[[Testing Framework Cheatsheet]]
= Testing

[partintro]

Elasticsearch uses jUnit for testing, it also uses randomness in the
tests, that can be set using a seed, the following is a cheatsheet of
options for running the tests for ES.

== Creating packages

To create a distribution without running the tests, simply run the
following:

-----------------------------
./gradlew assemble
-----------------------------

=== Running Elasticsearch from a checkout

In order to run Elasticsearch from source without building a package, you can
run it using Gradle:

-------------------------------------
./gradlew run
-------------------------------------

=== Test case filtering.

- `tests.class` is a class-filtering shell-like glob pattern,
- `tests.method` is a method-filtering glob pattern.

Run a single test case (variants)

----------------------------------------------------------
./gradlew test -Dtests.class=org.elasticsearch.package.ClassName
./gradlew test "-Dtests.class=*.ClassName"
----------------------------------------------------------

Run all tests in a package and sub-packages

----------------------------------------------------
./gradlew test "-Dtests.class=org.elasticsearch.package.*"
----------------------------------------------------

Run any test methods that contain 'esi' (like: ...r*esi*ze...).

-------------------------------
./gradlew test "-Dtests.method=*esi*"
-------------------------------

You can also filter tests by certain annotations ie:

  * `@Nightly` - tests that only run in nightly builds (disabled by default)
  * `@Backwards` - backwards compatibility tests (disabled by default)
  * `@AwaitsFix` - tests that are waiting for a bugfix (disabled by default)
  * `@BadApple` - tests that are known to fail randomly (disabled by default)

Those annotation names can be combined into a filter expression like:

------------------------------------------------
./gradlew test -Dtests.filter="@nightly and not @backwards"
------------------------------------------------

to run all nightly test but not the ones that are backwards tests. `tests.filter` supports
the boolean operators `and, or, not` and grouping ie:


---------------------------------------------------------------
./gradlew test -Dtests.filter="@nightly and not(@badapple or @backwards)"
---------------------------------------------------------------

=== Seed and repetitions.

Run with a given seed (seed is a hex-encoded long).

------------------------------
./gradlew test -Dtests.seed=DEADBEEF
------------------------------

=== Repeats _all_ tests of ClassName N times.

Every test repetition will have a different method seed
(derived from a single random master seed).

--------------------------------------------------
./gradlew test -Dtests.iters=N -Dtests.class=*.ClassName
--------------------------------------------------

=== Repeats _all_ tests of ClassName N times.

Every test repetition will have exactly the same master (0xdead) and
method-level (0xbeef) seed.

------------------------------------------------------------------------
./gradlew test -Dtests.iters=N -Dtests.class=*.ClassName -Dtests.seed=DEAD:BEEF
------------------------------------------------------------------------

=== Repeats a given test N times

(note the filters - individual test repetitions are given suffixes,
ie: testFoo[0], testFoo[1], etc... so using testmethod or tests.method
ending in a glob is necessary to ensure iterations are run).

-------------------------------------------------------------------------
./gradlew test -Dtests.iters=N -Dtests.class=*.ClassName -Dtests.method=mytest*
-------------------------------------------------------------------------

Repeats N times but skips any tests after the first failure or M initial failures.

-------------------------------------------------------------
./gradlew test -Dtests.iters=N -Dtests.failfast=true -Dtestcase=...
./gradlew test -Dtests.iters=N -Dtests.maxfailures=M -Dtestcase=...
-------------------------------------------------------------

=== Test groups.

Test groups can be enabled or disabled (true/false).

Default value provided below in [brackets].

------------------------------------------------------------------
./gradlew test -Dtests.nightly=[false]   - nightly test group (@Nightly)
./gradlew test -Dtests.weekly=[false]    - weekly tests (@Weekly)
./gradlew test -Dtests.awaitsfix=[false] - known issue (@AwaitsFix)
------------------------------------------------------------------

=== Load balancing and caches.

By default the tests run on up to 4 JVMs based on the number of cores. If you
want to explicitly specify the number of JVMs you can do so on the command
line:

----------------------------
./gradlew test -Dtests.jvms=8
----------------------------

Or in `~/.gradle/gradle.properties`:

----------------------------
systemProp.tests.jvms=8
----------------------------

Its difficult to pick the "right" number here. Hypercores don't count for CPU
intensive tests and you should leave some slack for JVM-interal threads like
the garbage collector. And you have to have enough RAM to handle each JVM.

=== Test compatibility.

It is possible to provide a version that allows to adapt the tests behaviour
to older features or bugs that have been changed or fixed in the meantime.

-----------------------------------------
./gradlew test -Dtests.compatibility=1.0.0
-----------------------------------------


=== Miscellaneous.

Run all tests without stopping on errors (inspect log files).

