ModifiableMessage
Trait implemented by exception types that can modify their detail message.
This trait facilitates the withClue
construct provided by trait
Assertions
. This construct enables extra information (or "clues") to
be included in the detail message of a thrown exception. Although both
assert
and expect
provide a way for a clue to be
included directly, assertThrows
, intercept
, and ScalaTest matcher expressions
do not. Here's an example of clues provided directly in assert
:
assert(1 + 1 === 3, "this is a clue")
and in expect
:
expect(3, "this is a clue") { 1 + 1 }
The exceptions thrown by the previous two statements will include the clue
string, "this is a clue"
, in the exceptions detail message.
To get the same clue in the detail message of an exception thrown
by a failed assertThrows
call requires using withClue
:
withClue("this is a clue") { assertThrows[IndexOutOfBoundsException] { "hi".charAt(-1) } }
Similarly, to get a clue in the exception resulting from an exception arising out
of a ScalaTest matcher expression, you need to use withClue
. Here's
an example:
withClue("this is a clue") { 1 + 1 should === (3) }
Exception types that mix in this trait have a modifyMessage
method, which
returns an exception identical to itself, except with the detail message option replaced with
the result of invoking the passed function, supplying the current detail message option
as the lone String
parameter.
Value members
Abstract methods
Returns an instance of this exception's class, identical to this exception,
except with the detail message option replaced with
the result of invoking the passed function, fun
, supplying the current detail message option
as the lone Option[String]
parameter.
Returns an instance of this exception's class, identical to this exception,
except with the detail message option replaced with
the result of invoking the passed function, fun
, supplying the current detail message option
as the lone Option[String]
parameter.
Implementations of this method may either mutate this exception or return a new instance with the revised detail message.
- Value parameters:
- fun
A function that returns the new detail message option given the old one.