Provides methods that can be used in withFixture
implementations to retry tests in various scenarios.
Trait Retries
is intended to help you deal with “flickers”—tests that usually pass, but
occasionally fail. The best way to deal with such tests is to fix them so they always pass. Sometimes, however, this is
not practical. In such cases, flickers can waste your time by forcing you to investigate test failures that turn
out to be flickers. Or worse, like the boy who cried wolf, the flickers may train you an your colleagues to not pay attention
to failures such that you don't notice real problems, at least not in a timely manner.
Trait Retries
offers methods that will retry a failed and/or canceled test once, on the same thread,
with or without a delay. These methods take a block that results in Outcome
,
and are intended to be used in withFixture
methods. You should be very selective about which tests you
retry, retrying those for which you have good evidence to conclude they are flickers. Thus it is recommended you
only retry tests that are tagged with Retryable
, and only tag tests as such once they have flickered
consistently for a while, and only after you invested a reasonable effort into fixing them properly.
Here's an example showing how you might use Retries
:
package org.scalatest.examples.tagobjects.retryable import org.scalatest._ import tagobjects.Retryable class SetSpec extends FlatSpec with Retries { override def withFixture(test: NoArgTest) = { if (isRetryable(test)) withRetry { super.withFixture(test) } else super.withFixture(test) } "An empty Set" should "have size 0" taggedAs(Retryable) in { assert(Set.empty.size === 0) } }
- Companion:
- object
Value members
Concrete methods
Indicates whether the test described by the given TestData
includes the
tag org.scalatest.tags.Retryable
.
Indicates whether the test described by the given TestData
includes the
tag org.scalatest.tags.Retryable
.
This method provides an easy way to selectively retry just tests that are flickering. You can
annotated such problematic tests with Retryable
, and just retry those. Here's
what it might look like:
override def withFixture(test: NoArgTest) = { if (isRetryable(test)) withRetry { super.withFixture(test) } else super.withFixture(test) }
Retries the given block immediately (with no delay) if the Outcome
of executing
the block is either Failed
or Canceled
.
Retries the given block immediately (with no delay) if the Outcome
of executing
the block is either Failed
or Canceled
.
The behavior of this method is defined in the table below. The first two rows show the main "retry" behavior: if
executing the block initially fails, and on retry it succeeds, the result is Canceled
. The purpose of this is
to deal with "flickering" tests by downgrading a failure that succeeds on retry to a cancelation.
Or, if executing the block initially results in Canceled
, and on retry it succeeds, the result
is Succeeded
. The purpose of this is to deal with tests that intermittently cancel by ignoring a cancelation that
succeeds on retry.
In the table below, if the “Retry Outcome
” has just a dash, the block is not retried.
Otherwise, the block is retried on the same thread, with no delay.
First Outcome | Retry Outcome | Result |
---|---|---|
Failed
|
Succeeded
|
Canceled (the Succeeded and Failed are
discarded; the exception from the Failed is the cause of the exception in the Canceled )
|
Canceled
|
Succeeded
|
Succeeded (the Canceled is discarded)
|
Succeeded
|
— |
Succeeded (no retry)
|
Pending
|
— |
Pending (no retry)
|
Failed
|
Failed
|
the first Failed (the second Failed is discarded)
|
Failed
|
Pending
|
the Failed (the Pending is discarded)
|
Failed
|
Canceled
|
the Failed (the Canceled is discarded)
|
Canceled
|
Canceled
|
the first Canceled (the second Canceled is discarded)
|
Canceled
|
Pending
|
the Canceled (the Pending is discarded)
|
Canceled
|
Failed
|
the Failed (the Canceled is discarded)
|
- Value parameters:
- blk
the block to execute and potentially retry
Retries the given block with a given delay if the Outcome
of executing
the block is either Failed
or Canceled
.
Retries the given block with a given delay if the Outcome
of executing
the block is either Failed
or Canceled
.
The behavior of this method is defined in the table below. The first two rows show the main "retry" behavior: if
executing the block initially fails, and on retry it succeeds, the result is Canceled
. The purpose of this is
to deal with "flickering" tests by downgrading a failure that succeeds on retry
to a cancelation.
Or, if executing the block initially results in Canceled
, and on retry it succeeds, the result
is Succeeded
. The purpose of this is to deal with tests that intermittently cancel by ignoring a cancelation that
succeeds on retry.
In the table below, if the “Retry Outcome
” has just a dash, the block is not retried.
Otherwise, the block is retried on the same thread, after sleeping the given delay.
First Outcome | Retry Outcome | Result |
---|---|---|
Failed
|
Succeeded
|
Canceled (the Succeeded and Failed are
discarded; the exception from the Failed is the cause of the exception in the Canceled )
|
Canceled
|
Succeeded
|
Succeeded (the Canceled is discarded)
|
Succeeded
|
— |
Succeeded (no retry)
|
Pending
|
— |
Pending (no retry)
|
Failed
|
Failed
|
the first Failed (the second Failed is discarded)
|
Failed
|
Pending
|
the Failed (the Pending is discarded)
|
Failed
|
Canceled
|
the Failed (the Canceled is discarded)
|
Canceled
|
Canceled
|
the first Canceled (the second Canceled is discarded)
|
Canceled
|
Pending
|
the Canceled (the Pending is discarded)
|
Canceled
|
Failed
|
the Failed (the Canceled is discarded)
|
- Value parameters:
- blk
the block to execute and potentially retry
- delay
the amount of time to sleep before retrying
Retries the given block immediately (with no delay) if the Outcome
of executing
the block is Canceled
.
