pytests for empty right/left banks

centerline_width/preprocessing.py

@@ -74,11 +74,9 @@ def generatePolygon(left_bank_lst,
                     recursion_check=False):
     # Return a shapely polygon based on the position of the river bank points
     if len(right_bank_lst) == 0:
-        logger.critical("\nCRITICAL ERROR, right bank data is empty (or NaN)")
-        exit()
+        raise ValueError("CRITICAL ERROR, right bank data is empty (or NaN)")
     if len(left_bank_lst) == 0:
-        logger.critical("\nCRITICAL ERROR, left bank data is empty (or NaN)")
-        exit()
+        raise ValueError("\nCRITICAL ERROR, left bank data is empty (or NaN)")
     circular_list_of_banks = left_bank_lst + right_bank_lst[::-1] + [
         left_bank_lst[0]
     ]

centerline_width/pytests/test_verifyPreprocessing.py

@@ -0,0 +1,34 @@
+# centerline-width/: python -m pytest -v
+# Pytests to Compare and Verify Expected Outputs
+from io import StringIO
+import re
+
+# External Python libraries (installed via pip install)
+import pytest
+
+# Internal centerline-width reference to access functions, global variables, and error handling
+import centerline_width
+
+
+def test_preprocessing_emptyRightBankCSV():
+    with pytest.raises(
+            ValueError,
+            match=re.escape(
+                "CRITICAL ERROR, right bank data is empty (or NaN)")):
+        csv_example = StringIO()
+        csv_example.write("llat,llon,rlat,rlon\n")
+        csv_example.write("30.037581,-92.868569,,\n")
+        csv_example.seek(0)
+        centerline_width.riverCenterline(csv_data=csv_example)
+
+
+def test_preprocessing_emptyLeftBankCSV():
+    with pytest.raises(
+            ValueError,
+            match=re.escape(
+                "CRITICAL ERROR, left bank data is empty (or NaN)")):
+        csv_example = StringIO()
+        csv_example.write("llat,llon,rlat,rlon\n")
+        csv_example.write(",,30.037441,-92.867476\n")
+        csv_example.seek(0)
+        centerline_width.riverCenterline(csv_data=csv_example)

centerline_width/relativeDistance.py

@@ -23,11 +23,14 @@ def relativeSingleCoordinate(first_point, lat_lon_coord, ellipsoid):
 def relativeBankCoordinates(left_lon_lat_coordinates,
                             right_lon_lat_coordinates, ellipsoid):
     # Convert bank latitude/longtiude coordinates to relative coordinates
-    first_point = left_lon_lat_coordinates[
-        0]  # first point is the first point on the left bank
-
     if left_lon_lat_coordinates is None or right_lon_lat_coordinates is None:
         return None, None
+    if len(left_lon_lat_coordinates) == 0 or len(
+            right_lon_lat_coordinates) == 0:
+        return None, None
+
+    first_point = left_lon_lat_coordinates[
+        0]  # first point is the first point on the left bank
 
     left_relative_coordinates = []
     for left_point in left_lon_lat_coordinates: