traceparse: os dispatcher and trace completion detection

src/netcheck/traceparse.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import re
 
-from netcheck.models import TraceHop
+from netcheck.models import TraceHop, TraceResult
 from netcheck.stats import rtt_stats
 
 IPV4_RE = re.compile(r"\b(?:\d{1,3}\.){3}\d{1,3}\b")
@@ -147,3 +147,33 @@ def parse_darwin(text: str) -> list[TraceHop]:
             if token not in hop.annotations:
                 hop.annotations.append(token)
     return [finalize_hop(hop) for hop in hops]
+
+
+def parse_traceroute(text: str, os_name: str) -> list[TraceHop]:
+    if os_name == "Windows":
+        return parse_windows(text)
+    if os_name == "Darwin":
+        return parse_darwin(text)
+    return parse_linux(text)
+
+
+def build_trace_result(
+    text: str,
+    os_name: str,
+    target: str,
+    resolved_ip: str | None,
+    backend: str = "system_traceroute",
+    max_hops: int = 30,
+) -> TraceResult:
+    hops = parse_traceroute(text, os_name)
+    completed = bool(hops and resolved_ip and hops[-1].ip == resolved_ip)
+    max_hops_reached = bool(hops) and not completed and hops[-1].ttl >= max_hops
+    return TraceResult(
+        target=target,
+        resolved_ip=resolved_ip,
+        backend=backend,
+        hops=hops,
+        cycles=1,
+        completed=completed,
+        max_hops_reached=max_hops_reached,
+    )

tests/test_traceparse.py

@@ -183,3 +183,66 @@ def test_darwin_partial_timeout_hop_keeps_positions(trace_fixture):
 
 def test_darwin_parser_tolerates_empty_input():
     assert parse_darwin("") == []
+
+
+from netcheck.traceparse import build_trace_result, parse_traceroute
+
+
+def test_dispatcher_routes_by_os_name(trace_fixture):
+    win = parse_traceroute(trace_fixture("windows", "tracert_en.txt"), "Windows")
+    lin = parse_traceroute(trace_fixture("linux", "gnu_basic.txt"), "Linux")
+    mac = parse_traceroute(trace_fixture("darwin", "bsd_basic.txt"), "Darwin")
+    assert win[0].probes[1] == 0.5
+    assert lin[0].probes == [1.234, 1.102, 1.045]
+    assert mac[0].probes == [2.145, 1.902, 1.87]
+
+
+def test_dispatcher_defaults_unknown_os_to_the_gnu_parser(trace_fixture):
+    hops = parse_traceroute(trace_fixture("linux", "gnu_basic.txt"), "SunOS")
+    assert [h.ttl for h in hops] == [1, 2, 3, 4, 5, 6]
+
+
+def test_build_trace_result_marks_completion_when_the_target_is_reached(trace_fixture):
+    result = build_trace_result(
+        trace_fixture("linux", "gnu_basic.txt"),
+        "Linux",
+        target="1.1.1.1",
+        resolved_ip="1.1.1.1",
+        max_hops=30,
+    )
+    assert result.completed is True
+    assert result.max_hops_reached is False
+    assert result.backend == "system_traceroute"
+    assert result.cycles == 1
+    assert len(result.hops) == 6
+
+
+def test_build_trace_result_flags_a_run_that_died_at_max_hops(trace_fixture):
+    result = build_trace_result(
+        trace_fixture("linux", "gnu_maxhops.txt"),
+        "Linux",
+        target="203.0.113.200",
+        resolved_ip="203.0.113.200",
+        max_hops=5,
+    )
+    assert result.completed is False
+    assert result.max_hops_reached is True
+
+
+def test_build_trace_result_is_not_complete_when_the_last_hop_is_a_different_host(trace_fixture):
+    result = build_trace_result(
+        trace_fixture("linux", "gnu_unreachable.txt"),
+        "Linux",
+        target="203.0.113.9",
+        resolved_ip="203.0.113.9",
+        max_hops=30,
+    )
+    assert result.completed is False
+    assert result.max_hops_reached is False
+
+
+def test_build_trace_result_on_empty_output_is_a_well_formed_empty_result():
+    result = build_trace_result("", "Linux", target="1.1.1.1", resolved_ip=None)
+    assert result.hops == []
+    assert result.completed is False
+    assert result.max_hops_reached is False