TrivialUnitTests.cs

static void Main()
{
    Test_PrimeFactorsOf14ShouldBe3();
    Test_PrimeFactorsOf14ShouldBe1_2_7();
}

static void Test_PrimeFactorsOf14ShouldBe3()
{
    var result = CalculatePrimeFactors(3);
    if (!result.SequenceEqual(new[] { 3 }))
    {
        throw new Exception();
    }
}

static void Test_PrimeFactorsOf14ShouldBe1_2_7()
{
    var result = CalculatePrimeFactors(14);
    if (!result.SequenceEqual(new[] { 1, 2, 7 }))
    {
        throw new Exception();
    }
}