added covarage

api/app/core/antenna.py

@@ -14,6 +14,7 @@ class AntennaPattern:
     beamwidth_v: float | None = None
     front_to_back_db: float = 25.0
     sidelobe_floor_db: float = -30.0
+    pattern_file: str | None = None
 
 
 def _angular_delta(angle: float, center: float) -> float:
@@ -34,7 +35,9 @@ def gain(pattern: AntennaPattern, az_deg: float, el_deg: float) -> float:
     if pattern.pattern == "omni":
         return pattern.gain_dbi
     if pattern.pattern == "file":
-        raise NotImplementedError("Antenna pattern file parsing is implemented in a later stage")
+        from app.core.antenna_pattern_file import gain_from_file
+
+        return gain_from_file(pattern, az_deg, el_deg)
     if pattern.pattern != "sector":
         raise ValueError(f"Unknown antenna pattern: {pattern.pattern}")