@mytec: feat: Phase 3.0 Architecture Refactor ✅

Major refactoring of RFCP backend:
- Modular propagation models (8 models)
- SharedMemoryManager for terrain data
- ProcessPoolExecutor parallel processing
- WebSocket progress streaming
- Building filtering pipeline (351k → 15k)
- 82 unit tests

Performance: Standard preset 38s → 5s (7.6x speedup)

Known issue: Detailed preset timeout (fix in 3.1.0)

backend/tests/test_geometry/test_diffraction.py

@@ -0,0 +1,60 @@
+"""
+Unit tests for knife-edge diffraction calculations.
+"""
+
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.geometry.diffraction import knife_edge_loss
+
+
+def freq_to_wl(freq_mhz):
+    return 300.0 / freq_mhz
+
+
+class TestKnifeEdgeLoss:
+    def test_no_obstruction_low_loss(self):
+        """Negative h means clearance above LOS — loss should be small."""
+        loss = knife_edge_loss(d1_m=500, d2_m=500, h_m=-10, wavelength_m=freq_to_wl(1800))
+        assert loss >= 0
+        assert loss < 3
+
+    def test_grazing_obstruction(self):
+        """h=0 means exactly at LOS line — ~6 dB loss."""
+        loss = knife_edge_loss(d1_m=500, d2_m=500, h_m=0, wavelength_m=freq_to_wl(1800))
+        assert 5 < loss < 8
+
+    def test_obstruction_increases_loss(self):
+        wl = freq_to_wl(1800)
+        loss_low = knife_edge_loss(d1_m=500, d2_m=500, h_m=1, wavelength_m=wl)
+        loss_high = knife_edge_loss(d1_m=500, d2_m=500, h_m=10, wavelength_m=wl)
+        assert loss_high > loss_low
+
+    def test_higher_freq_more_loss(self):
+        """Higher frequency = shorter wavelength = more diffraction loss."""
+        loss_low_f = knife_edge_loss(d1_m=500, d2_m=500, h_m=5, wavelength_m=freq_to_wl(450))
+        loss_high_f = knife_edge_loss(d1_m=500, d2_m=500, h_m=5, wavelength_m=freq_to_wl(1800))
+        assert loss_high_f > loss_low_f
+
+    def test_zero_distance_safe(self):
+        """Should not crash on zero distances."""
+        loss = knife_edge_loss(d1_m=0, d2_m=500, h_m=5, wavelength_m=freq_to_wl(900))
+        assert loss >= 0
+
+    def test_large_clearance(self):
+        """Very deep clearance (large negative h) should have near-zero loss."""
+        loss = knife_edge_loss(d1_m=500, d2_m=500, h_m=-50, wavelength_m=freq_to_wl(900))
+        assert loss < 1.0
+
+
+if __name__ == "__main__":
+    instance = TestKnifeEdgeLoss()
+    for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+        try:
+            getattr(instance, method_name)()
+            print(f"  PASS  {method_name}")
+        except Exception as e:
+            print(f"  FAIL  {method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_geometry/test_haversine.py

@@ -0,0 +1,74 @@
+"""
+Unit tests for haversine distance calculations.
+"""
+
+import sys
+import os
+import numpy as np
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.geometry.haversine import haversine_distance, haversine_batch, points_to_local_coords
+
+
+class TestHaversineDistance:
+    def test_same_point_is_zero(self):
+        d = haversine_distance(50.45, 30.52, 50.45, 30.52)
+        assert abs(d) < 1.0
+
+    def test_known_distance(self):
+        # Kyiv to Kharkiv ≈ 410 km
+        d = haversine_distance(50.45, 30.52, 49.99, 36.23)
+        assert 400000 < d < 420000
+
+    def test_short_distance(self):
+        # ~111m for 0.001 degree lat
+        d = haversine_distance(50.0, 30.0, 50.001, 30.0)
+        assert 100 < d < 120
+
+
+class TestHaversineBatch:
+    def test_single_point(self):
+        lats = np.array([50.001])
+        lons = np.array([30.0])
+        distances = haversine_batch(50.0, 30.0, lats, lons)
+        assert len(distances) == 1
+        assert 100 < distances[0] < 120
+
+    def test_multiple_points(self):
+        lats = np.array([50.001, 50.01, 50.1])
+        lons = np.array([30.0, 30.0, 30.0])
+        distances = haversine_batch(50.0, 30.0, lats, lons)
+        assert len(distances) == 3
+        # Should be monotonically increasing
+        assert distances[0] < distances[1] < distances[2]
+
+
+class TestLocalCoords:
+    def test_same_point_is_origin(self):
+        x, y = points_to_local_coords(50.0, 30.0, np.array([50.0]), np.array([30.0]))
+        assert abs(x[0]) < 1.0
+        assert abs(y[0]) < 1.0
+
+    def test_north_is_positive_y(self):
+        x, y = points_to_local_coords(50.0, 30.0, np.array([50.001]), np.array([30.0]))
+        assert y[0] > 0
+        assert abs(x[0]) < 1.0
+
+    def test_east_is_positive_x(self):
+        x, y = points_to_local_coords(50.0, 30.0, np.array([50.0]), np.array([30.001]))
+        assert x[0] > 0
+        assert abs(y[0]) < 1.0
+
+
+if __name__ == "__main__":
+    for cls in [TestHaversineDistance, TestHaversineBatch, TestLocalCoords]:
+        instance = cls()
+        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls.__name__}.{method_name}")
+            except Exception as e:
+                print(f"  FAIL  {cls.__name__}.{method_name}: {e}")
+
+    print("\nAll tests completed.")

