public void SecondFunctorLawHoldsForMapRight(IEitherValueType <string, int> e)
{
char f(bool b) => b ? 'T' : 'F';
bool g(int i) => i % 2 == 0;
Assert.AreEqual(e.MapRight(x => f(g(x))), e.MapRight(g).MapRight(f));
}
public void SecondFunctorLawHoldsForMapLeft(IEitherValueType <string, int> e)
{
bool f(int x) => x % 2 == 0;
int g(string s) => s.Length;
Assert.AreEqual(e.MapLeft(x => f(g(x))), e.MapLeft(g).MapLeft(f));
}
public void ConsistencyLawHolds(IEitherValueType <string, int> e)
{
bool f(string s) => string.IsNullOrWhiteSpace(s);
DateTime g(int i) => new DateTime(i);
Assert.AreEqual(e.Map(f, g), e.MapRight(g).MapLeft(f));
Assert.AreEqual(
e.MapLeft(f).MapRight(g),
e.MapRight(g).MapLeft(f));
}
public void MapCompositionLawHolds(IEitherValueType <string, int> e)
{
bool f(int x) => x % 2 == 0;
int g(string s) => s.Length;
char h(bool b) => b ? 'T' : 'F';
bool i(int x) => x % 2 == 0;
Assert.AreEqual(
e.Map(x => f(g(x)), y => h(i(y))),
e.Map(g, i).Map(f, h));
}
public void MapOnExtensionMethodObeysFirstFunctorLaw(IEitherValueType <string, int> e)
{
e.Should().Be(e.Map(l => Identity(l), r => Identity(r)));
}
public void MapLeftObeysFirstFunctorLaw(IEitherValueType <string, int> e)
{
e.Should().Be(e.MapLeft(l => Identity(l)));
}
