LAVA Test Shell¶
The lava_test_shell
action provides a way to employ a more black-box style
testing appoach with the target device. The test definition format is quite
flexible and allows for some interesting things.
Quick start¶
A minimal test definition looks like this:
metadata:
name: passfail
format: "Lava-Test-Shell Test Definition 1.0"
description: "A simple passfail test for demo."
os:
- ubuntu
- openembedded
devices:
- origen
- panda
environment:
- lava-test-shell
params:
TEST_1: pass
run:
steps:
- echo "test-1: $TEST_1"
- echo "test-2: fail"
parse:
pattern: "(?P<test_case_id>.*-*):\\s+(?P<result>(pass|fail))"
Note
The parse pattern has similar quoting rules as Python, so \s must be escaped as \\s and similar.
However, the parameters such as os, devices, environment are optional in the metadata section. On the other hand parameters such as name, format, description are mandatory in the metadata section.
Versioned test definitions¶
If your test definition is not part of a bzr or git repository then it is mandatory to have a version parameter in metadata section. The following example shows how a test definition metadata section will look like for a test definition which is not part of bzr or git repository:
metadata:
name: passfail
format: "Lava-Test-Shell Test Definition 1.0"
version: "1.0"
description: "A simple passfail test for demo."
os:
- ubuntu
- openembedded
devices:
- origen
- panda
environment:
- lava-test-shell
Note
Only if the test definition is referred from a URL the version parameter should be explicit.
How a lava test shell is run¶
A lava-test-shell is run by:
compiling the above test defintion into a shell script.
Note
This shell script will have a
set -e
at the top, so a failing step will abort the entire test run. If you need to specify a step that might fail, but should not cause the run to be aborted, make sure you finish the command with|| true
.copying this script onto the device and arranging for it to be run when the device boots
booting the device and letting the test run
retrieving the output from the device and turning it into a test result bundle
run subsequent test definitions, if any. See Minimise the number of reboots within a single test.
Writing a test for lava-test-shell¶
For the majority of cases, the above approach is the easiest thing to do: write shell code that outputs “test-case-id: result” for each test case you are interested in. See the Test Developer Guide:
The advantage of the parsing approach is that it means your test is
easy to work on independently from LAVA: simply write a script that
produces the right sort of output, and then provide a very small
amount of glue to wire it up in LAVA. However, when you need it,
there is also a more powerful, LAVA-specific, way of writing tests.
When a test runs, $PATH
is arranged so that some LAVA-specific
utilities are available:
lava-test-case
lava-test-case-attach
lava-test-run-attach
lava-background-process-start
lava-background-process-stop
lava-test-case¶
lava-test-case records the results of a single test case. For example:
steps:
- "lava-test-case simpletestcase --result pass"
- "lava-test-case fail-test --shell false"
It has two forms. One takes arguments to describe the outcome of the test case and the other takes the shell command to run – the exit code of this shell command is used to produce the test result.
Both forms take the name of the testcase as the first argument.
Specifying results directly¶
The first form takes these additional arguments:
--result $RESULT
: $RESULT should be one of pass/fail/skip/unknown--measurement $MEASUREMENT
: A numerical measurement associated with the test result--units $UNITS
: The units of $MEASUREMENT
--result
must always be specified. For example:
run:
steps:
- "lava-test-case simpletestcase --result pass"
- "lava-test-case bottle-count --result pass --measurement 99 --units bottles"
If --measurement
is used, --units
must also be specified, even
if the unit is just a count.
The most useful way to produce output for lava-test-case result
is
Writing custom scripts to support tests which allow preparation of LAVA results from other
sources, complete with measurements. This involves calling lava-test-case
from scripts executed by the YAML file:
#!/usr/bin/env python
from subprocess import call
def test_case():
"""
Calculate something based on a test
and return the data
"""
return {"name": "test-rate", "result": "pass",
"units": "Mb/s", "measurement": 4.23}
def main():
data = test_case()
call(
['lava-test-case',
data['name'],
'--result', data['result'],
'--measurement', data['measurement'],
'--units', data['units']])
return 0
if __name__ == '__main__':
main()
The custom scripts themselves can be called from a lava-test-case
using the --shell
command to test whether failures from the tests
caused a subsequent failure in the custom script.