backend/tests/test_geometry/test_intersection.py

@@ -0,0 +1,77 @@
+"""
+Unit tests for line-segment intersection calculations.
+
+These require NumPy, so use __main__ block with conditional import.
+"""
+
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+import numpy as np
+from app.geometry.intersection import line_segments_intersect_batch
+
+
+class TestLineSegmentIntersect:
+    def test_crossing_lines(self):
+        """Two crossing segments should intersect."""
+        # Line from (0,0)→(1,1) and (0,1)→(1,0)
+        result = line_segments_intersect_batch(
+            p1=np.array([0.0, 0.0]),
+            p2=np.array([1.0, 1.0]),
+            seg_starts=np.array([[0.0, 1.0]]),
+            seg_ends=np.array([[1.0, 0.0]]),
+        )
+        assert result[0] == True
+
+    def test_parallel_lines(self):
+        """Parallel lines should not intersect."""
+        result = line_segments_intersect_batch(
+            p1=np.array([0.0, 0.0]),
+            p2=np.array([1.0, 0.0]),
+            seg_starts=np.array([[0.0, 1.0]]),
+            seg_ends=np.array([[1.0, 1.0]]),
+        )
+        assert result[0] == False
+
+    def test_non_crossing(self):
+        """Segments that don't reach each other."""
+        result = line_segments_intersect_batch(
+            p1=np.array([0.0, 0.0]),
+            p2=np.array([0.5, 0.5]),
+            seg_starts=np.array([[0.8, 0.0]]),
+            seg_ends=np.array([[0.8, 1.0]]),
+        )
+        assert result[0] == False
+
+    def test_multiple_segments(self):
+        """Batch test with multiple segments."""
+        result = line_segments_intersect_batch(
+            p1=np.array([0.0, 0.0]),
+            p2=np.array([1.0, 1.0]),
+            seg_starts=np.array([
+                [0.0, 1.0],   # crosses
+                [2.0, 0.0],   # doesn't cross
+                [0.5, 0.0],   # crosses
+            ]),
+            seg_ends=np.array([
+                [1.0, 0.0],   # crosses
+                [2.0, 1.0],   # doesn't cross
+                [0.5, 1.0],   # crosses
+            ]),
+        )
+        assert result[0] == True
+        assert result[1] == False
+        assert result[2] == True
+
+
+if __name__ == "__main__":
+    instance = TestLineSegmentIntersect()
+    for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+        try:
+            getattr(instance, method_name)()
+            print(f"  PASS  {method_name}")
+        except Exception as e:
+            print(f"  FAIL  {method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_geometry/test_los.py

@@ -0,0 +1,103 @@
+"""
+Unit tests for line-of-sight and Fresnel zone calculations.
+"""
+
+import sys
+import os
+import math
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.geometry.los import fresnel_radius, check_los_terrain
+
+
+def freq_to_wavelength(freq_mhz):
+    return 300.0 / freq_mhz
+
+
+class TestFresnelRadius:
+    def test_positive_result(self):
+        r = fresnel_radius(500, 500, freq_to_wavelength(1800))
+        assert r > 0
+
+    def test_symmetric(self):
+        wl = freq_to_wavelength(900)
+        r1 = fresnel_radius(300, 700, wl)
+        r2 = fresnel_radius(700, 300, wl)
+        assert abs(r1 - r2) < 0.001
+
+    def test_lower_freq_larger_radius(self):
+        r_high = fresnel_radius(500, 500, freq_to_wavelength(1800))
+        r_low = fresnel_radius(500, 500, freq_to_wavelength(900))
+        assert r_low > r_high
+
+    def test_center_is_maximum(self):
+        """Fresnel radius is largest at the midpoint of the path."""
+        wl = freq_to_wavelength(900)
+        r_center = fresnel_radius(500, 500, wl)
+        r_offset = fresnel_radius(200, 800, wl)
+        assert r_center > r_offset
+
+    def test_known_value(self):
+        """First Fresnel zone radius at midpoint of 1km path at 1GHz ~ 8.66m."""
+        # F1 = sqrt(lambda * d1 * d2 / (d1+d2))
+        # lambda = 0.3m at 1000MHz, d1=d2=500m
+        # F1 = sqrt(0.3 * 500 * 500 / 1000) = sqrt(75) ~ 8.66m
+        r = fresnel_radius(500, 500, freq_to_wavelength(1000))
+        assert 8.0 < r < 9.5
+
+    def test_zero_distance(self):
+        r = fresnel_radius(0, 500, freq_to_wavelength(900))
+        assert r == 0.0
+
+
+class TestCheckLosTerrain:
+    def test_flat_terrain_has_los(self):
+        profile = [
+            {"elevation": 100, "distance": 0},
+            {"elevation": 100, "distance": 250},
+            {"elevation": 100, "distance": 500},
+            {"elevation": 100, "distance": 750},
+            {"elevation": 100, "distance": 1000},
+        ]
+        result = check_los_terrain(profile, tx_height=30, rx_height=1.5)
+        assert result["has_los"] is True
+        assert result["clearance"] > 0
+
+    def test_hill_blocks_los(self):
+        profile = [
+            {"elevation": 100, "distance": 0},
+            {"elevation": 100, "distance": 250},
+            {"elevation": 200, "distance": 500},  # 100m hill
+            {"elevation": 100, "distance": 750},
+            {"elevation": 100, "distance": 1000},
+        ]
+        result = check_los_terrain(profile, tx_height=10, rx_height=1.5)
+        assert result["has_los"] is False
+        assert result["blocked_at"] is not None
+
+    def test_empty_profile(self):
+        result = check_los_terrain([], tx_height=30, rx_height=1.5)
+        assert result["has_los"] is True
+
+    def test_high_antenna_clears_hill(self):
+        profile = [
+            {"elevation": 100, "distance": 0},
+            {"elevation": 110, "distance": 500},
+            {"elevation": 100, "distance": 1000},
+        ]
+        # TX at 150m (100+50), RX at 101.5m. LOS at 500m ≈ 125.75m, terrain=110m → clear
+        result = check_los_terrain(profile, tx_height=50, rx_height=1.5)
+        assert result["has_los"] is True
+
+
+if __name__ == "__main__":
+    for cls in [TestFresnelRadius, TestCheckLosTerrain]:
+        instance = cls()
+        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls.__name__}.{method_name}")
+            except Exception as e:
+                print(f"  FAIL  {cls.__name__}.{method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_integration/__init__.py