-----------------------------------------
./gradlew test -Dtests.haltonfailure=false
-----------------------------------------

Run more verbose output (slave JVM parameters, etc.).

----------------------
./gradlew test -verbose
----------------------

Change the default suite timeout to 5 seconds for all
tests (note the exclamation mark).

---------------------------------------
./gradlew test -Dtests.timeoutSuite=5000! ...
---------------------------------------

Change the logging level of ES (not Gradle)

--------------------------------
./gradlew test -Dtests.es.logger.level=DEBUG
--------------------------------

Print all the logging output from the test runs to the commandline
even if tests are passing.

------------------------------
./gradlew test -Dtests.output=always
------------------------------

Configure the heap size.

------------------------------
./gradlew test -Dtests.heap.size=512m
------------------------------

Pass arbitrary jvm arguments.

------------------------------
# specify heap dump path
./gradlew test -Dtests.jvm.argline="-XX:HeapDumpPath=/path/to/heapdumps"
# enable gc logging
./gradlew test -Dtests.jvm.argline="-verbose:gc"
# enable security debugging
./gradlew test -Dtests.jvm.argline="-Djava.security.debug=access,failure"
------------------------------

== Backwards Compatibility Tests

Running backwards compatibility tests is disabled by default since it
requires a release version of elasticsearch to be present on the test system.
To run backwards compatibilty tests untar or unzip a release and run the tests
with the following command:

---------------------------------------------------------------------------
./gradlew test -Dtests.filter="@backwards" -Dtests.bwc.version=x.y.z -Dtests.bwc.path=/path/to/elasticsearch -Dtests.security.manager=false
---------------------------------------------------------------------------

Note that backwards tests must be run with security manager disabled.
If the elasticsearch release is placed under `./backwards/elasticsearch-x.y.z` the path
can be omitted:

---------------------------------------------------------------------------
./gradlew test -Dtests.filter="@backwards" -Dtests.bwc.version=x.y.z -Dtests.security.manager=false
---------------------------------------------------------------------------

To setup the bwc test environment execute the following steps (provided you are
already in your elasticsearch clone):

---------------------------------------------------------------------------
$ mkdir backwards && cd backwards
$ curl -O https://download.elasticsearch.org/elasticsearch/elasticsearch/elasticsearch-1.2.1.tar.gz
$ tar -xzf elasticsearch-1.2.1.tar.gz
---------------------------------------------------------------------------

== Running verification tasks

To run all verification tasks, including static checks, unit tests, and integration tests:

---------------------------------------------------------------------------
./gradlew check
---------------------------------------------------------------------------

Note that this will also run the unit tests and precommit tasks first. If you want to just
run the integration tests (because you are debugging them):

---------------------------------------------------------------------------
./gradlew integTest
---------------------------------------------------------------------------

If you want to just run the precommit checks:

---------------------------------------------------------------------------
./gradlew precommit
---------------------------------------------------------------------------

== Testing the REST layer

The available integration tests make use of the java API to communicate with
the elasticsearch nodes, using the internal binary transport (port 9300 by
default).
The REST layer is tested through specific tests that are shared between all
the elasticsearch official clients and consist of YAML files that describe the
operations to be executed and the obtained results that need to be tested.

The YAML files support various operators defined in the link:/rest-api-spec/src/main/resources/rest-api-spec/test/README.asciidoc[rest-api-spec] and adhere to the link:/rest-api-spec/README.markdown[Elasticsearch REST API JSON specification]

The REST tests are run automatically when executing the "./gradlew check" command. To run only the
REST tests use the following command:

---------------------------------------------------------------------------
./gradlew :distribution:archives:integ-test-zip:integTest   \
  -Dtests.class="org.elasticsearch.test.rest.*Yaml*IT"
---------------------------------------------------------------------------

A specific test case can be run with

---------------------------------------------------------------------------
./gradlew :distribution:archives:integ-test-zip:integTest \
  -Dtests.class="org.elasticsearch.test.rest.*Yaml*IT" \
  -Dtests.method="test {p0=cat.shards/10_basic/Help}"
---------------------------------------------------------------------------

`*Yaml*IT` are the executable test classes that runs all the
yaml suites available within the `rest-api-spec` folder.

The REST tests support all the options provided by the randomized runner, plus the following:

* `tests.rest[true|false]`: determines whether the REST tests need to be run (default) or not.
* `tests.rest.suite`: comma separated paths of the test suites to be run
(by default loaded from /rest-api-spec/test). It is possible to run only a subset
of the tests providing a sub-folder or even a single yaml file (the default
/rest-api-spec/test prefix is optional when files are loaded from classpath)
e.g. -Dtests.rest.suite=index,get,create/10_with_id
* `tests.rest.blacklist`: comma separated globs that identify tests that are
blacklisted and need to be skipped
e.g. -Dtests.rest.blacklist=index/*/Index document,get/10_basic/*

Note that the REST tests, like all the integration tests, can be run against an external
cluster by specifying the `tests.cluster` property, which if present needs to contain a
comma separated list of nodes to connect to (e.g. localhost:9300). A transport client will
be created based on that and used for all the before|after test operations, and to extract
the http addresses of the nodes so that REST requests can be sent to them.

