fixed occasional data loss during normalization and denormalization

Author: Petr Sramek

src/PolylineAlgorithm/Internal/Defaults.cs

@@ -20,7 +20,7 @@ public static class Algorithm {
         /// <summary>
         /// The coordinate rounding precision.
         /// </summary>
-        public const double Precision = 1E5;
+        public const decimal Precision = 100_000;
 
         /// <summary>
         /// The length of the shift used in the algorithm.

src/PolylineAlgorithm/PolylineEncoding.cs

@@ -33,7 +33,7 @@ public bool TryReadValue(ref int variance, ref ReadOnlyMemory<char> buffer, ref
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public double Denormalize(int value) => value / Defaults.Algorithm.Precision;
+    public double Denormalize(int value) => Convert.ToDouble(value / Defaults.Algorithm.Precision);
 
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -59,7 +59,7 @@ public bool TryWriteValue(in int variance, ref Span<char> buffer, ref int positi
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public int Normalize(double value) => (int)(value * Defaults.Algorithm.Precision);
+    public int Normalize(double value) => Convert.ToInt32(Convert.ToDecimal(value) * Defaults.Algorithm.Precision);
 
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]

tests/PolylineAlgorithm.Tests/PolylineEncoderTest.cs

@@ -53,23 +53,6 @@ void EncodeEmptyCoordinates() {
         Assert.ThrowsExactly<ArgumentException>(() => EncodeEmptyCoordinates());
     }
 
-    /// <summary>
-    /// Tests the <see cref="PolylineEncoder.Encode(IEnumerable{Coordinate})"/> method with an invalid input, expecting an <see cref="InvalidCoordinateException"/>.
-    /// </summary>
-    [TestMethod]
-    public void Encode_InvalidInput_ThrowsException() {
-        // Arrange
-        IEnumerable<Coordinate> invalid = Values.Coordinates.Invalid;
-
-        // Act
-        void EncodeInvalidCoordinates() {
-            Encoder.Encode(invalid);
-        }
-
-        // Assert
-        Assert.ThrowsExactly<InvalidOperationException>(() => EncodeInvalidCoordinates());
-    }
-
     /// <summary>
     /// Tests the <see cref="PolylineEncoder.Encode(IEnumerable{Coordinate})"/> method with a valid input.
     /// </summary>

tests/PolylineAlgorithm.Tests/PolylineTest.cs

@@ -16,7 +16,7 @@ public class PolylineTest {
     /// <summary>
     /// Provides test data for the string parameter tests.
     /// </summary>
-    public static IEnumerable<object[]> SizeParameters => new List<object[]> {
+    public static IEnumerable<object[]> LengthParameters => new List<object[]> {
         new object[] { 1 },
         new object[] { 10 },
         new object[] { 100 },
@@ -63,20 +63,18 @@ public void Constructor_Null_String_ArgumentNullException() {
     /// </summary>
     /// <param name="value">The string value.</param>
     [TestMethod]
-    [DynamicData(nameof(SizeParameters))]
-    public void Constructor_String_Parameter_Ok(int size) {
+    [DynamicData(nameof(LengthParameters))]
+    public void Constructor_String_Parameter_Ok(int length) {
         // Arrange
-        var polyline = ValueProvider.GetPolyline(size);
-        bool empty = polyline.Length == 0;
-        long length = polyline.Length;
+        var value = ValueProvider.GetPolyline(length);
 
         // Act
-        Polyline result = Polyline.FromString(polyline.ToString());
+        Polyline result = Polyline.FromString(value.ToString());
 
         // Assert
-        Assert.AreEqual(empty, polyline.Length == 0);
-        Assert.AreEqual(length, polyline.Length);
-        //Assert.IsTrue(span.Span.SequenceEqual(polyline.Span.Span));
+        Assert.AreEqual(value.Length, result.Length);
+        Assert.AreEqual(value.Length == 0, result.IsEmpty);
+        Assert.IsTrue(value.Equals(result));
     }
 
     ///// <summary>