public void SecondFunctorLawHoldsForSelectLeft(IEither <string, int> e)
{
bool f(int x) => x % 2 == 0;
int g(string s) => s.Length;
Assert.Equal(
e.SelectLeft(x => f(g(x))),
e.SelectLeft(g).SelectLeft(f));
}
public void ConsistencyLawHolds(IEither <string, int> e)
{
bool f(string s) => string.IsNullOrWhiteSpace(s);
DateTime g(int i) => new DateTime(i);
Assert.Equal(e.SelectBoth(f, g), e.SelectRight(g).SelectLeft(f));
Assert.Equal(
e.SelectLeft(f).SelectRight(g),
e.SelectRight(g).SelectLeft(f));
}
public void SelectLeftObeysFirstFunctorLaw(IEither <string, int> e)
{
Assert.Equal(e, e.SelectLeft(Id));
}