Retries the given block immediately (with no delay) if the Outcome
of executing
the block is Canceled
.
The behavior of this method is defined in the table below. The first row shows the main "retry" behavior: if
executing the block initially results in Canceled
, and on retry it succeeds, the result is Succeeded
.
The purpose of this is to deal with tests that intermittently cancel by ignoring a cancelation that
succeeds on retry.
In the table below, if the “Retry Outcome
” has just a dash, the block is not retried.
Otherwise, the block is retried on the same thread, with no delay.
First Outcome | Retry Outcome | Result |
---|---|---|
Canceled
|
Succeeded
|
the Succeeded (the Canceled is discarded)
|
Succeeded
|
— |
Succeeded (no retry)
|
Pending
|
— |
Pending (no retry)
|
Failed
|
— |
Failed (no retry)
|
Canceled
|
Canceled
|
the first Canceled (the second Canceled is discarded)
|
Canceled
|
Pending
|
the Canceled (the Pending is discarded)
|
Canceled
|
Failed
|
the Failed (the Canceled is discarded)
|
- Value parameters:
- blk
the block to execute and potentially retry
Retries the given block after the given delay if the Outcome
of executing
the block is Canceled
.
The behavior of this method is defined in the table below. The first row shows the main "retry" behavior: if
executing the block initially results in Canceled
, and on retry it succeeds, the result is Succeeded
.
The purpose of this is to deal with tests that intermittently cancel by ignoring a cancelation that
succeeds on retry.
In the table below, if the “Retry Outcome
” has just a dash, the block is not retried.
Otherwise, the block is retried on the same thread, after the given delay.
First Outcome | Retry Outcome | Result |
---|---|---|
Canceled
|
Succeeded
|
the Succeeded (the Canceled is discarded)
|
Succeeded
|
— |
Succeeded (no retry)
|
Pending
|
— |
Pending (no retry)
|
Failed
|
— |
Failed (no retry)
|
Canceled
|
Canceled
|
the first Canceled (the second Canceled is discarded)
|
Canceled
|
Pending
|
the Canceled (the Pending is discarded)
|
Canceled
|
Failed
|
the Failed (the Canceled is discarded)
|
- Value parameters:
- blk
the block to execute and potentially retry
- delay
the amount of time to sleep before retrying
Retries the given block immediately (with no delay) if the Outcome
of executing
the block is Failed
.
Retries the given block immediately (with no delay) if the Outcome
of executing
the block is Failed
.
The behavior of this method is defined in the table below. The first row shows the main "retry" behavior: if
executing the block initially fails, and on retry it succeeds, the result is Canceled
. The purpose of this is
to deal with "flickering" tests by downgrading a failure that succeeds on retry
to a cancelation.
In the table below, if the “Retry Outcome
” has just a dash, the block is not retried.
Otherwise, the block is retried on the same thread, with no delay.
First Outcome | Retry Outcome | Result |
---|---|---|
Failed
|
Succeeded
|
Canceled (the Succeeded and Failed are
discarded; the exception from the Failed is the cause of the exception in the Canceled )
|
Succeeded
|
— |
Succeeded (no retry)
|
Pending
|
— |
Pending (no retry)
|
Canceled
|
— |
the Canceled (no retry)
|
Failed
|
Failed
|
the first Failed (the second Failed is discarded)
|
Failed
|
Pending
|
the Failed (the Pending is discarded)
|
Failed
|
Canceled
|
the Failed (the Canceled is discarded)
|
- Value parameters:
- blk
the block to execute and potentially retry
Retries the given block immediately with the given delay if the Outcome
of executing
the block is Failed
.
Retries the given block immediately with the given delay if the Outcome
of executing
the block is Failed
.
The behavior of this method is defined in the table below. The first row shows the main "retry" behavior: if
executing the block initially fails, and on retry it succeeds, the result is Canceled
. The purpose of this is
to deal with "flickering" tests by downgrading a failure that succeeds on retry
to a cancelation.
In the table below, if the “Retry Outcome
” has just a dash, the block is not retried.
Otherwise, the block is retried on the same thread, after the given delay.
First Outcome | Retry Outcome | Result |
---|---|---|
Failed
|
Succeeded
|
Canceled (the Succeeded and Failed are
discarded; the exception from the Failed is the cause of the exception in the Canceled )
|
Succeeded
|
— |
Succeeded (no retry)
|
Pending
|
— |
Pending (no retry)
|
Canceled
|
— |
the Canceled (no retry)
|
Failed
|
Failed
|
the first Failed (the second Failed is discarded)
|
Failed
|
Pending
|
the Failed (the Pending is discarded)
|
Failed
|
Canceled
|
the Failed (the Canceled is discarded)
|
- Value parameters:
- blk
the block to execute and potentially retry
- delay
the amount of time to sleep before retrying