trait EitherValues extends Serializable
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
- Source
- EitherValues.scala
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Type Members
- class LeftValuable[L, R] extends Serializable
Wrapper class that adds a
valuemethod toLeftProjection, allowing you to make statements like:Wrapper class that adds a
valuemethod toLeftProjection, allowing you to make statements like:either.left.value should be > 9 - class RightValuable[L, R] extends Serializable
Wrapper class that adds a
valuemethod toRightProjection, allowing you to make statements like:Wrapper class that adds a
valuemethod toRightProjection, allowing you to make statements like:either.right.value should be > 9 - class Valuable[L, R] extends Serializable
Wrapper class that adds a
valuemethod toEither, allowing you to make statements to inspect the value if a Right, like:Wrapper class that adds a
valuemethod toEither, allowing you to make statements to inspect the value if a Right, like:either.value should be > 9
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- implicit def convertEitherToValuable[L, R](either: Either[L, R])(implicit pos: Position): Valuable[L, R]
Implicit conversion that adds a
valuemethod toEither.Implicit conversion that adds a
valuemethod toEither. This method is right biased and is the equivalent of callingeither.right.value.- either
the
Eitheron which to add thevaluemethod
- implicit def convertLeftProjectionToValuable[L, R](leftProj: LeftProjection[L, R])(implicit pos: Position): LeftValuable[L, R]
Implicit conversion that adds a
valuemethod toLeftProjection.Implicit conversion that adds a
valuemethod toLeftProjection.- leftProj
the
LeftProjectionon which to add thevaluemethod
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Deprecated Value Members
- implicit def convertRightProjectionToValuable[L, R](rightProj: RightProjection[L, R])(implicit pos: Position): RightValuable[L, R]
Implicit conversion that adds a
valuemethod toRightProjection.Implicit conversion that adds a
valuemethod toRightProjection.- rightProj
the
RightProjectionon which to add thevaluemethod
- Annotations
- @deprecated
- Deprecated
The .right.value syntax on Either has been deprecated and will be removed in a future version of ScalaTest. Please use .value instead.