Add tests for TrialDivisionFactorizer (#320)

Author: MatthiasHeinz

Algorithms.Tests/Numeric/Factorization/TrialDivisionFactorizerTests.cs

@@ -1,4 +1,4 @@
-using Algorithms.Numeric.Factorization;
+using Algorithms.Numeric.Factorization;
 using NUnit.Framework;
 
 namespace Algorithms.Tests.Numeric.Factorization
@@ -21,5 +21,27 @@ public static void PrimeNumberFactorizationFails(int p)
             // Assert
             Assert.IsFalse(success);
         }
+
+        [Test]
+        [TestCase(4, 2)]
+        [TestCase(6, 2)]
+        [TestCase(8, 2)]
+        [TestCase(9, 3)]
+        [TestCase(15, 3)]
+        [TestCase(35, 5)]
+        [TestCase(49, 7)]
+        [TestCase(77, 7)]
+        public static void PrimeNumberFactorizationSucceeds(int n, int expected)
+        {
+            // Arrange
+            var factorizer = new TrialDivisionFactorizer();
+
+            // Act
+            var success = factorizer.TryFactor(n, out var factor);
+
+            // Assert
+            Assert.IsTrue(success);
+            Assert.AreEqual(expected, factor);
+        }
     }
 }

Algorithms/Numeric/Factorization/TrialDivisionFactorizer.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Linq;
 
 namespace Algorithms.Numeric.Factorization
@@ -9,7 +9,7 @@ namespace Algorithms.Numeric.Factorization
     public class TrialDivisionFactorizer : IFactorizer
     {
         /// <summary>
-        ///     Finds a factor of a given number or returns false if it's prime.
+        ///     Finds the smallest non trivial factor (i.e.: 1 &lt; factor &lt;= sqrt(<paramref name="n" />)) of a given number or returns false if it's prime.
         /// </summary>
         /// <param name="n">Integer to factor.</param>
         /// <param name="factor">Found factor.</param>