@@ -0,0 +1 @@
+

backend/tests/test_integration/test_calculator.py

@@ -0,0 +1,127 @@
+"""
+Integration tests for the PointCalculator.
+
+Verifies end-to-end point calculation with various
+propagation models and environmental conditions.
+"""
+
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.core.calculator import PointCalculator
+from app.propagation.free_space import FreeSpaceModel
+from app.propagation.okumura_hata import OkumuraHataModel
+from app.propagation.cost231_hata import Cost231HataModel
+
+
+class TestPointCalculatorFSPL:
+    def test_basic_calculation(self):
+        calc = PointCalculator(FreeSpaceModel())
+        result = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.001, point_lon=30.0,
+            distance=111,
+        )
+        assert result.rsrp > -50  # Strong signal at short range
+        assert result.has_los is True
+        assert result.model_used == "Free-Space"
+        assert result.path_loss > 0
+        assert result.terrain_loss == 0
+        assert result.building_loss == 0
+
+    def test_signal_decreases_with_distance(self):
+        calc = PointCalculator(FreeSpaceModel())
+        near = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.001, point_lon=30.0, distance=100,
+        )
+        far = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.01, point_lon=30.0, distance=1000,
+        )
+        assert near.rsrp > far.rsrp
+
+    def test_terrain_obstruction(self):
+        calc = PointCalculator(FreeSpaceModel())
+        los = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.01, point_lon=30.0, distance=1000,
+        )
+        nlos = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.01, point_lon=30.0, distance=1000,
+            terrain_clearance=-10,
+        )
+        assert nlos.rsrp < los.rsrp
+        assert nlos.has_los is False
+        assert nlos.terrain_loss > 0
+
+    def test_building_loss_applied(self):
+        calc = PointCalculator(FreeSpaceModel())
+        no_building = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.01, point_lon=30.0, distance=1000,
+        )
+        with_building = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.01, point_lon=30.0, distance=1000,
+            building_loss=20,
+        )
+        assert abs(no_building.rsrp - with_building.rsrp - 20) < 0.1
+
+
+class TestPointCalculatorAntenna:
+    def test_off_axis_reduces_signal(self):
+        calc = PointCalculator(FreeSpaceModel())
+        omni = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.001, point_lon=30.0, distance=111,
+        )
+        directional = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=1800,
+            point_lat=50.001, point_lon=30.0, distance=111,
+            azimuth=90, beamwidth=65,  # Pointing East, point is North
+        )
+        assert directional.rsrp < omni.rsrp
+
+
+class TestPointCalculatorModelFallback:
+    def test_out_of_range_uses_fspl(self):
+        """When Okumura-Hata is out of valid range, should fall back to FSPL."""
+        calc = PointCalculator(OkumuraHataModel())
+        # 50m distance is below Okumura-Hata minimum (1km)
+        result = calc.calculate_point(
+            site_lat=50.0, site_lon=30.0, site_height=30,
+            site_power=43, site_gain=18, site_frequency=900,
+            point_lat=50.0, point_lon=30.0001, distance=50,
+        )
+        # Should still return a valid result (via FSPL fallback)
+        assert result.rsrp != 0
+        assert result.path_loss > 0
+
+
+if __name__ == "__main__":
+    for cls_name, cls in [
+        ("FSPL", TestPointCalculatorFSPL),
+        ("Antenna", TestPointCalculatorAntenna),
+        ("Fallback", TestPointCalculatorModelFallback),
+    ]:
+        instance = cls()
+        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls_name}.{method_name}")
+            except Exception as e:
+                print(f"  FAIL  {cls_name}.{method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_integration/test_engine.py

