/// <summary>
/// Verifies that <paramref name="x"/> and <paramref name="y"/> are not equal.
/// </summary>
/// <typeparam name="T">The type of the two objects to compare.</typeparam>
/// <param name="x">The first object to compare.</param>
/// <param name="y">The second object to compare.</param>
/// <param name="comparer">
/// The equality comparer to use for comparing the two objects,
/// or <see langword="null"/> to use the <see cref="EqualityComparer{T}.Default"/> comparer
/// for type <typeparamref name="T"/>.
/// </param>
/// <param name="message">A message to display if the assertion fails. This message can be seen in the unit test results.</param>
public static void NotEquals <T>(T x, T y, IEqualityComparer <T> comparer = null, string message = null)
{
if (comparer == null)
{
comparer = EqualityComparer <T> .Default;
}
if (comparer.Equals(x, y))
{
var xStr = AssertUtility.FormatArgument(x);
var yStr = AssertUtility.FormatArgument(y);
var comparerStr = GetComparerName(comparer);
Assert.Fail($"Value {xStr} is equal to {yStr} under the {comparerStr} comparer. Expected not to be equal. {message}");
}
}
private static string GetComparerName <T>(IEqualityComparer <T> comparer)
{
string comparerStr = comparer.ToString();
if (comparerStr == comparer.GetType().ToString())
{
comparerStr = comparer.GetType().Name;
}
comparerStr = AssertUtility.FormatArgument(comparerStr);
if (comparer == EqualityComparer <T> .Default)
{
comparerStr += " (default)";
}
return(comparerStr);
}
private static void CompareInner <T>(T x, T y, IComparer <T> comparer, Func <int, bool> comparisonCheck, string expectedResult, string message)
{
if (comparer == null)
{
comparer = Comparer <T> .Default;
}
int comparisonResult = comparer.Compare(x, y);
if (!comparisonCheck(comparisonResult))
{
var xStr = AssertUtility.FormatArgument(x);
var yStr = AssertUtility.FormatArgument(y);
var comparerStr = GetComparerName(comparer);
var comparisonStr =
comparisonResult == 0 ? "equal to" :
comparisonResult < 0 ? "less than" : "greater than";
throw new AssertFailedException($"Value {xStr} is {comparisonStr} {yStr} under the {comparerStr} comparer. Expected to be {expectedResult}. {message}");
}
}
