OpenSearch uses [jUnit](https://junit.org/junit5/) 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 OpenSearch.
- [Requirements](#requirements)
- [Creating packages](#creating-packages)
- [Running OpenSearch from a checkout](#running-opensearch-from-a-checkout)
- [Launching and debugging from an IDE](#launching-and-debugging-from-an-ide)
**NOTE:** If you have imported the project into IntelliJ according to the instructions in [DEVELOPER_GUIDE.md](DEVELOPER_GUIDE.md#importing-the-project-into-intellij-idea), then a debug run configuration named **Debug OpenSearch** will be created for you and configured appropriately.
This will instruct all JVMs (including any that run cli tools such as creating the keyring or adding users) to suspend and initiate a debug connection on port incrementing from `5005`. As such, the IDE needs to be instructed to listen for connections on this port. Since we might run multiple JVMs as part of configuring and starting the cluster, it's recommended to configure the IDE to initiate multiple listening attempts. In case of IntelliJ, this option is called "Auto restart" and needs to be checked. In case of Eclipse, "Connection limit" setting needs to be configured with a greater value (ie 10 or more).
- In order to start a node with a different max heap space add: `-Dtests.heap.size=4G`
- In order to disable assertions add: `-Dtests.asserts=false`
- In order to use a custom data directory: `--data-dir=/tmp/foo`
- In order to preserve data in between executions: `--preserve-data`
- In order to remotely attach a debugger to the process: `--debug-jvm`
- In order to set a different keystore password: `--keystore-password yourpassword`
- In order to set an OpenSearch setting, provide a setting with the following prefix: `-Dtests.opensearch.`
## 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.opensearch.package.ClassName
./gradlew test "-Dtests.class=*.ClassName"
Run all tests in a package and its sub-packages
./gradlew test "-Dtests.class=org.opensearch.package.*"
Run any test methods that contain *esi* (e.g.: .r*esi*ze.)
./gradlew test "-Dtests.method=*esi*"
Run all tests that are waiting for a bugfix (disabled by default)
./gradlew test -Dtests.filter=@awaitsfix
## 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 that individual test repetitions are passed suffixes, such as: `testFoo[0]`, `testFoo[1]`, etc. Thus 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.awaitsfix=[false] - known issue (@AwaitsFix)
By default, the tests run on multiple processes using all the available cores on all available CPUs. Not including hyper-threading. If you want to explicitly specify the number of JVMs you can do so on the command line:
It's difficult to pick the "right" number here. Hypercores don’t count for CPU intensive tests, and you should leave some slack for JVM-internal threads like the garbage collector. And you have to have enough RAM to handle each JVM.
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.
Run all tests without stopping on errors (inspect log files).
./gradlew test -Dtests.haltonfailure=false
Run more verbose output (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 OpenSearch (not Gradle)
./gradlew test -Dtests.opensearch.logger.level=DEBUG
Print all the logging output from the test runs to the commandline even if tests are passing.
./gradlew test -Dtests.output=true
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"
# 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 in memory cluster integration tests (because you are debugging them):
Some of these checks will require `docker-compose` installed for bringing up test fixtures. If it’s not present those checks will be skipped automatically.
# Testing the REST layer
The REST layer is tested through specific tests that are executed against a cluster that is configured and initialized via Gradle. The tests themselves can be written in either Java or with a YAML based DSL.
YAML based REST tests should be preferred since these are shared between clients. The YAML based tests describe the operations to be executed, and the obtained results that need to be tested.
The YAML tests support various operators defined in the [rest-api-spec](/rest-api-spec/src/main/resources/rest-api-spec/test/README.md) and adhere to the [OpenSearch REST API JSON specification](/rest-api-spec/README.md). In order to run the YAML tests, the relevant API specification needs to be on the test classpath. Any gradle project that has support for REST tests will get the primary API on it’s class path. However, to better support Gradle incremental builds, it is recommended to explicitly declare which parts of the API the tests depend upon.
The REST tests are run automatically when executing the "./gradlew check" command. To run only the YAML REST tests use the following command (modules and plugins may also include YAML REST tests):
./gradlew :rest-api-spec:yamlRestTest
A specific test case can be run with the following command:
The YAML REST tests support all the options provided by the randomized runner, plus the following:
-`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/**`
Java REST tests can be run with the "javaRestTest" task.
yamlRestTest’s and javaRestTest’s are easy to identify, since they are found in a respective source directory. However, there are some more specialized REST tests that use custom task names. These are usually found in "qa" projects commonly use the "integTest" task.
If in doubt about which command to use, simply run <gradle path>:check
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).
The packaging tests use Vagrant virtual machines or cloud instances to verify that installing and running OpenSearch distributions works correctly on supported operating systems. These tests should really only be run on ephemeral systems because they’re destructive; that is, these tests install and remove packages and freely modify system settings, so you will probably regret it if you execute them on your development machine.
When you run a packaging test, Gradle will set up the target VM and mount your repository directory in the VM. Once this is done, a Gradle task will issue a Vagrant command to run a **nested** Gradle task on the VM. This nested Gradle runs the actual "destructive" test classes.
