Add validate method for polar file #24

.gitignore

@@ -5,4 +5,5 @@ dist
 .tox
 coverage.xml
 .coverage*
-*_cache
+*_cache
+venv/

tests/polar_test.py

@@ -15,16 +15,33 @@
 # For detail about GNU see <http://www.gnu.org/licenses/>.
 import math
 import os
+import tempfile
 import unittest
 
 import weatherrouting
 
 
+def create_temp_file(content: str, test_instance=None) -> str:
+    temp_file = tempfile.NamedTemporaryFile(
+        mode="w", delete=False, suffix=".pol", encoding="utf-8"
+    )
+    temp_file.write(content)
+    temp_file.close()
+    if test_instance:
+        test_instance.addCleanup(os.remove, temp_file.name)
+    return temp_file.name
+
+
 class TestPolar(unittest.TestCase):
     def setUp(self):
         self.polar_obj = weatherrouting.Polar(
             os.path.join(os.path.dirname(__file__), "data/bavaria38.pol")
         )
+        self.valid_file_path = os.path.join(
+            os.path.dirname(__file__), "data/bavaria38.pol"
+        )
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            self.valid_polar_content_lines = f.readlines()
 
     def test_to_string(self):
         f = open(os.path.join(os.path.dirname(__file__), "data/bavaria38.pol"), "r")
@@ -65,3 +82,94 @@ def test_reaching(self):
         self.assertAlmostEqual(
             self.polar_obj.get_reaching(6.1)[1], 1.3962634015954636, delta=0.001
         )
+
+    # --- Tests for Polar.validate_file ---
+    def test_validate_valid_file(self):
+        # This should not raise an error for a known valid file
+        try:
+            weatherrouting.Polar.validate_file(self.valid_file_path)
+        except weatherrouting.PolarError as e:
+            self.fail(
+                f"validate_polar_file raised PolarError unexpectedly for a valid file: {e}"
+            )
+
+    def test_validate_empty_file(self):
+        temp_file_path = create_temp_file("", self)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "EMPTY_FILE"):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_wind_numeric(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("30", "a")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(
+            weatherrouting.PolarError, "WIND_SPEED_NOT_NUMERIC"
+        ):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_wind_incresing(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("50", "100")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(
+            weatherrouting.PolarError, "WIND_SPEEDS_NOT_INCREASING"
+        ):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_empty_line(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("\n", "\n\n")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "EMPTY_LINE"):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_column_count_mismatch(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("60", "60 70")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "COLUMN_COUNT_MISMATCH"):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_twa_out_of_range(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("100", "181")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "TWA_OUT_OF_RANGE"):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_twa_not_numeric(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("100", "a")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "TWA_NOT_NUMERIC"):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_empty_value(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("7.7", "-")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "EMPTY_VALUE"):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_negative_speed(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("7.7", "-1")
+        temp_file_path = create_temp_file(corrupt_content)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "NEGATIVE_SPEED"):
+            weatherrouting.Polar.validate_file(temp_file_path)
+
+    def test_validate_speed_not_numeric(self):
+        with open(self.valid_file_path, "r", encoding="utf-8") as f:
+            valid_content = f.read()
+        corrupt_content = valid_content.replace("7.7", "a")
+        temp_file_path = create_temp_file(corrupt_content, self)
+        with self.assertRaisesRegex(weatherrouting.PolarError, "SPEED_NOT_NUMERIC"):
+            weatherrouting.Polar.validate_file(temp_file_path)

weatherrouting/__init__.py

@@ -13,7 +13,7 @@
 
 # For detail about GNU see <http://www.gnu.org/licenses/>.
 from .grib import Grib  # noqa: F401
-from .polar import Polar  # noqa: F401
+from .polar import Polar, PolarError  # noqa: F401
 from .routers import *  # noqa: F401, F403
 from .routing import Routing, list_routing_algorithms  # noqa: F401
 from .utils import *  # noqa: F401, F403

weatherrouting/polar.py

@@ -15,10 +15,15 @@
 
 # For detail about GNU see <http://www.gnu.org/licenses/>.
 import math
+import re
 from io import TextIOWrapper
 from typing import Dict, Optional, Tuple
 
