == 15
+
+    def test_distros_explicit(self):
+        deckies = build_deckies(2, self._IPS[:2], ["ssh"], False, distros_explicit=["rocky9"])
+        for decky in deckies:
+            assert decky.distro == "rocky9"
+
+    def test_randomize_distros(self):
+        deckies = build_deckies(2, self._IPS[:2], ["ssh"], False, randomize_distros=True)
+        from decnet.distros import all_distros
+        valid = set(all_distros().keys())
+        for decky in deckies:
+            assert decky.distro in valid
+
+
+# ── build_deckies_from_ini ────────────────────────────────────────────────────
+
+class TestBuildDeckiesFromIni:
+    _SUBNET: str = "192.168.1.0/24"
+    _GATEWAY: str = "192.168.1.1"
+    _HOST_IP: str = "192.168.1.2"
+
+    def _make_ini(self, deckies: list[DeckySpec], **kwargs) -> IniConfig:
+        defaults: dict = {
+            "interface": "eth0",
+            "subnet": None,
+            "gateway": None,
+            "mutate_interval": None,
+            "custom_services": [],
+        }
+        defaults.update(kwargs)
+        return IniConfig(deckies=deckies, **defaults)
+
+    def test_explicit_ip(self):
+        spec = DeckySpec(name="test-1", ip="192.168.1.50", services=["ssh"])
+        ini = self._make_ini([spec])
+        deckies = build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False)
+        assert len(deckies) == 1
+        assert deckies[0].ip == "192.168.1.50"
+
+    def test_auto_ip_allocation(self):
+        spec = DeckySpec(name="test-1", services=["ssh"])
+        ini = self._make_ini([spec])
+        deckies = build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False)
+        assert len(deckies) == 1
+        assert deckies[0].ip not in (self._GATEWAY, self._HOST_IP, "192.168.1.0", "192.168.1.255")
+
+    def test_archetype_services(self):
+        spec = DeckySpec(name="test-1", archetype="deaddeck")
+        ini = self._make_ini([spec])
+        deckies = build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False)
+        arch = get_archetype("deaddeck")
+        assert set(deckies[0].services) == set(arch.services)
+
+    def test_randomize_services(self):
+        spec = DeckySpec(name="test-1")
+        ini = self._make_ini([spec])
+        deckies = build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, True)
+        assert len(deckies[0].services) >= 1
+
+    def test_no_services_no_arch_no_randomize_raises(self):
+        spec = DeckySpec(name="test-1")
+        ini = self._make_ini([spec])
+        with pytest.raises(ValueError, match="has no services"):
+            build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False)
+
+    def test_unknown_service_raises(self):
+        spec = DeckySpec(name="test-1", services=["nonexistent_svc_xyz"])
+        ini = self._make_ini([spec])
+        with pytest.raises(ValueError, match="Unknown service"):
+            build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False)
+
+    def test_mutate_interval_from_cli(self):
+        spec = DeckySpec(name="test-1", services=["ssh"])
+        ini = self._make_ini([spec])
+        deckies = build_deckies_from_ini(
+            ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False, cli_mutate_interval=42
+        )
+        assert deckies[0].mutate_interval == 42
+
+    def test_mutate_interval_from_ini(self):
+        spec = DeckySpec(name="test-1", services=["ssh"])
+        ini = self._make_ini([spec], mutate_interval=99)
+        deckies = build_deckies_from_ini(
+            ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False, cli_mutate_interval=None
+        )
+        assert deckies[0].mutate_interval == 99
+
+    def test_nmap_os_from_spec(self):
+        spec = DeckySpec(name="test-1", services=["ssh"], nmap_os="windows")
+        ini = self._make_ini([spec])
+        deckies = build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False)
+        assert deckies[0].nmap_os == "windows"
+
+    def test_nmap_os_from_archetype(self):
+        spec = DeckySpec(name="test-1", archetype="deaddeck")
+        ini = self._make_ini([spec])
+        deckies = build_deckies_from_ini(ini, self._SUBNET, self._GATEWAY, self._HOST_IP, False)
+        assert deckies[0].nmap_os == "linux"