Trait that provides an implicit conversion that adds value
(when you expect a Right)
and left.value
(when you expect a Left) methods
to Either
, which will return the selected value of the Either
if defined,
or throw TestFailedException
if not.
This construct allows you to express in one statement that an Either
should be left or right
and that its value should meet some expectation. Here's are some examples:
either1.value should be > 9 either2.left.value should be ("Muchos problemas")
Or, using assertions instead of matcher expressions:
assert(either1.value > 9) assert(either2.left.value === "Muchos problemas")
Were you to simply invoke left.get
on the Either
,
if the Either
wasn't defined as expected (e.g., it was a Right
when you expected a Left
), it
would throw a NoSuchElementException
:
val either: Either[String, Int] = Right(9) either.left.get should be > "Muchos problemas" // either.right.get throws NoSuchElementException
The NoSuchElementException
would cause the test to fail, but without providing a stack depth pointing
to the failing line of test code. This stack depth, provided by TestFailedException
(and a
few other ScalaTest exceptions), makes it quicker for
users to navigate to the cause of the failure. Without EitherValues
, to get
a stack depth exception you would need to make two statements, like this:
val either: Either[String, Int] = Right(9) either should be ('left) // throws TestFailedException either.left.get should be > "Muchos problemas"
The EitherValues
trait allows you to state that more concisely:
val either: Either[String, Int] = Left("Muchas problemas") either.left.value should be > 9 // either.left.value throws TestFailedException
- Companion:
- object
Type members
Classlikes
Wrapper class that adds a value
method to Either
, allowing
you to make statements to inspect the value if a Right, like:
Wrapper class that adds a value
method to Either
, allowing
you to make statements to inspect the value if a Right, like:
either.value should be > 9
- Value parameters:
- either
An
Either
to convert toEitherValuable
, which provides thevalue
method.
Wrapper class that adds a value
method to LeftProjection
, allowing
you to make statements like:
Wrapper class that adds a value
method to LeftProjection
, allowing
you to make statements like:
either.left.value should be > 9
- Value parameters:
- leftProj
A
LeftProjection
to convert toLeftValuable
, which provides thevalue
method.
Wrapper class that adds a value
method to RightProjection
, allowing
you to make statements like:
Wrapper class that adds a value
method to RightProjection
, allowing
you to make statements like:
either.right.value should be > 9
- Value parameters:
- rightProj
A
RightProjection
to convert toRightValuable
, which provides thevalue
method.
Implicits
Implicits
Implicit conversion that adds a value
method to Either
.
This method is right biased and is the equivalent of calling either.right.value
.
Implicit conversion that adds a value
method to Either
.
This method is right biased and is the equivalent of calling either.right.value
.
- Value parameters:
- either
the
Either
on which to add thevalue
method
Implicit conversion that adds a value
method to LeftProjection
.
Implicit conversion that adds a value
method to LeftProjection
.
- Value parameters:
- leftProj
the
LeftProjection
on which to add thevalue
method
Deprecated implicits
Implicit conversion that adds a value
method to RightProjection
.
Implicit conversion that adds a value
method to RightProjection
.
- Value parameters:
- rightProj
the
RightProjection
on which to add thevalue
method
- Deprecated