@@ -0,0 +1,115 @@
+"""
+Integration tests for the CoverageEngine orchestrator.
+
+Tests model selection, available models API, and the
+engine's coordination logic (without running actual
+coverage calculations, which require terrain data).
+"""
+
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.core.engine import CoverageEngine, BandType, PresetType, CoverageSettings
+
+
+class TestEngineModelSelection:
+    def test_lte_urban_uses_cost231(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.LTE, "urban")
+        assert model.name == "COST-231-Hata"
+
+    def test_lte_suburban_uses_okumura(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.LTE, "suburban")
+        assert model.name == "Okumura-Hata"
+
+    def test_lte_open_uses_fspl(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.LTE, "open")
+        assert model.name == "Free-Space"
+
+    def test_uhf_urban_uses_okumura(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.UHF, "urban")
+        assert model.name == "Okumura-Hata"
+
+    def test_uhf_rural_uses_longley_rice(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.UHF, "rural")
+        assert model.name == "Longley-Rice"
+
+    def test_vhf_urban_uses_p1546(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.VHF, "urban")
+        assert model.name == "ITU-R-P.1546"
+
+    def test_vhf_rural_uses_longley_rice(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.VHF, "rural")
+        assert model.name == "Longley-Rice"
+
+    def test_unknown_band_falls_back(self):
+        engine = CoverageEngine()
+        model = engine.select_model(BandType.CUSTOM, "desert")
+        assert model is not None  # Should not crash
+
+
+class TestEngineModelsAPI:
+    def test_returns_dict(self):
+        engine = CoverageEngine()
+        models = engine.get_available_models()
+        assert isinstance(models, dict)
+        assert len(models) >= 5
+
+    def test_model_info_structure(self):
+        engine = CoverageEngine()
+        models = engine.get_available_models()
+        for name, info in models.items():
+            assert "frequency_range" in info
+            assert "distance_range" in info
+            assert "bands" in info
+            assert len(info["bands"]) > 0
+
+    def test_all_expected_models_present(self):
+        engine = CoverageEngine()
+        models = engine.get_available_models()
+        expected = {"COST-231-Hata", "Okumura-Hata", "Free-Space", "Longley-Rice", "ITU-R-P.1546"}
+        assert expected.issubset(set(models.keys()))
+
+
+class TestCoverageSettings:
+    def test_default_settings(self):
+        s = CoverageSettings()
+        assert s.radius == 10000
+        assert s.resolution == 200
+        assert s.preset == PresetType.STANDARD
+        assert s.band_type == BandType.LTE
+
+    def test_preset_values(self):
+        assert PresetType.FAST.value == "fast"
+        assert PresetType.STANDARD.value == "standard"
+        assert PresetType.DETAILED.value == "detailed"
+        assert PresetType.FULL.value == "full"
+
+    def test_band_type_values(self):
+        assert BandType.LTE.value == "lte"
+        assert BandType.UHF.value == "uhf"
+        assert BandType.VHF.value == "vhf"
+
+
+if __name__ == "__main__":
+    for cls_name, cls in [
+        ("ModelSelection", TestEngineModelSelection),
+        ("ModelsAPI", TestEngineModelsAPI),
+        ("CoverageSettings", TestCoverageSettings),
+    ]:
+        instance = cls()
+        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls_name}.{method_name}")
+            except Exception as e:
+                print(f"  FAIL  {cls_name}.{method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_models/test_cost231.py

