Implement normalize_lat_lng()

3 files changed, 37 insertions, 2 deletions

diff --git a/iss/server.py b/iss/server.py
index f014d7f..5597baa 100644
--- a/iss/server.py
+++ b/iss/server.py
@@ -3,6 +3,7 @@ from fastapi.staticfiles import StaticFiles
 from fastapi.templating import Jinja2Templates
 
 from .predictions import Predictions
+from .utils import normalize_lat_lng
 
 app = FastAPI()
 
@@ -20,7 +21,8 @@ async def home(request: Request):
 
 
 @app.get("/passes/{lat}/{lng}")
-async def passes(request: Request, lat: float, lng: float):
+async def passes(request: Request, lat: str, lng: str):
+    lat, lng = normalize_lat_lng(lat, lng)
     preds = Predictions(lat, lng, altitude=0, days=5).get_grouped_predictions()
     return templates.TemplateResponse(
         "passes.html",
diff --git a/iss/tests/test_utils.py b/iss/tests/test_utils.py
index ee4971f..17dadf8 100644
--- a/iss/tests/test_utils.py
+++ b/iss/tests/test_utils.py
@@ -1,4 +1,6 @@
-from ..utils import deg_to_cardinal, seconds_to_minutes
+import pytest
+
+from ..utils import deg_to_cardinal, seconds_to_minutes, normalize_lat_lng
 
 
 def test_seconds_to_minutes():
@@ -14,6 +16,29 @@ def test_seconds_to_minutes():
         assert seconds_to_minutes(secs) == s
 
 
+def test_normalize_lat_lng():
+    cases = [
+        ("N12.345", "E67.890", 12.345, 67.890),
+        ("S12.345", "W67.890", -12.345, -67.890),
+        ("S11", "W22", -11, -22),
+        ("N0.987", "W0.123", 0.987, -0.123),
+        ("S88.765", "E177.654", -88.765, 177.654),
+    ]
+    for lat, lng, nlat, nlng in cases:
+        assert normalize_lat_lng(lat, lng) == (nlat, nlng)
+
+
+def test_fail_normalize_lat_lng():
+    failures = [
+        ("12", "E45"),
+        ("B12", "E45"),
+        ("12", "X45"),
+    ]
+    for lat, lng in failures:
+        with pytest.raises(Exception):
+            normalize_lat_lng(lat, lng)
+
+
 def test_deg_to_cardinal():
     cases = [
         (0, "N"),
diff --git a/iss/utils.py b/iss/utils.py
index 326d835..656d4e3 100644
--- a/iss/utils.py
+++ b/iss/utils.py
@@ -7,6 +7,14 @@ def seconds_to_minutes(secs):
     return f"{secs // 60}:{secs % 60:02}"
 
 
+def normalize_lat_lng(lat, lng):
+    if lat[0] not in "NS" or lng[0] not in "EW":
+        raise Exception("Lat/lng must be formatted as N12.345 and E67.890")
+    nlat = float(lat[1:]) * (-1 if lat[0] == "S" else 1)
+    nlng = float(lng[1:]) * (-1 if lng[0] == "W" else 1)
+    return nlat, nlng
+
+
 def deg_to_cardinal(deg):
     cardinals = [
         "N",