== Testing scripts

The simplest way to test scripts and the packaged distributions is to use
Vagrant. You can get started by following there five easy steps:

. Install Virtual Box and Vagrant.

. (Optional) Install vagrant-cachier to squeeze a bit more performance out of
the process:

--------------------------------------
vagrant plugin install vagrant-cachier
--------------------------------------

. Validate your installed dependencies:

-------------------------------------
./gradlew :qa:vagrant:vagrantCheckVersion
-------------------------------------

. Download and smoke test the VMs with `./gradlew vagrantSmokeTest` or
`./gradlew -Pvagrant.boxes=all vagrantSmokeTest`. The first time you run this it will
download the base images and provision the boxes and immediately quit. If you
you this again it'll skip the download step.

. Run the tests with `./gradlew packagingTest`. This will cause Gradle to build
the tar, zip, and deb packages and all the plugins. It will then run the tests
on ubuntu-1404 and centos-7. We chose those two distributions as the default
because they cover deb and rpm packaging and SyvVinit and systemd.

You can run on all the VMs by running `./gradlew -Pvagrant.boxes=all
packagingTest`. You can run a particular VM with a command like `./gradlew
-Pvagrant.boxes=oel-7 packagingTest`. See `./gradlew tasks` for a complete list
of available vagrant boxes for testing. It's important to know that if you
interrupt any of these Gradle commands then the boxes will remain running and
you'll have to terminate them with `./gradlew stop`.

All the regular vagrant commands should just work so you can get a shell in a
VM running trusty by running
`vagrant up ubuntu-1404 --provider virtualbox && vagrant ssh ubuntu-1404`.

These are the linux flavors the Vagrantfile currently supports:

* ubuntu-1404 aka trusty
* ubuntu-1604 aka xenial
* debian-8 aka jessie
* debian-9 aka stretch, the current debian stable distribution
* centos-6
* centos-7
* fedora-26
* fedora-27
* oel-6 aka Oracle Enterprise Linux 6
* oel-7 aka Oracle Enterprise Linux 7
* sles-12
* opensuse-42 aka Leap

We're missing the following from the support matrix because there aren't high
quality boxes available in vagrant atlas:

* sles-11

We're missing the following because our tests are very linux/bash centric:

* Windows Server 2012

It's important to think of VMs like cattle. If they become lame you just shoot
them and let vagrant reprovision them. Say you've hosed your precise VM:

----------------------------------------------------
vagrant ssh ubuntu-1404 -c 'sudo rm -rf /bin'; echo oops
----------------------------------------------------

All you've got to do to get another one is

----------------------------------------------
vagrant destroy -f ubuntu-1404 && vagrant up ubuntu-1404 --provider virtualbox
----------------------------------------------

The whole process takes a minute and a half on a modern laptop, two and a half
without vagrant-cachier.

Its possible that some downloads will fail and it'll be impossible to restart
them. This is a bug in vagrant. See the instructions here for how to work
around it:
https://github.com/mitchellh/vagrant/issues/4479

Some vagrant commands will work on all VMs at once:

------------------
vagrant halt
vagrant destroy -f
------------------

`vagrant up` would normally start all the VMs but we've prevented that because
that'd consume a ton of ram.

== Testing scripts more directly

In general its best to stick to testing in vagrant because the bats scripts are
destructive. When working with a single package it's generally faster to run its
tests in a tighter loop than Gradle provides. In one window:

--------------------------------
./gradlew :distribution:packages:rpm:assemble
--------------------------------

and in another window:

----------------------------------------------------
vagrant up centos-7 --provider virtualbox && vagrant ssh centos-7
cd $PACKAGING_ARCHIVES
sudo -E bats $BATS_TESTS/*rpm*.bats
----------------------------------------------------

If you wanted to retest all the release artifacts on a single VM you could:

-------------------------------------------------
./gradlew setupPackagingTest
cd qa/vagrant; vagrant up ubuntu-1404 --provider virtualbox && vagrant ssh ubuntu-1404
cd $PACKAGING_ARCHIVES
sudo -E bats $BATS_TESTS/*.bats
-------------------------------------------------

You can also use Gradle to prepare the test environment and then starts a single VM:

-------------------------------------------------
./gradlew vagrantFedora27#up
-------------------------------------------------

Or any of vagrantCentos6#up, vagrantCentos7#up, vagrantDebian8#up,
vagrantDebian9#up, vagrantFedora26#up, vagrantFedora27#up, vagrantOel6#up, vagrantOel7#up,
vagrantOpensuse42#up,vagrantSles12#up, vagrantUbuntu1404#up, vagrantUbuntu1604#up.