@@ -0,0 +1,90 @@
+"""
+Unit tests for COST-231 Hata and COST-231 Walfisch-Ikegami models.
+"""
+
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.propagation.base import PropagationInput
+from app.propagation.cost231_hata import Cost231HataModel
+from app.propagation.cost231_wi import Cost231WIModel
+
+
+def make_input(**kwargs) -> PropagationInput:
+    defaults = {
+        "frequency_mhz": 1800,
+        "distance_m": 5000,
+        "tx_height_m": 30,
+        "rx_height_m": 1.5,
+        "environment": "urban",
+    }
+    defaults.update(kwargs)
+    return PropagationInput(**defaults)
+
+
+class TestCost231Hata:
+    def test_typical_range(self):
+        model = Cost231HataModel()
+        out = model.calculate(make_input())
+        assert 130 < out.path_loss_db < 170
+
+    def test_model_name(self):
+        model = Cost231HataModel()
+        assert model.name == "COST-231-Hata"
+
+    def test_frequency_range(self):
+        model = Cost231HataModel()
+        assert model.is_valid_for(make_input(frequency_mhz=1500))
+        assert model.is_valid_for(make_input(frequency_mhz=2000))
+        assert not model.is_valid_for(make_input(frequency_mhz=900))
+
+    def test_distance_increases_loss(self):
+        model = Cost231HataModel()
+        loss_2 = model.calculate(make_input(distance_m=2000)).path_loss_db
+        loss_10 = model.calculate(make_input(distance_m=10000)).path_loss_db
+        assert loss_10 > loss_2
+
+    def test_urban_vs_suburban(self):
+        model = Cost231HataModel()
+        urban = model.calculate(make_input(environment="urban")).path_loss_db
+        suburban = model.calculate(make_input(environment="suburban")).path_loss_db
+        assert suburban < urban
+
+
+class TestCost231WI:
+    def test_typical_range(self):
+        model = Cost231WIModel()
+        out = model.calculate(make_input(distance_m=500))
+        assert 80 < out.path_loss_db < 160
+
+    def test_model_name(self):
+        model = Cost231WIModel()
+        assert model.name == "COST-231-WI"
+
+    def test_distance_increases_loss(self):
+        model = Cost231WIModel()
+        loss_200 = model.calculate(make_input(distance_m=200)).path_loss_db
+        loss_1000 = model.calculate(make_input(distance_m=1000)).path_loss_db
+        assert loss_1000 > loss_200
+
+    def test_frequency_range(self):
+        model = Cost231WIModel()
+        assert model.is_valid_for(make_input(frequency_mhz=800))
+        assert model.is_valid_for(make_input(frequency_mhz=2000))
+        assert not model.is_valid_for(make_input(frequency_mhz=400))
+
+
+if __name__ == "__main__":
+    for cls_name, cls in [("COST231Hata", TestCost231Hata), ("COST231WI", TestCost231WI)]:
+        instance = cls()
+        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls_name}.{method_name}")
+            except AssertionError as e:
+                print(f"  FAIL  {cls_name}.{method_name}: {e}")
+            except Exception as e:
+                print(f"  ERROR {cls_name}.{method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_models/test_free_space.py

@@ -0,0 +1,82 @@
+"""
+Detailed unit tests for the Free Space Path Loss model.
+"""
+
+import sys
+import os
+import math
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.propagation.base import PropagationInput
+from app.propagation.free_space import FreeSpaceModel
+
+
+def make_input(**kwargs) -> PropagationInput:
+    defaults = {
+        "frequency_mhz": 1800,
+        "distance_m": 1000,
+        "tx_height_m": 30,
+        "rx_height_m": 1.5,
+        "environment": "urban",
+    }
+    defaults.update(kwargs)
+    return PropagationInput(**defaults)
+
+
+class TestFreeSpaceModel:
+    def test_formula_accuracy(self):
+        """FSPL = 20*log10(d_km) + 20*log10(f_MHz) + 32.45"""
+        model = FreeSpaceModel()
+        # At 1km, 1000MHz: 20*0 + 20*60 + 32.45 = 92.45 dB
+        out = model.calculate(make_input(distance_m=1000, frequency_mhz=1000))
+        expected = 32.45 + 20 * math.log10(1.0) + 20 * math.log10(1000)
+        assert abs(out.path_loss_db - expected) < 0.1
+
+    def test_6db_per_distance_doubling(self):
+        model = FreeSpaceModel()
+        loss_1 = model.calculate(make_input(distance_m=1000)).path_loss_db
+        loss_2 = model.calculate(make_input(distance_m=2000)).path_loss_db
+        assert abs((loss_2 - loss_1) - 6.02) < 0.1
+
+    def test_6db_per_frequency_doubling(self):
+        model = FreeSpaceModel()
+        loss_1 = model.calculate(make_input(frequency_mhz=900)).path_loss_db
+        loss_2 = model.calculate(make_input(frequency_mhz=1800)).path_loss_db
+        assert abs((loss_2 - loss_1) - 6.02) < 0.1
+
+    def test_always_los(self):
+        model = FreeSpaceModel()
+        out = model.calculate(make_input())
+        assert out.is_los is True
+
+    def test_model_name(self):
+        model = FreeSpaceModel()
+        assert model.name == "Free-Space"
+
+    def test_wide_frequency_range(self):
+        model = FreeSpaceModel()
+        assert model.is_valid_for(make_input(frequency_mhz=1))
+        assert model.is_valid_for(make_input(frequency_mhz=100000))
+
+    def test_very_short_distance(self):
+        model = FreeSpaceModel()
+        out = model.calculate(make_input(distance_m=10))
+        assert out.path_loss_db > 0
+        assert out.path_loss_db < 80
+
+    def test_very_long_distance(self):
+        model = FreeSpaceModel()
+        out = model.calculate(make_input(distance_m=100000))
+        assert out.path_loss_db > 120
+
+
+if __name__ == "__main__":
+    instance = TestFreeSpaceModel()
+    for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+        try:
+            getattr(instance, method_name)()
+            print(f"  PASS  {method_name}")
+        except Exception as e:
+            print(f"  FAIL  {method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_models/test_okumura_hata.py

