public void TestSequenceComparer()
{
var a = new[] { 1, 2, 3 };
var b = new[] { 1, 2, 3 };
var c = new[] { 1, 3, 2 };
var comparer = EqualityComparers.GetSequenceComparer <int>();
Assert.Same(comparer, EqualityComparers.GetSequenceComparer <int>());
Assert.Same(comparer, EqualityComparers.GetSequenceComparer(EqualityComparer <int> .Default));
comparer.Equals(a, b).ShouldEqual(true);
comparer.Equals(a, c).ShouldEqual(false);
comparer.Equals(null, a).ShouldEqual(false);
comparer.Equals(null, null).ShouldEqual(true);
comparer.GetHashCode(null).ShouldEqual(((IEqualityComparer)comparer).GetHashCode(null));
comparer.GetHashCode(a).ShouldEqual(comparer.GetHashCode(b));
Assert.NotEqual(comparer.GetHashCode(a), comparer.GetHashCode(c));
var stringComparer = EqualityComparers.GetSequenceComparer(StringComparer.OrdinalIgnoreCase);
var aa = new[] { "a", "B", "C" };
var bb = new[] { "A", "b", "c" };
var cc = new[] { "a", "B", "C", "d" };
stringComparer.Equals(aa, bb).ShouldEqual(true);
stringComparer.Equals(aa, cc).ShouldEqual(false);
stringComparer.GetHashCode(aa).ShouldEqual(stringComparer.GetHashCode(bb));
Assert.NotEqual(stringComparer.GetHashCode(aa), stringComparer.GetHashCode(cc));
}
public void TestCreateByKey()
{
var comparer = EqualityComparers.Create((string s) => s.Length);
comparer.Equals("a", "b").ShouldEqual(true);
comparer.Equals(null, string.Empty).ShouldEqual(false);
comparer.Equals(string.Empty, null).ShouldEqual(false);
comparer.Equals("aa", "b").ShouldEqual(false);
comparer.GetHashCode("abc").ShouldEqual(3);
}
public void TestRapidExit()
{
var comparer = EqualityComparers.Create(
(int a, int b) => { throw new InvalidOperationException("should never get here"); },
i => { throw new InvalidOperationException("should never get here"); }
);
Sequence <int>().CollectionEquals(Sequence <int>(), comparer).ShouldEqual(true);
new int[0].CollectionEquals(new int[0], comparer).ShouldEqual(true);
new[] { 1, 2, 3 }.CollectionEquals(new[] { 1, 2, 3, 4 }).ShouldEqual(false);
}
public void TestComparerEquality()
{
Func <string, string, bool> sameLength = (a, b) => a.Length == b.Length;
Func <string, int> getLength = s => s.Length;
ComparersTest.TestEquality(EqualityComparers.Create(sameLength, getLength), EqualityComparers.Create(sameLength, getLength), EqualityComparers.Create(getLength));
ComparersTest.TestEquality(EqualityComparers.Create(getLength), EqualityComparers.Create(getLength, EqualityComparer <int> .Default), EqualityComparers.Create((string s) => s[0]));
ComparersTest.TestEquality(EqualityComparers.GetReferenceComparer <string>(), EqualityComparers.GetReferenceComparer <string>(), EqualityComparer <string> .Default);
ComparersTest.TestEquality(EqualityComparers.GetCollectionComparer(EqualityComparer <string> .Default), EqualityComparers.GetCollectionComparer <string>(), EqualityComparers.GetCollectionComparer(StringComparer.OrdinalIgnoreCase));
ComparersTest.TestEquality(EqualityComparers.GetSequenceComparer(StringComparer.Ordinal), EqualityComparers.GetSequenceComparer(StringComparer.Ordinal), EqualityComparers.GetCollectionComparer(StringComparer.Ordinal));
}
public void TestReferenceComparer()
{
var referenceComparer = EqualityComparers.GetReferenceComparer <string>();
Assert.Same(referenceComparer, EqualityComparers.GetReferenceComparer <string>());
referenceComparer.Equals(new string('a', 1), new string('a', 1)).ShouldEqual(false);
var text = new string('a', 1);
referenceComparer.Equals(text, text).ShouldEqual(true);
referenceComparer.GetHashCode(text).ShouldEqual(referenceComparer.GetHashCode(text));
referenceComparer.Equals(text, null).ShouldEqual(false);
referenceComparer.Equals(null, null).ShouldEqual(true);
var obj = new object();
EqualityComparers.GetReferenceComparer <object>().GetHashCode(obj)
.ShouldEqual(obj.GetHashCode());
}
public void TestCreate()
{
Assert.Throws <ArgumentNullException>(() => EqualityComparers.Create <int>(null));
var comparer = EqualityComparers.Create <string>((a, b) => a.Length == b.Length);
comparer.Equals("a", "b").ShouldEqual(true);
comparer.Equals(null, string.Empty).ShouldEqual(false);
comparer.Equals(string.Empty, null).ShouldEqual(false);
comparer.Equals("aa", "b").ShouldEqual(false);
comparer.GetHashCode("abc").ShouldEqual(-1);
comparer = EqualityComparers.Create <string>((a, b) => a.Length == b.Length, s => s.Length);
comparer.Equals("a", "b").ShouldEqual(true);
comparer.Equals(null, string.Empty).ShouldEqual(false);
comparer.Equals(string.Empty, null).ShouldEqual(false);
comparer.Equals("aa", "b").ShouldEqual(false);
comparer.GetHashCode("abc").ShouldEqual(3);
}