added initial CoordinateVarianceTests

Author: petesramek

tests/PolylineAlgorithm.Abstraction.Tests/Internal/CoordinateVarianceTest.cs

@@ -0,0 +1,40 @@
+namespace PolylineAlgorithm.Abstraction.Tests.Internal;
+
+using PolylineAlgorithm.Abstraction.Internal;
+
+[TestClass]
+public class CoordinateVarianceTests {
+    public static IEnumerable<(int Latitude, int Longitude)> Coordinates => [
+        (0, 0),
+        (10, 20),
+        (-10, -20),
+        (100, 200),
+        (-100, -200),
+        (123456789, 987654321),
+        (-123456789, -987654321)
+    ];
+
+    [TestMethod]
+    public void Constructor_Ok() {
+        // Arrange & Act
+        CoordinateVariance variance = new();
+        // Assert
+        Assert.AreEqual(0, variance.Latitude);
+        Assert.AreEqual(0, variance.Longitude);
+    }
+
+    [TestMethod]
+    [DynamicData(nameof(Coordinates), DynamicDataSourceType.Property)]
+    public void Next_Ok(int latitude, int longitude) {
+        // Arrange
+        CoordinateVariance variance = new();
+        var expected = (latitude, longitude);
+
+        // Act
+        variance.Next(latitude, longitude);
+
+        // Assert
+        Assert.AreEqual(expected.latitude, variance.Latitude);
+        Assert.AreEqual(expected.longitude, variance.Longitude);
+    }
+}