@@ -0,0 +1,93 @@
+"""
+Detailed unit tests for the Okumura-Hata model.
+"""
+
+import sys
+import os
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.propagation.base import PropagationInput
+from app.propagation.okumura_hata import OkumuraHataModel
+
+
+def make_input(**kwargs) -> PropagationInput:
+    defaults = {
+        "frequency_mhz": 900,
+        "distance_m": 5000,
+        "tx_height_m": 30,
+        "rx_height_m": 1.5,
+        "environment": "urban",
+    }
+    defaults.update(kwargs)
+    return PropagationInput(**defaults)
+
+
+class TestOkumuraHata:
+    def test_urban_typical_range(self):
+        model = OkumuraHataModel()
+        out = model.calculate(make_input())
+        # 900MHz, 5km, urban: expect ~130-155 dB
+        assert 120 < out.path_loss_db < 160
+
+    def test_environment_ordering(self):
+        """Urban > suburban > rural path loss."""
+        model = OkumuraHataModel()
+        urban = model.calculate(make_input(environment="urban")).path_loss_db
+        suburban = model.calculate(make_input(environment="suburban")).path_loss_db
+        rural = model.calculate(make_input(environment="rural")).path_loss_db
+        assert urban > suburban > rural
+
+    def test_distance_increases_loss(self):
+        model = OkumuraHataModel()
+        loss_1 = model.calculate(make_input(distance_m=2000)).path_loss_db
+        loss_5 = model.calculate(make_input(distance_m=5000)).path_loss_db
+        loss_10 = model.calculate(make_input(distance_m=10000)).path_loss_db
+        assert loss_1 < loss_5 < loss_10
+
+    def test_frequency_increases_loss(self):
+        model = OkumuraHataModel()
+        loss_450 = model.calculate(make_input(frequency_mhz=450)).path_loss_db
+        loss_900 = model.calculate(make_input(frequency_mhz=900)).path_loss_db
+        assert loss_900 > loss_450
+
+    def test_higher_tx_reduces_loss(self):
+        model = OkumuraHataModel()
+        loss_low = model.calculate(make_input(tx_height_m=10)).path_loss_db
+        loss_high = model.calculate(make_input(tx_height_m=50)).path_loss_db
+        assert loss_high < loss_low
+
+    def test_valid_frequency_range(self):
+        model = OkumuraHataModel()
+        assert model.is_valid_for(make_input(frequency_mhz=150))
+        assert model.is_valid_for(make_input(frequency_mhz=1500))
+        assert not model.is_valid_for(make_input(frequency_mhz=2000))
+
+    def test_valid_distance_range(self):
+        model = OkumuraHataModel()
+        assert model.is_valid_for(make_input(distance_m=500))
+        assert model.is_valid_for(make_input(distance_m=20000))
+        # Out of range
+        assert not model.is_valid_for(make_input(distance_m=50))
+
+    def test_model_name(self):
+        model = OkumuraHataModel()
+        assert model.name == "Okumura-Hata"
+
+    def test_open_environment(self):
+        """Open environment should have even less loss than rural."""
+        model = OkumuraHataModel()
+        rural = model.calculate(make_input(environment="rural")).path_loss_db
+        open_area = model.calculate(make_input(environment="open")).path_loss_db
+        assert open_area < rural
+
+
+if __name__ == "__main__":
+    instance = TestOkumuraHata()
+    for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+        try:
+            getattr(instance, method_name)()
+            print(f"  PASS  {method_name}")
+        except Exception as e:
+            print(f"  FAIL  {method_name}: {e}")
+    print("\nAll tests completed.")

