feat: travel calculation (km, CO2, frais réels fiscaux)

tests/test_travel_calc.py

@@ -0,0 +1,57 @@
+from app.business.travel_calc import (
+    compute_km_for_entry,
+    compute_co2_grams,
+    compute_frais_reels,
+)
+
+VEHICLES = {
+    "voiture": {"co2_per_km": 142, "cv": 5},
+    "velo": {"co2_per_km": 0},
+}
+
+JOURNEYS = {
+    "voiture_seule": {"distances": {"voiture": 25}},
+    "voiture_velo": {"distances": {"voiture": 14, "velo": 8}},
+    "velo_seul": {"distances": {"velo": 24}},
+}
+
+TRANCHES_CV5 = [
+    {"km_max": 3000, "taux": 0.548, "forfait": 0},
+    {"km_max": 6000, "taux": 0.316, "forfait": 699},
+    {"km_max": 0,    "taux": 0.364, "forfait": 0},
+]
+
+
+def test_compute_km_voiture_seule():
+    assert compute_km_for_entry("voiture_seule", JOURNEYS) == {"voiture": 25}
+
+
+def test_compute_km_voiture_velo():
+    assert compute_km_for_entry("voiture_velo", JOURNEYS) == {"voiture": 14, "velo": 8}
+
+
+def test_compute_km_no_journey():
+    assert compute_km_for_entry(None, JOURNEYS) == {}
+
+
+def test_compute_co2_voiture():
+    assert compute_co2_grams({"voiture": 25}, VEHICLES) == 25 * 142
+
+
+def test_compute_co2_velo():
+    assert compute_co2_grams({"velo": 24}, VEHICLES) == 0
+
+
+def test_frais_reels_tranche1():
+    result = compute_frais_reels(2000, TRANCHES_CV5)
+    assert abs(result - 1096.0) < 0.01
+
+
+def test_frais_reels_tranche2():
+    result = compute_frais_reels(4000, TRANCHES_CV5)
+    assert abs(result - 1963.0) < 0.01
+
+
+def test_frais_reels_tranche3():
+    result = compute_frais_reels(7000, TRANCHES_CV5)
+    assert abs(result - 2548.0) < 0.01