public void AffineHash_Hash_Distributes_Byte_Array()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <byte[]> values = AffineHashTests.RandomByteArrays(random, 101, 10000);
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_Char()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <char> values = Enumerable.Range(char.MinValue, char.MaxValue - char.MinValue + 1)
.Select(n => (char)n);
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_Byte()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <byte> values = Enumerable.Range(byte.MinValue, byte.MaxValue - byte.MinValue + 1)
.Select(n => (byte)n);
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_UInt16()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <ushort> values = Enumerable.Range(ushort.MinValue, ushort.MaxValue - ushort.MinValue + 1)
.Select(n => (ushort)n);
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_UInt64()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <ulong> values = AffineHashTests.RandomByteArrays(random, sizeof(ulong), 10000)
.Select(b => BitConverter.ToUInt64(b, 0));
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_String()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <string> values = AffineHashTests.RandomCharArrays(random, 101, 10000)
.Select(b => new string(b));
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_Single()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <float> values = AffineHashTests.RandomByteArrays(random, sizeof(float), 10000)
.Select(b => BitConverter.ToSingle(b, 0));
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_Guid()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <Guid> values = AffineHashTests.RandomByteArrays(random, 16, 10000)
.Select(b => new Guid(b));
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_Decimal()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <decimal> values = Enumerable.Range(0, 10000)
.Select(n => new decimal(random.Next(), random.Next(), random.Next(), random.NextDouble() > 0.5D, (byte)random.Next(29)));
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Distributes_DateTimeOffset()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
IEnumerable <DateTimeOffset> values = AffineHashTests.RandomByteArrays(random, sizeof(ulong), 10000)
.Select(b => new DateTimeOffset((long)(BitConverter.ToUInt64(b, 0) % (ulong)DateTime.MaxValue.Ticks), TimeSpan.FromMinutes(random.Next(-840, 840))));
AffineHashTests.AssertHashDistribution(target, values);
}
public void AffineHash_Hash_Matches_Identical_String_Segments()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
string value = "TestTest";
int expected = target.GetHashCode(value, 0, 4);
int actual = target.GetHashCode(value, 4, 4);
Assert.AreEqual(expected, actual);
}
public void AffineHash_Hash_Matches_Identical_Char_Array_Segments()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
char[] value = { 'T', 'e', 's', 't', 'T', 'e', 's', 't' };
int expected = target.GetHashCode(value, 0, 4);
int actual = target.GetHashCode(value, 4, 4);
Assert.AreEqual(expected, actual);
}
public void AffineHash_Hash_Matches_Identical_Byte_Array_Segments()
{
Random random = AffineHashTests.Random();
AffineHash target = new AffineHash(random);
byte[] value = { 0, 1, 2, 3, 0, 1, 2, 3 };
int expected = target.GetHashCode(value, 0, 4);
int actual = target.GetHashCode(value, 4, 4);
Assert.AreEqual(expected, actual);
}
/// <summary>
/// Generates random character arrays for test data.
/// </summary>
/// <param name="random">The random number generator to use.</param>
/// <param name="length">The length of each character array.</param>
/// <param name="count">The total number of character arrays to generate.</param>
/// <returns>A list of random character arrays.</returns>
private static IEnumerable <char[]> RandomCharArrays(Random random, int length, int count)
{
char[] buffer = new char[length];
foreach (byte[] bytes in AffineHashTests.RandomByteArrays(random, length * sizeof(char), count))
{
int o = 0;
for (int i = 0; i < buffer.Length; i++)
{
buffer[i] = BitConverter.ToChar(bytes, o);
o += sizeof(char);
}
yield return(buffer);
}
}
public void AffineHash_Hash_Rejects_Invalid_Arguments()
{
var cases = new[]
{
new { arguments = new object[] { null }, types = new Type[] { typeof(byte[]) }, expected = typeof(ArgumentNullException) },
new { arguments = new object[] { null }, types = new Type[] { typeof(char[]) }, expected = typeof(ArgumentNullException) },
new { arguments = new object[] { null }, types = new Type[] { typeof(string) }, expected = typeof(ArgumentNullException) },
new { arguments = new object[] { null, 0, 0 }, types = new Type[] { typeof(byte[]), typeof(int), typeof(int) }, expected = typeof(ArgumentNullException) },
new { arguments = new object[] { null, 0, 0 }, types = new Type[] { typeof(char[]), typeof(int), typeof(int) }, expected = typeof(ArgumentNullException) },
new { arguments = new object[] { null, 0, 0 }, types = new Type[] { typeof(string), typeof(int), typeof(int) }, expected = typeof(ArgumentNullException) },
new { arguments = new object[] { new byte[10], -1, 5 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { new byte[10], 10, 5 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { new byte[10], 5, -1 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { new byte[10], 5, 6 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { new char[10], -1, 5 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { new char[10], 10, 5 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { new char[10], 5, -1 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { new char[10], 5, 6 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { "1234567890", -1, 5 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { "1234567890", 10, 5 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { "1234567890", 5, -1 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
new { arguments = new object[] { "1234567890", 5, 6 }, types = (Type[])null, expected = typeof(ArgumentOutOfRangeException) },
};
AffineHash target = new AffineHash(1L, 0L);
for (int i = 0; i < cases.Length; i++)
{
var c = cases[i];
Type[] types = c.types ?? c.arguments.Select(a => a.GetType()).ToArray();
Delegate method = AffineHashTests.HashDelegate(target, types);
try
{
object result = method.DynamicInvoke(c.arguments);
Assert.Fail("index: {0}, return: {1}", i, result);
}
catch (TargetInvocationException ex)
{
Assert.AreEqual(c.expected, ex.InnerException.GetType(), "index: {0}", i);
}
catch (Exception ex)
{
Assert.Fail("index: {0}, exception: {1}", i, ex);
}
}
}
/// <summary>
/// Asserts that the distribution of hash values is uniform for a given set of data.
/// </summary>
/// <typeparam name="T">The type of data to hash.</typeparam>
/// <param name="target">The target hash algorithm.</param>
/// <param name="values">The values to hash.</param>
private static void AssertHashDistribution <T>(AffineHash target, IEnumerable <T> values)
{
Distribution distribution = new Distribution();
Dictionary <int, T> hashes = new Dictionary <int, T>();
Func <T, int> method = (Func <T, int>)AffineHashTests.HashDelegate(target, typeof(T));
foreach (T value in values)
{
int hash = method(value);
distribution.Observe(hash);
if (hashes.ContainsKey(hash))
{
Assert.Fail("scale:{0}, shift:{1}, hash:{2}, original:{3}, collision:{4}", target.Scale, target.Shift, hash, hashes[hash], value);
}
else
{
hashes.Add(hash, value);
}
}
double ks = distribution.Finish();
Assert.IsTrue(ks < 0.1D, "scale:{0}, shift:{1}, ks:{2}", target.Scale, target.Shift, ks);
}