backend/tests/test_models/test_propagation.py

@@ -0,0 +1,198 @@
+"""
+Unit tests for propagation models.
+
+Run: cd backend && python -m pytest tests/test_models/test_propagation.py -v
+"""
+
+import math
+import sys
+import os
+
+# Add backend to path
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.propagation.base import PropagationInput
+from app.propagation.free_space import FreeSpaceModel
+from app.propagation.okumura_hata import OkumuraHataModel
+from app.propagation.cost231_hata import Cost231HataModel
+from app.propagation.cost231_wi import Cost231WIModel
+from app.propagation.itu_r_p1546 import ITUR_P1546Model
+from app.propagation.longley_rice import LongleyRiceModel
+from app.propagation.itu_r_p526 import KnifeEdgeDiffractionModel
+
+
+def make_input(**kwargs) -> PropagationInput:
+    defaults = {
+        "frequency_mhz": 1800,
+        "distance_m": 1000,
+        "tx_height_m": 30,
+        "rx_height_m": 1.5,
+        "environment": "urban",
+    }
+    defaults.update(kwargs)
+    return PropagationInput(**defaults)
+
+
+class TestFreeSpaceModel:
+    def test_basic_fspl(self):
+        model = FreeSpaceModel()
+        output = model.calculate(make_input(distance_m=1000, frequency_mhz=1800))
+        # FSPL at 1km, 1800MHz ≈ 97.5 dB
+        assert 95 < output.path_loss_db < 100
+        assert output.is_los is True
+        assert output.model_name == "Free-Space"
+
+    def test_distance_increases_loss(self):
+        model = FreeSpaceModel()
+        loss_1km = model.calculate(make_input(distance_m=1000)).path_loss_db
+        loss_2km = model.calculate(make_input(distance_m=2000)).path_loss_db
+        # Doubling distance adds ~6 dB
+        assert 5 < (loss_2km - loss_1km) < 7
+
+    def test_frequency_increases_loss(self):
+        model = FreeSpaceModel()
+        loss_900 = model.calculate(make_input(frequency_mhz=900)).path_loss_db
+        loss_1800 = model.calculate(make_input(frequency_mhz=1800)).path_loss_db
+        # Doubling frequency adds ~6 dB
+        assert 5 < (loss_1800 - loss_900) < 7
+
+    def test_valid_range(self):
+        model = FreeSpaceModel()
+        assert model.is_valid_for(make_input(distance_m=100))
+        assert model.is_valid_for(make_input(distance_m=100000))
+
+
+class TestOkumuraHata:
+    def test_urban_loss(self):
+        model = OkumuraHataModel()
+        output = model.calculate(make_input(
+            frequency_mhz=900, distance_m=5000,
+            tx_height_m=30, environment="urban",
+        ))
+        # Typical urban loss at 5km, 900MHz: 130-150 dB
+        assert 120 < output.path_loss_db < 160
+        assert output.model_name == "Okumura-Hata"
+
+    def test_suburban_less_than_urban(self):
+        model = OkumuraHataModel()
+        inp = make_input(frequency_mhz=900, distance_m=5000)
+        urban = model.calculate(PropagationInput(**{**inp.__dict__, "environment": "urban"}))
+        suburban = model.calculate(PropagationInput(**{**inp.__dict__, "environment": "suburban"}))
+        assert suburban.path_loss_db < urban.path_loss_db
+
+    def test_rural_less_than_suburban(self):
+        model = OkumuraHataModel()
+        inp = make_input(frequency_mhz=900, distance_m=5000)
+        suburban = model.calculate(PropagationInput(**{**inp.__dict__, "environment": "suburban"}))
+        rural = model.calculate(PropagationInput(**{**inp.__dict__, "environment": "rural"}))
+        assert rural.path_loss_db < suburban.path_loss_db
+
+    def test_valid_range(self):
+        model = OkumuraHataModel()
+        assert model.is_valid_for(make_input(frequency_mhz=900, distance_m=5000))
+        assert not model.is_valid_for(make_input(frequency_mhz=2000, distance_m=5000))
+
+
+class TestCost231Hata:
+    def test_basic_loss(self):
+        model = Cost231HataModel()
+        output = model.calculate(make_input(
+            frequency_mhz=1800, distance_m=5000,
+        ))
+        assert 130 < output.path_loss_db < 170
+        assert output.model_name == "COST-231-Hata"
+
+    def test_valid_range(self):
+        model = Cost231HataModel()
+        assert model.is_valid_for(make_input(frequency_mhz=1800, distance_m=5000))
+        assert not model.is_valid_for(make_input(frequency_mhz=900, distance_m=5000))
+
+
+class TestCost231WI:
+    def test_basic_loss(self):
+        model = Cost231WIModel()
+        output = model.calculate(make_input(
+            frequency_mhz=1800, distance_m=500,
+            environment="urban",
+        ))
+        assert 80 < output.path_loss_db < 160
+        assert output.model_name == "COST-231-WI"
+
+
+class TestITUR_P1546:
+    def test_basic_loss(self):
+        model = ITUR_P1546Model()
+        output = model.calculate(make_input(
+            frequency_mhz=450, distance_m=10000,
+        ))
+        assert 80 < output.path_loss_db < 160
+        assert output.model_name == "ITU-R-P.1546"
+
+
+class TestLongleyRice:
+    def test_basic_loss(self):
+        model = LongleyRiceModel()
+        output = model.calculate(make_input(
+            frequency_mhz=150, distance_m=20000,
+            terrain_roughness_m=50,
+        ))
+        assert 90 < output.path_loss_db < 160
+        assert output.model_name == "Longley-Rice"
+
+    def test_flat_terrain_is_los(self):
+        model = LongleyRiceModel()
+        output = model.calculate(make_input(
+            frequency_mhz=150, distance_m=5000,
+            terrain_roughness_m=5,
+        ))
+        assert output.is_los is True
+
+
+class TestKnifeEdgeDiffraction:
+    def test_no_obstruction(self):
+        loss = KnifeEdgeDiffractionModel.calculate_loss(
+            d1_m=500, d2_m=500, h_m=-5, wavelength_m=0.167,
+        )
+        assert loss >= 0
+
+    def test_obstruction_increases_loss(self):
+        loss_low = KnifeEdgeDiffractionModel.calculate_loss(
+            d1_m=500, d2_m=500, h_m=1, wavelength_m=0.167,
+        )
+        loss_high = KnifeEdgeDiffractionModel.calculate_loss(
+            d1_m=500, d2_m=500, h_m=10, wavelength_m=0.167,
+        )
+        assert loss_high > loss_low
+
+    def test_clearance_loss_positive_clearance(self):
+        loss = KnifeEdgeDiffractionModel.calculate_clearance_loss(5.0, 1800)
+        assert loss == 0.0
+
+    def test_clearance_loss_negative_clearance(self):
+        loss = KnifeEdgeDiffractionModel.calculate_clearance_loss(-10.0, 1800)
+        assert loss > 0
+
+
+if __name__ == "__main__":
+    # Quick run without pytest
+    for cls_name, cls in [
+        ("FreeSpace", TestFreeSpaceModel),
+        ("OkumuraHata", TestOkumuraHata),
+        ("COST231Hata", TestCost231Hata),
+        ("COST231WI", TestCost231WI),
+        ("ITU-R-P.1546", TestITUR_P1546),
+        ("LongleyRice", TestLongleyRice),
+        ("KnifeEdge", TestKnifeEdgeDiffraction),
+    ]:
+        instance = cls()
+        methods = [m for m in dir(instance) if m.startswith("test_")]
+        for method_name in methods:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls_name}.{method_name}")
+            except AssertionError as e:
+                print(f"  FAIL  {cls_name}.{method_name}: {e}")
+            except Exception as e:
+                print(f"  ERROR {cls_name}.{method_name}: {e}")
+
+    print("\nAll tests completed.")

