plainbox-job-units (7)


This page documents the syntax of the plainbox job units


A job unit is a smallest unit of testing that can be performed by either Checkbox or Plainbox. All jobs have an unique name. There are many types of jobs, some are fully automated others are fully manual. Some jobs are only an implementation detail and a part of the internal architecture of Checkbox.

File format and location

Jobs are expressed as sections in text files that conform somewhat to the rfc822 specification format. Our variant of the format is described in rfc822. Each record defines a single job.

Job Fields

Following fields may be used by the job unit:

(mandatory) - A name for the job. Should be unique, an error will be generated if there are duplicates. Should contain characters in [a-z0-9/-]. This field used to be called name. That name is now deprecated. For backwards compatibility it is still recognized and used if id is missing.
(mandatory) - A human readable name for the job. This value is available for translation into other languages. It is used when listing jobs. It must be one line long, ideally it should be short (50-70 characters max).

(mandatory) - For historical reasons it’s called “plugin” but it’s better thought of as describing the “type” of job. The allowed types are:

manual:jobs that require the user to perform an action and then decide on the test’s outcome.
shell:jobs that run without user intervention and automatically set the test’s outcome.
user-interact:jobs that require the user to perform an interaction, after which the outcome is automatically set.
 jobs that require the user to perform an interaction, run a command after which the user is asked to decide on the test’s outcome. This is essentially a manual job with a command.
attachment:jobs whose command output will be attached to the test report or submission.
resource:A job whose command output results in a set of rfc822 records, containing key/value pairs, and that can be used in other jobs’ requires expressions.
qml:jobs that run a custom QML payload within a test shell (QML application or a generic, minimalistic QML test shell) using test API described in CEP-5


The following plugin names are deprecated:

user-verify:jobs that automatically perform an action or test and then request the user to decide on the test’s outcome. This was deprecated because the user had no chance to read instructions prior to the test. Use user-interact-verify instead; that will present instructions, ask the user to click a button before running the command, and finally prompt for outcome assessment.

(optional). If specified, the job will only run if the conditions expressed in this field are met.

Conditions are of the form <resource>.<key> <comparison-operator> 'value' (and|or) ... . Comparison operators can be ==, != and in. Values to compare to can be scalars or (in the case of the in operator) arrays or tuples. The not in operator is explicitly unsupported.

Requirements can be logically chained with or and and operators. They can also be placed in multiple lines, respecting the rfc822 multi-line syntax, in which case all requirements must be met for the job to run ( and ed).

The Plainbox resource program evaluator is extensively documented, to see a detailed description including rationale and implementation of Checkbox “legacy” compatibility, see

(optional). If specified, the job will only run if all the listed jobs have run and passed. Multiple job names, separated by spaces, can be specified.

(optional). If specified, the job will only run if all the listed jobs have run (regardless of the outcome). Multiple job names, separated by spaces, can be specified.

This feature is available since plainbox 0.24.


(optional). A command can be provided, to be executed under specific circumstances. For manual, user-interact and user-verify jobs, the command will be executed when the user presses a “test” button present in the user interface. For shell jobs, the command will be executed unconditionally as soon as the job is started. In both cases the exit code from the command (0 for success, !0 for failure) will be used to set the test’s outcome. For manual, user-interact and user-verify jobs, the user can override the command’s outcome. The command will be run using the default system shell. If a specific shell is needed it should be instantiated in the command. A multi-line command or shell script can be used with the usual multi-line syntax.

Note that a shell job without a command will do nothing.


(mandatory). Provides a textual description for the job. This is mostly to aid people reading job descriptions in figuring out what a job does.

The description field, however, is used specially in manual, user-interact and user-verify jobs. For these jobs, the description will be shown in the user interface, and in these cases it’s expected to contain instructions for the user to follow, as well as criteria for him to decide whether the job passes or fails. For these types of jobs, the description needs to contain a few sub-fields, in order:

PURPOSE:This indicates the purpose or intent of the test.
STEPS:A numbered list of steps for the user to follow.
INFO:(optional). Additional information about the test. This is commonly used to present command output for the user to validate. For this purpose, the $output substitution variable can be used (actually, it can be used anywhere in the description). If present, it will be replaced by the standard output generated from running the job’s command (commonly when the user presses the “Test” button).
VERIFICATION:A question for the user to answer, deciding whether the test passes or fails. The question should be phrased in such a way that an answer of Yes means the test passed, and an answer of No means it failed.


since version 0.17 fields: purpose, steps and verification should be used instead of description.