Using the exit status of a command¶
The second form of lava-test-case
is indicated by the --shell
argument, for example:
run:
steps:
- "lava-test-case fail-test --shell false"
- "lava-test-case pass-test --shell true"
The result of a shell
call will only be recorded as a pass or fail,
dependent on the exit code of the command. The output of the command
can, however, be parsed as a separate result if the command produces
output suitable for the parser in the YAML:
run:
steps:
- lava-test-case echo2 --shell echo "test2b:" "fail"
parse:
pattern: "(?P<test_case_id>.*-*):\\s+(?P<result>(pass|fail))"
This example generates two test results to indicate that the shell command executed correctly but that the result of that execution was a fail:
#. **echo2** - pass
#. **test2b** - fail
lava-test-case-attach¶
Caution
lava-test-case-attach
is retained with the
dispatcher refactoring but the effect of the script needs
consideration by the test writer. See Handling test attachments.
This attaches a file to a test result with a particular ID, for example:
steps:
- "echo content > file.txt"
- "lava-test-case test-attach --result pass"
- "lava-test-case-attach test-attach file.txt text/plain"
The arguments are:
- test case id
- the file to attach
- (optional) the MIME type of the file (if no MIME type is passed, a guess is made based on the filename)
lava-test-run-attach¶
Caution
lava-test-run-attach
is retained with the
dispatcher refactoring but the effect of the script needs
consideration by the test writer. See Handling test attachments.
This attaches a file to the overall test run that lava-test-shell is currently executing, for example:
steps:
- "echo content > file.txt"
- "lava-test-run-attach file.txt text/plain"
The arguments are:
- the file to attach
- (optional) the MIME type of the file (if no MIME type is passed, a guess is made based on the filename)
lava-background-process-start¶
This starts process in the background. For example:
steps:
- lava-background-process-start MEM --cmd "free -m | grep Mem | awk '{print $3}' >> /tmp/memusage"
- lava-background-process-start CPU --cmd "grep 'cpu ' /proc/stat"
- uname -a
- lava-background-process-stop CPU
- lava-background-process-stop MEM --attach /tmp/memusage text/plain --attach /proc/meminfo application/octet-stream
The arguments are:
- Name that is used to identify the process later in lava-background-process-stop
- The process to be run in the background
lava-background-process-stop¶
This stops the process previously started in the background. User can attach files to the test run if there is a need.
For example:
steps:
- lava-background-process-start MEM --cmd "free -m | grep Mem | awk '{print $3}' >> /tmp/memusage"
- lava-background-process-start CPU --cmd "grep 'cpu ' /proc/stat"
- uname -a
- lava-background-process-stop CPU
- lava-background-process-stop MEM --attach /tmp/memusage text/plain --attach /proc/meminfo application/octet-stream
The arguments are:
- Name that was specified in lava-background-process-start
- (optional) Indicate if you want to attach file(s) the test run with specified mime type. See Handling test attachments.
Handling test attachments¶
The deprecated dispatcher support for test attachments depends on the deprecated bundle and bundle stream support - the scripts available in lava-test shell do not actually attach the requested files, just copy the files to a hard-coded directory where the bundle processing code expects to find data to put into the bundle. This relies on the device being booted into an environment with a working network connection - what was called the master image.
In the pipeline support, master images and bundles have been removed. This puts the handling of attachments into the control of the test writer. An equivalent method would be to simply add another deploy and boot action to get into an environment where the network connection is known to work, however the eventual location of the file needs to be managed by the test writer. An alternative method for text based data is simply to output the contents into the log file. (Individual parts of the log file can be downloaded separately.)
Handling Dependencies (Debian)¶
If your test requires some packages to be installed before its run it can
express that in the install
section with:
install:
deps:
- linux-libc-dev
- build-essential
Installation of packages can be skipped by specifying "skip_install": "deps"
parameter in the JSON job definition Available parameters.
