diff --git a/X10D.Tests/1000primes.txt b/X10D.Tests/1000primes.txt
new file mode 100644
index 0000000..1d931b0
--- /dev/null
+++ b/X10D.Tests/1000primes.txt
@@ -0,0 +1,1000 @@
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\ No newline at end of file
diff --git a/X10D.Tests/X10D.Tests.csproj b/X10D.Tests/X10D.Tests.csproj
index a1349f5..533eb28 100644
--- a/X10D.Tests/X10D.Tests.csproj
+++ b/X10D.Tests/X10D.Tests.csproj
@@ -23,4 +23,9 @@
+
+
+
+
+
diff --git a/X10D.Tests/src/Core/IsPrimeTests.cs b/X10D.Tests/src/Core/IsPrimeTests.cs
new file mode 100644
index 0000000..9d12634
--- /dev/null
+++ b/X10D.Tests/src/Core/IsPrimeTests.cs
@@ -0,0 +1,121 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace X10D.Tests.Core
+{
+ ///
+ /// Tests for .
+ ///
+ ///
+ /// Tests for this extension method are delegated to their own test class because of the non-trivial requirements for
+ /// loading testing prime numbers.
+ ///
+ ///
+ [TestClass]
+ public class IsPrimeTests
+ {
+ private IReadOnlyList _primeNumbers = ArraySegment.Empty;
+
+ [TestInitialize]
+ public void Initialize()
+ {
+ _primeNumbers = LoadPrimes();
+ Assert.AreEqual(1000, _primeNumbers.Count);
+ }
+
+ ///
+ /// Asserts the primality of the first 1000 known prime numbers.
+ ///
+ [TestMethod]
+ public void First1000Primes()
+ {
+ for (var index = 0; index < _primeNumbers.Count; index++)
+ {
+ var value = _primeNumbers[index];
+ var result = value.IsPrime();
+ Assert.IsTrue(result, value.ToString("N0", CultureInfo.InvariantCulture));
+ }
+ }
+
+ ///
+ /// Asserts that all negative numbers are not prime.
+ ///
+ [TestMethod]
+ public void Negatives()
+ {
+ for (var value = short.MinValue; value < 0; value++)
+ {
+ var result = value.IsPrime();
+ Assert.IsFalse(result, value.ToString("N0", CultureInfo.InvariantCulture));
+ }
+ }
+
+ ///
+ /// Asserts that all negative numbers are not prime.
+ ///
+ [TestMethod]
+ public void LessThan2()
+ {
+ for (var value = 0; value < 2; value++)
+ {
+ var result = value.IsPrime();
+ Assert.IsFalse(result, value.ToString("N0", CultureInfo.InvariantCulture));
+ }
+ }
+
+ ///
+ /// Tests the primality of the numbers 0 - 7919.
+ ///
+ [TestMethod]
+ public void ZeroTo7919()
+ {
+ for (var value = 0; value < 7920; value++)
+ {
+ var expected = _primeNumbers.Contains(value);
+ var actual = value.IsPrime();
+
+ Assert.AreEqual(expected, actual, value.ToString("N0", CultureInfo.InvariantCulture));
+ }
+ }
+
+ ///
+ /// Tests the primality of the numbers 0 - .
+ ///
+ [TestMethod]
+ public void ZeroToByteMaxValue()
+ {
+ for (byte value = 0; value < byte.MaxValue; value++)
+ {
+ var expected = _primeNumbers.Contains(value);
+ var actual = value.IsPrime();
+
+ Assert.AreEqual(expected, actual, value.ToString("N0", CultureInfo.InvariantCulture));
+ }
+ }
+
+ private static IReadOnlyList LoadPrimes()
+ {
+ using var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("X10D.Tests.1000primes.txt");
+ Assert.IsNotNull(stream);
+
+ using var reader = new StreamReader(stream, Encoding.UTF8);
+ var primes = new List();
+
+ while (reader.ReadLine() is { } line)
+ {
+ if (int.TryParse(line, out var prime))
+ {
+ primes.Add(prime);
+ }
+ }
+
+ return primes.AsReadOnly();
+ }
+ }
+}