This test will check that internal speakers work correctly
  1. Make sure that no external speakers or headphones are connected When testing a desktop, you can skip this test if there is no internal speaker, we will test the external output later
  2. Click the Test button to play a brief tone on your audio device
Did you hear a tone?
This test will check that internal speakers work correctly
  1. Make sure that no external speakers or headphones are connected When testing a desktop, you can skip this test if there is no internal speaker, we will test the external output later
  2. Click the Test button to play a brief tone on your audio device
Did you hear a tone?

Note that if client code references the description field, plainbox will combine purpose, steps and verification fields into one and use the result

(optional). Purpose field is used in tests requiring human interaction as an information about what a given test is supposed to do. User interfaces should display content of this field prior to test execution. This field may be omitted if the summary field is supplied. Note that this field is applicable only for human interaction jobs.
(optional). Steps field depicts actions that user should perform as a part of job execution. User interfaces should display the content of this field upon starting the test. Note that this field is applicable only for jobs requiring the user to perform some actions.
(optional). Verification field is used to inform the user how they can resolve a given job outcome. Note that this field is applicable only for jobs the result of which is determined by the user.
(optional). If specified, the job will be run as the user specified here. This is most commonly used to run jobs as the superuser (root).
(optional). If specified, the listed environment variables (separated by spaces) will be taken from the invoking environment (i.e. the one Checkbox is run under) and set to that value on the job execution environment (i.e. the one the job will run under). Note that only the variable names should be listed, not the values, which will be taken from the existing environment. This only makes sense for jobs that also have the user attribute. This key provides a mechanism to account for security policies in sudo and pkexec, which provide a sanitized execution environment, with the downside that useful configuration specified in environment variables may be lost in the process.

(optional) This field contains metadata about how long the job is expected to run for, as a positive float value indicating the estimated job duration in seconds.

Since plainbox version 0.24 this field can be expressed in two formats. The old format, a floating point number of seconds is somewhat difficult to read for larger values. To avoid mistakes test designers can use the second format with separate sections for number of hours, minutes and seconds. The format, as regular expression, is (\d+h)?[: ]*(\d+m?)[: ]*(\d+s)?. The regular expression expresses an optional number of hours, followed by the h character, followed by any number of spaces or : characters, followed by an optional number of minutes, followed by the m character, again followed by any number of spaces or : characters, followed by the number of seconds, ultimately followed by the s character.

The values can no longer be fractional (you cannot say 2.5m you need to say 2m 30s). We feel that sub-second granularity does is too unpredictable to be useful so that will not be supported in the future.


(optional) This fields contains list of flags separated by spaces or commas that might induce plainbox to run the job in particular way. Currently, following flags are inspected by plainbox:

This flag makes plainbox carry locale settings to the job’s command. If this flag is not set, plainbox will neuter locale settings. Attach this flag to all job definitions with commands that use translations .
This flag makes plainbox run jobs’ commands in windows-specific manner. Attach this flag to jobs that are run on Windows OS.
This flag makes plainbox suspend execution after job’s command is run. This prevents scenario where plainbox continued to operate (writing session data to disk and so on), while other process kills it (leaving plainbox session in unwanted/undefined state). Attach this flag to jobs that cause killing of plainbox process during their operation. E.g. run shutdown, reboot, etc.
Use this flag to make entering comment mandatory, when the user manually fails the job.
This flag makes plainbox silently ignore (and not log) any files left over by the execution of the command associated with a job. This flag is useful for jobs that don’t bother with maintenance of temporary directories and just want to rely on the one already created by plainbox.

This flag makes plainbox disable certain validation advice and have some sesible defaults for automated test cases. This simiplification is meant to cut the boiler plate on jobs that are closer to unit tests than elaborate manual interactions.