Adding Git/BZR Repositories¶
If your test needs code from a shared repository, the action can clone this data on your behalf with:
install:
bzr-repos:
- lp:lava-test
git-repos:
- git://git.linaro.org/people/davelong/lt_ti_lava.git
run:
steps:
- cd lt_ti_lava
- echo "now in the git cloned directory"
This repository information will also be added to resulting bundle’s software context when the results are submitted to the LAVA dashboard.
Cloning of the repositories can be skipped by specifying "skip_install": "repos"
parameter in the JSON job definition Available parameters.
git-repos¶
The git-repos section shown above can be customized as follows:
install:
git-repos:
- url: https://git.linaro.org/lava/lava-dispatcher.git
skip_by_default: False
- url: https://git.linaro.org/lava/lava-dispatcher.git
destination: lava-d-r
branch: release
- url: https://git.linaro.org/lava/lava-dispatcher.git
destination: lava-d-s
branch: staging
- url is the git repository URL.
- skip_by_default (optional) accepts a True or False. Repositories can be skipped by default in the YAML and enabled for particular jobs in the JSON. Similarly, repositories can be set to install by default and be disabled for particular jobs in the JSON.
- destination (optional) is the directory in which the git repository given in url should be cloned.
- branch (optional) is the branch within the git repository given in url that should be cloned.
All the above parameters within the git-repos section could be controlled from the JSON job file. See the following JSON job definition and YAML test definition to get an understanding of how it works.
Install Steps¶
Before the test shell code is executed, it will optionally do some install work if needed. For example if you needed to build some code from a git repo you could do:
install:
git-repos:
- git://git.linaro.org/people/davelong/lt_ti_lava.git
steps:
- cd lt_ti_lava
- make
Running installation steps can be skipped by specifying "skip_install": "steps"
parameter in the JSON job definition Available parameters.
Note
The repo steps are done in the dispatcher itself. The install steps are run directly on the target.
Advanced Parsing¶
You may need to incorporate an existing test that doesn’t output results in
in the required pass
/fail
/skip
/unknown
format required by
LAVA. The parse section has a fixup mechanism that can help:
parse:
pattern: "(?P<test_case_id>.*-*)\\s+:\\s+(?P<result>(PASS|FAIL))"
fixupdict:
PASS: pass
FAIL: fail
Note
Pattern can be double-quoted or single quoted. If it’s double-quoted, special characters need to be escaped. Otherwise, no escaping is necessary.
Single quote example:
parse:
pattern: '(?P<test_case_id>.*-*)\s+:\s+(?P<result>(PASS|FAIL))'
fixupdict:
PASS: pass
FAIL: fail
Adding dependent test cases¶
If your test depends on other tests to be executed before you run the current test, the following definition will help:
test-case-deps:
- git-repo: git://git.linaro.org/qa/test-definitions.git
testdef: common/passfail.yaml
- bzr-repo: lp:~stylesen/lava-dispatcher/sampletestdefs-bzr
testdef: testdef.yaml
- url: http://people.linaro.org/~senthil.kumaran/deps_sample.yaml
The test cases specified within ‘test-case-deps’ section will be fetched from the given repositories or url and then executed in the same specified order. Following are valid repository or url source keys that can be specified inside the ‘test-case-deps’ section:
1. git-repo
2. bzr-repo
3. tar-repo
4. url
Note
For keys such as git-repo, bzr-repo and tar-repo testdef name within this repo must be specfied with testdef parameter else lavatest.yaml is the name assumed.
Caution
lava-test-shell does not take care of circular dependencies
within these test definitions. If a test definition say tc1.yaml
is specified within test-case-deps
section of tc-main.yaml
and in
tc1.yaml
there is a test-case-deps
section which refers to
tc-main.yaml
then this will create a circular dependency.
lava-test-shell
will fetch the test definitions tc1.yaml
and
tc-main.yaml
indefinitely and fail after timeout. The log
for such cases would show many attempts at loading test definition...
.