Once up, you can then connect to the VM using SSH from the elasticsearch directory:

-------------------------------------------------
vagrant ssh fedora-27
-------------------------------------------------

Or from another directory:

-------------------------------------------------
VAGRANT_CWD=/path/to/elasticsearch vagrant ssh fedora-27
-------------------------------------------------

Note: Starting vagrant VM outside of the elasticsearch folder requires to
indicates the folder that contains the Vagrantfile using the VAGRANT_CWD
environment variable.

== Testing backwards compatibility

Backwards compatibility tests exist to test upgrading from each supported version
to the current version. To run all backcompat tests use:

-------------------------------------------------
./gradlew bwcTest
-------------------------------------------------

A specific version can be tested as well. For example, to test backcompat with
version 5.3.2 run:

-------------------------------------------------
./gradlew v5.3.2#bwcTest
-------------------------------------------------

When running `./gradlew check`, some minimal backcompat checks are run. Which version
is tested depends on the branch. On master, this will test against the current
stable branch. On the stable branch, it will test against the latest release
branch. Finally, on a release branch, it will test against the most recent release.

=== BWC Testing against a specific remote/branch

Sometimes a backward compatibility change spans two versions. A common case is a new functionality
that needs a BWC bridge in an unreleased versioned of a release branch (for example, 5.x).
To test the changes, you can instruct Gradle to build the BWC version from a another remote/branch combination instead of
pulling the release branch from GitHub. You do so using the `tests.bwc.remote` and `tests.bwc.refspec.BRANCH` system properties:

-------------------------------------------------
./gradlew check -Dtests.bwc.remote=${remote} -Dtests.bwc.refspec.5.x=index_req_bwc_5.x
-------------------------------------------------

The branch needs to be available on the remote that the BWC makes of the
repository you run the tests from. Using the remote is a handy trick to make
sure that a branch is available and is up to date in the case of multiple runs.

Example:

Say you need to make a change to `master` and have a BWC layer in `5.x`. You
will need to:
. Create a branch called `index_req_change` off your remote `${remote}`. This
will contain your change.
. Create a branch called `index_req_bwc_5.x` off `5.x`. This will contain your bwc layer.
. Push both branches to your remote repository.
. Run the tests with `./gradlew check -Dtests.bwc.remote=${remote} -Dtests.bwc.refspec.5.x=index_req_bwc_5.x`.

== Skip fetching latest

For some BWC testing scenarios, you want to use the local clone of the
repository without fetching latest. For these use cases, you can set the system
property `tests.bwc.git_fetch_latest` to `false` and the BWC builds will skip
fetching the latest from the remote.

== Test coverage analysis

Generating test coverage reports for Elasticsearch is currently not possible through Gradle.
However, it _is_ possible to gain insight in code coverage using IntelliJ's built-in coverage 
analysis tool that can measure coverage upon executing specific tests. Eclipse may also be able
to do the same using the EclEmma plugin.

Test coverage reporting used to be possible with JaCoCo when Elasticsearch was using Maven
as its build system. Since the switch to Gradle though, this is no longer possible, seeing as
the code currently used to build Elasticsearch does not allow JaCoCo to recognize its tests.
For more information on this, see the discussion in https://github.com/elastic/elasticsearch/issues/28867[issue #28867].

== Launching and debugging from an IDE

If you want to run Elasticsearch from your IDE, the `./gradlew run` task
supports a remote debugging option:

---------------------------------------------------------------------------
./gradlew run --debug-jvm
---------------------------------------------------------------------------

== Debugging remotely from an IDE

If you want to run Elasticsearch and be able to remotely attach the process
for debugging purposes from your IDE, can start Elasticsearch using `ES_JAVA_OPTS`:

---------------------------------------------------------------------------
ES_JAVA_OPTS="-Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=4000,suspend=y" ./bin/elasticsearch
---------------------------------------------------------------------------

Read your IDE documentation for how to attach a debugger to a JVM process.

== Building with extra plugins
Additional plugins may be built alongside elasticsearch, where their
dependency on elasticsearch will be substituted with the local elasticsearch
build. To add your plugin, create a directory called elasticsearch-extra as
a sibling of elasticsearch. Checkout your plugin underneath elasticsearch-extra
and the build will automatically pick it up. You can verify the plugin is
included as part of the build by checking the projects of the build.

---------------------------------------------------------------------------
./gradlew projects
---------------------------------------------------------------------------