public void TestSetComparer()
{
IEqualityComparer <TreeSet <int> > setComparer = TreeSet <int> .CreateSetComparer();
Assert.True(setComparer.Equals(TreeSet <int> .CreateSetComparer()));
Assert.False(setComparer.Equals(null));
Assert.Equal(setComparer.GetHashCode(), TreeSet <int> .CreateSetComparer().GetHashCode());
var set = new TreeSet <int>();
var other = new TreeSet <int>();
// Test behavior with nulls
Assert.True(setComparer.Equals(null, null));
Assert.False(setComparer.Equals(set, null));
Assert.False(setComparer.Equals(null, set));
Assert.Equal(0, setComparer.GetHashCode(null));
// Test behavior with empty sets
Assert.True(setComparer.Equals(set, other));
Assert.Equal(setComparer.GetHashCode(set), setComparer.GetHashCode(other));
// Test behavior with non-empty sets
set.UnionWith(Enumerable.Range(0, 10));
Assert.False(setComparer.Equals(set, other));
other.UnionWith(Enumerable.Range(0, 5));
Assert.False(setComparer.Equals(set, other));
other.UnionWith(Enumerable.Range(5, 5));
Assert.True(setComparer.Equals(set, other));
Assert.Equal(setComparer.GetHashCode(set), setComparer.GetHashCode(other));
// Test behavior with non-empty sets with different comparers
set.Clear();
other = new TreeSet <int>(ZeroHashCodeEqualityComparer <int> .Default);
set.UnionWith(Enumerable.Range(0, 10));
Assert.False(setComparer.Equals(set, other));
other.UnionWith(Enumerable.Range(0, 5));
Assert.False(setComparer.Equals(set, other));
other.UnionWith(Enumerable.Range(5, 5));
Assert.True(setComparer.Equals(set, other));
Assert.Equal(setComparer.GetHashCode(set), setComparer.GetHashCode(other));
}
