added fresnel zone

api/tests/test_vegetation_integration.py

@@ -97,7 +97,54 @@ def test_link_budget_includes_diffraction_loss(monkeypatch) -> None:
     assert isclose(result.total_loss_db, result.fspl_db + result.diffraction_db)
     assert result.fresnel_clear is False
     assert result.los_clear is False
+    assert result.fresnel_quality == "blocked"
     assert result.geometric_los is False
     assert result.fresnel_violations_count > 0
     assert result.geometric_obstructions_count > 0
     assert result.worst_obstruction is not None
+
+
+def test_link_viable_depends_on_margin_not_fresnel_quality(monkeypatch) -> None:
+    monkeypatch.setattr(link_service, "vegetation_loss_along", lambda *args, **kwargs: 0.0)
+
+    def fake_profile(points, *args, **kwargs):
+        midpoint = len(points) // 2
+        return SurfaceProfile(
+            distance_m=points[-1].distance_m,
+            samples=[
+                SurfaceSample(
+                    i=index,
+                    lat=point.lat,
+                    lon=point.lon,
+                    distance_m=point.distance_m,
+                    ground_m=20.0 if index == midpoint else 0.0,
+                    building_m=0,
+                    canopy_m=0,
+                    surface_m=20.0 if index == midpoint else 0.0,
+                )
+                for index, point in enumerate(points)
+            ],
+        )
+
+    monkeypatch.setattr(link_service, "surface_profile_from_points", fake_profile)
+    request = LinkBudgetRequest(
+        tx=LinkTx(lat=60.17, lon=24.94, height_agl=0, power_dbm=70, gain_dbi=8),
+        rx=LinkRx(
+            lat=60.25,
+            lon=25.10,
+            height_agl=0,
+            gain_dbi=2,
+            sensitivity_dbm=-120,
+        ),
+        frequency_mhz=433,
+        model="manual",
+        include_buildings=False,
+        include_vegetation=False,
+    )
+
+    result = link_service.link_budget(request)
+
+    assert result.fade_margin_db > 0
+    assert result.fresnel_quality == "blocked"
+    assert result.fresnel_clear is False
+    assert result.link_viable is True