public void DifferentReturnErrorIsNotEqual()
{
var value = "SomeErr";
var monad = new ErrorMonad <Int32>(value);
var asserterVisitor = new AssertErrorVisitor <Int32>
{
ExpectedError = "SomeOtherErr",
AreEqual = false
};
monad.Accept(asserterVisitor);
}
public void ReturnErrorIsEqualEvenForInt()
{
var value = "error";
var monad = new ErrorMonad <Int32>(value);
var asserterVisitor = new AssertErrorVisitor <Int32>
{
ExpectedError = value,
AreEqual = true
};
monad.Accept(asserterVisitor);
}
public void BindPropagatesTheError()
{
var errMessage = "error message";
var firstMonad = new ErrorMonad <Int32>(errMessage);
var secondMonad = firstMonad.Bind(val => new ValueMonad <Int32>(val + 1));
var asserterVisitor = new AssertErrorVisitor <Int32>
{
ExpectedError = errMessage,
AreEqual = true
};
secondMonad.Accept(asserterVisitor);
}
public void BindPropagatesTheErrorMore()
{
var errMessage = "error message";
var asserterVisitor = new AssertErrorVisitor <Int32>
{
ExpectedError = errMessage,
AreEqual = true
};
new ErrorMonad <Int32>(errMessage)
.Bind(val => new ValueMonad <Int32>(val + 1))
.Bind(val => new ValueMonad <Int32>(val + 2))
.Bind(val => new ValueMonad <Int32>(val + 3))
.Bind(val => new ValueMonad <Int32>(val + 4))
.Accept(asserterVisitor);
}
public void BindDoesntExecuteAfterError()
{
var errMessage = "error message";
var asserterVisitor = new AssertErrorVisitor <Int32>
{
ExpectedError = errMessage,
AreEqual = true
};
ErrorMonad <Int32> Fail(Int32 value)
{
Assert.Fail();
return(new ErrorMonad <Int32>("This should never execute"));
}
Assert.DoesNotThrow(() => new ErrorMonad <Int32>(errMessage).Bind(Fail));
}