backend/tests/test_services/__init__.py

@@ -0,0 +1 @@
+

backend/tests/test_services/test_cache.py

@@ -0,0 +1,126 @@
+"""
+Unit tests for the unified cache service.
+"""
+
+import sys
+import os
+import time
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.services.cache import MemoryCache, CacheManager
+
+
+class TestMemoryCache:
+    def test_get_miss(self):
+        cache = MemoryCache("test", max_entries=10)
+        assert cache.get("nonexistent") is None
+
+    def test_put_get(self):
+        cache = MemoryCache("test", max_entries=10)
+        cache.put("key1", "value1", size_bytes=100)
+        assert cache.get("key1") == "value1"
+
+    def test_overwrite(self):
+        cache = MemoryCache("test", max_entries=10)
+        cache.put("key1", "v1", size_bytes=100)
+        cache.put("key1", "v2", size_bytes=200)
+        assert cache.get("key1") == "v2"
+        assert cache.size == 1
+        assert cache.size_bytes == 200
+
+    def test_eviction_by_entries(self):
+        cache = MemoryCache("test", max_entries=3)
+        cache.put("a", 1)
+        cache.put("b", 2)
+        cache.put("c", 3)
+        assert cache.size == 3
+        cache.put("d", 4)  # Should evict 'a' (LRU)
+        assert cache.size == 3
+        assert cache.get("a") is None
+        assert cache.get("d") == 4
+
+    def test_eviction_by_size(self):
+        cache = MemoryCache("test", max_entries=100, max_size_bytes=300)
+        cache.put("a", 1, size_bytes=100)
+        cache.put("b", 2, size_bytes=100)
+        cache.put("c", 3, size_bytes=100)
+        assert cache.size_bytes == 300
+        cache.put("d", 4, size_bytes=100)  # Should evict 'a'
+        assert cache.size_bytes == 300
+        assert cache.get("a") is None
+
+    def test_lru_access_order(self):
+        cache = MemoryCache("test", max_entries=3)
+        cache.put("a", 1)
+        cache.put("b", 2)
+        cache.put("c", 3)
+        # Access 'a' to make it recently used
+        cache.get("a")
+        # Add 'd' — should evict 'b' (now LRU)
+        cache.put("d", 4)
+        assert cache.get("a") == 1  # Still there
+        assert cache.get("b") is None  # Evicted
+
+    def test_remove(self):
+        cache = MemoryCache("test", max_entries=10)
+        cache.put("key1", "val", size_bytes=50)
+        assert cache.remove("key1") is True
+        assert cache.get("key1") is None
+        assert cache.size_bytes == 0
+
+    def test_clear(self):
+        cache = MemoryCache("test", max_entries=10)
+        cache.put("a", 1, size_bytes=100)
+        cache.put("b", 2, size_bytes=100)
+        cache.clear()
+        assert cache.size == 0
+        assert cache.size_bytes == 0
+
+    def test_stats(self):
+        cache = MemoryCache("test", max_entries=10, max_size_bytes=1024)
+        cache.put("a", 1, size_bytes=100)
+        cache.get("a")  # hit
+        cache.get("b")  # miss
+        s = cache.stats()
+        assert s["name"] == "test"
+        assert s["entries"] == 1
+        assert s["hits"] == 1
+        assert s["misses"] == 1
+        assert s["hit_rate"] == 50.0
+
+
+class TestCacheManager:
+    def test_singleton_structure(self):
+        mgr = CacheManager()
+        assert mgr.terrain is not None
+        assert mgr.buildings is not None
+        assert mgr.spatial is not None
+        assert mgr.osm_disk is not None
+
+    def test_stats(self):
+        mgr = CacheManager()
+        s = mgr.stats()
+        assert "terrain" in s
+        assert "buildings" in s
+        assert "total_memory_mb" in s
+
+    def test_clear_all(self):
+        mgr = CacheManager()
+        mgr.terrain.put("test", "data", 100)
+        mgr.buildings.put("test", "data", 100)
+        mgr.clear_all()
+        assert mgr.terrain.size == 0
+        assert mgr.buildings.size == 0
+
+
+if __name__ == "__main__":
+    for cls_name, cls in [("MemoryCache", TestMemoryCache), ("CacheManager", TestCacheManager)]:
+        instance = cls()
+        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls_name}.{method_name}")
+            except Exception as e:
+                print(f"  FAIL  {cls_name}.{method_name}: {e}")
+    print("\nAll tests completed.")