 
+class PolarError(Exception):
+    pass
+
+
 class Polar:
     def __init__(self, polar_path: str, f: Optional[TextIOWrapper] = None):
         """
@@ -29,6 +34,7 @@ def __init__(self, polar_path: str, f: Optional[TextIOWrapper] = None):
         f : File
                 File object for passing an opened file
         """
+        self.validate_file(polar_path)
 
         self.tws = []
         self.twa = []
@@ -189,3 +195,98 @@ def get_twa_routage(self, tws: float, twa: float) -> float:
             if twa > twadown:
                 twa = twadown
         return twa
+
+    # ---- Start validate function ----
+    @staticmethod
+    def validate_file(filepath):
+        """Validates the structure and content of a polar file.
+
+        Returns True if valid, raises PolarError with specific message if invalid.
+        """
+        with open(filepath, "r") as f:
+            content = f.read()
+        lines = content.strip().split("\n")
+
+        # Check for empty file
+        if len(lines) == 1 and not lines[0] or not lines[0]:
+            raise PolarError("EMPTY_FILE")
+
+        # Process header (wind speeds)
+        Polar._validate_header(lines[0])
+
+        # Check data rows
+        header_parts = re.split(r"\s+", lines[0].strip())
+        expected_columns = len(header_parts)
+
+        for line in lines[1:]:
+            Polar._validate_data_row(line, expected_columns)
+
+        return True
+
+    @staticmethod
+    def _validate_header(header_line):
+        """Validates the header line containing wind speeds."""
+        header_parts = re.split(r"\s+", header_line.strip())
+
+        # Try to parse wind speeds (should be numeric)
+        try:
+            tws = [float(ws) for ws in header_parts[1:]]
+        except ValueError:
+            raise PolarError("WIND_SPEED_NOT_NUMERIC")
+
+        # Check for increasing wind speeds
+        if not all(tws[i] <= tws[i + 1] for i in range(len(tws) - 1)):
+            raise PolarError("WIND_SPEEDS_NOT_INCREASING")
+
+        return True
+
+    @staticmethod
+    def _validate_data_row(line, expected_columns):
+        """Validates a single data row in the polar file."""
+        parts = re.split(r"\s+", line.strip())
+
+        # Skip empty lines
+        if not parts or (len(parts) == 1 and not parts[0]):
+            raise PolarError("EMPTY_LINE")
+
+        # Check number of columns
+        if len(parts) != expected_columns:
+            raise PolarError("COLUMN_COUNT_MISMATCH")
+
+        # Validate TWA
+        Polar._validate_twa(parts[0])
+
+        # Validate boat speeds
+        for speed in parts[1:]:
+            Polar._validate_boat_speed(speed)
+
+        return True
+
+    @staticmethod
+    def _validate_twa(twa_str):
+        """Validates a TWA (True Wind Angle) value."""
+        try:
+            twa = float(twa_str)
+            if twa < 0 or twa > 180:
+                raise PolarError("TWA_OUT_OF_RANGE")
+        except ValueError:
+            raise PolarError("TWA_NOT_NUMERIC")
+
+        return True
+
+    @staticmethod
+    def _validate_boat_speed(speed_str):
+        """Validates a boat speed value."""
+        if speed_str in ["", "-", "NaN", "NULL"]:
+            raise PolarError("EMPTY_VALUE")
+
+        try:
+            boat_speed = float(speed_str)
+            if boat_speed < 0:
+                raise PolarError("NEGATIVE_SPEED")
+        except ValueError:
+            raise PolarError("SPEED_NOT_NUMERIC")
+
+        return True
+
+    # ---- End validate function ----