In practice the following changes are in effect when this flag is set:

  • the plugin field defaults to shell
  • the description field is entirely optional
  • the estimated_duration field is entirely optional
  • the preserve-locale flag is entirely optional

A minimal job using the simple flag looks as follows:

id: foo
command: echo "Jobs are simple!"
flags: simple
This flag makes plainbox run the job command in the current working directory without creating a temp folder (and running the command from this temp folder). Sometimes needed on snappy (See
This flag makes plainbox fail the job if one of the resource requirements evaluates to False.
also-after-suspend: See siblings below.

also-after-suspend-manual: See siblings below.

Additional flags may be present in job definition; they are ignored.

Saves the output of a resource job in the system, so the next time the session is started recorded output is used making the session bootstrap faster.

This flag has no effect on jobs other than resource.


(optional) This field creates copies of the current job definition but using a dictionary of overridden fields. The intend is to reduce the amount of job definitions when only a few changes are required to make a job. For example we often run the same test after suspend. In that case only a new id, a new job dependency (e.g suspend/advanced) and an updated summary are required. Other possible uses of this feature are tests creation for a fixed/limited list of external ports (USB port 1, USB port 2). Useful when such enumerations cannot be computed from a resource job. This field is interpreted as a JSON blob, an array of dictionaries.

A minimal job using the siblings field looks as follows:

id: foo
_summary: foo foo foo
command: echo "Hello world"
flags: simple
_siblings: [
    { "id": "foo-after-suspend",
      "_summary": "foo foo foo after suspend",
      "depends": suspend/advanced}

Another example creating two more jobs in order to cover a total of 3 external USB ports:

id: usb_test_port1
_summary: usb stress test_(port 1)
flags: simple
_siblings: [
    { "id": "usb_test_port2",
      "_summary": "usb stress test_(port 2)"},
    { "id": "usb_test_port3",
      "_summary": "usb stress test_(port 3)"},

For convenience two flags can be set (also-after-suspend and also-after-suspend-manual) to create siblings with predefined settings to add “after suspend” jobs.

Given the base job:

_summary: bar
flags: also-after-suspend also-after-suspend-manual

The also-after-suspend flag is a shortcut to create the following job:

id: after-suspend-foo
_summary: bar after suspend (S3)
depends: com.canonical.certification::suspend/suspend_advanced_auto

also-after-suspend-manual is a shortcut to create the following job:

id: after-suspend-manual-foo
_summary: bar after suspend (S3)
depends: com.canonical.certification::suspend/suspend_advanced


The curly braces used in this field have to be escaped when used in a template job (python format, Jinja2 templates do not have this issue). The syntax for templates is:

_siblings: [
    {{ "id": "bar-after-suspend_{interface}",
      "_summary": "bar after suspend",
      "depends": suspend/advanced}}

(optional) This field lists all the resource jobs that will have to be imported from other namespaces. This enables jobs to use resources from other namespaces. You can use the “as …” syntax to import jobs that have dashes, slashes or other characters that would make them invalid as identifiers and give them a correct identifier name. E.g.:

imports: from com.canonical.certification import cpuinfo
requires: 'armhf' in cpuinfo.platform

imports: from com.canonical.certification import cpu-01-info as cpu01
requires: 'avx2' in cpu01.other

The syntax of each imports line is:

               | "from" <NAMESPACE> "import" <PARTIAL_ID> AS <IDENTIFIER>

Extension of the job format

The Checkbox job format can be considered “extensible”, in that additional keys can be added to existing jobs to contain additional data that may be needed.

In order for these extra fields to be exposed through the API (i.e. as properties of JobDefinition instances), they need to be declared as properties in (plainbox.impl.job). This is a good place to document, via a docstring, what the field is for and how to interpret it.

Implementation note: if additional fields are added, Checkbox needs to be also told about them, the reason is that Checkbox does perform validation of the job descriptions, ensuring they contain only known fields and that fields contain expected data types. The jobs_info plugin contains the job schema declaration and can be consulted to verify the known fields, whether they are optional or mandatory, and the type of data they’re expected to contain.

Also, Checkbox validates that fields contain data of a specific type, so care must be taken not to simply change contents of fields if Checkbox compatibility of jobs is desired.

Plainbox does this validation on a per-accessor basis, so data in each field must make sense as defined by that field’s accessor. There is no need, however, to declare field type beforehand.

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