1. Install Virtual Box and Vagrant.
2. (Optional) Install [vagrant-cachier](https://github.com/fgrehm/vagrant-cachier) to squeeze a bit more performance out of the process (Note: as of 2021, vagrant-cachier is unmaintained):
To run only the OS tests that are written in Java, run `.gradlew distroTest`, will cause Gradle to build the tar, zip, and deb packages and all the plugins. It will then run the tests on every available system. This will take a very long time.
Fortunately, the various systems under test have their own Gradle tasks under `qa/os`. To find out what packaging combinations can be tested on a system, run the `tasks` task. For example:
Note that if you interrupt Gradle in the middle of running these tasks, any boxes started will remain running, and you’ll have to stop them manually with `./gradlew --stop` or `vagrant halt`.
All the regular vagrant commands should just work, so you can get a shell in a VM running trusty by running `vagrant up ubuntu-1604 --provider virtualbox && vagrant ssh ubuntu-1604`.
The packaging tests also support Windows Server 2012R2 and Windows Server 2016. Unfortunately we’re not able to provide boxes for them in open source use because of licensing issues. Any Virtualbox image that has WinRM and Powershell enabled for remote users should work.
Testing on Windows requires the [vagrant-winrm](https://github.com/criteo/vagrant-winrm) plugin.
vagrant plugin install vagrant-winrm
Specify the image IDs of the Windows boxes to gradle with the following project properties. They can be set in `~/.gradle/gradle.properties` such as
vagrant.windows-2012r2.id=my-image-id
vagrant.windows-2016.id=another-image-id
or passed on the command line such as `-Pvagrant.windows-2012r2.id=my-image-id` or `-Pvagrant.windows-2016=another-image-id`
These properties are required for Windows support in all gradle tasks that handle packaging tests. Either or both may be specified.
If you’re running vagrant commands outside of gradle, specify the Windows boxes with the environment variables.
-`VAGRANT_WINDOWS_2012R2_BOX`
-`VAGRANT_WINDOWS_2016_BOX`
## Testing VMs are disposable
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:
Because our packaging tests are capable of testing many combinations of OS (e.g., Windows, Linux, etc.), package type (e.g., zip file, RPM, etc.) and so forth, it’s faster to develop against smaller subsets of the tests. For example, to run tests for the default archive distribution on Fedora 28:
The test can be run for any versions which the current version will be compatible with. Tests are run for released versions download the distributions from the artifact repository, see [DistributionDownloadPlugin](./buildSrc/src/main/java/org/opensearch/gradle/DistributionDownloadPlugin.java) for the repository location. Tests are run for versions that are not yet released automatically check out the branch and build from source to get the distributions, see [BwcVersions](./buildSrc/src/main/java/org/opensearch/gradle/BwcVersions.java) and [distribution/bwc/build.gradle](./distribution/bwc/build.gradle) for more information.
The minimum JDK versions for runtime and compiling need to be installed, and environment variables `JAVAx_HOME`, such as `JAVA8_HOME`, pointing to the JDK installations are required to run the tests against unreleased versions, since the distributions are created by building from source. The required JDK versions for each branch are located at [.ci/java-versions.properties](.ci/java-versions.properties), see [BwcSetupExtension](./buildSrc/src/main/java/org/opensearch/gradle/internal/BwcSetupExtension.java) for more information.
When running `./gradlew check`, minimal bwc checks are also run against compatible versions that are not yet released.
## 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 `bwc.remote` and `bwc.refspec.BRANCH` system properties:
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 `${remote}`. This will contain your change. . Create a branch called `index_req_bwc_5.x` off `5.x`. This will contain your bwc layer. . Push both branches to your remote repository. . Run the tests with `./gradlew check -Dbwc.remote=${remote} -Dbwc.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.
# How to write good tests?
## Base classes for test cases
There are multiple base classes for tests:
-**`OpenSearchTestCase`**: The base class of all tests. It is typically extended directly by unit tests.
-**`OpenSearchSingleNodeTestCase`**: This test case sets up a cluster that has a single node.
-**`OpenSearchIntegTestCase`**: An integration test case that creates a cluster that might have multiple nodes.
-**`OpenSearchRestTestCase`**: An integration tests that interacts with an external cluster via the REST API. This is used for Java based REST tests.
-**`OpenSearchClientYamlSuiteTestCase`** : A subclass of `OpenSearchRestTestCase` used to run YAML based REST tests.
## Good practices
### What kind of tests should I write?
Unit tests are the preferred way to test some functionality: most of the time they are simpler to understand, more likely to reproduce, and unlikely to be affected by changes that are unrelated to the piece of functionality that is being tested.
The reason why `OpenSearchSingleNodeTestCase` exists is that all our components used to be very hard to set up in isolation, which had led us to having a number of integration tests but close to no unit tests. `OpenSearchSingleNodeTestCase` is a workaround for this issue which provides an easy way to spin up a node and get access to components that are hard to instantiate like `IndicesService`. Whenever practical, you should prefer unit tests.
Many tests extend `OpenSearchIntegTestCase`, mostly because this is how most tests used to work in the early days of Elasticsearch. However, the complexity of these tests tends to make them hard to debug. Whenever the functionality that is being tested isn’t intimately dependent on how OpenSearch behaves as a cluster, it is recommended to write unit tests or REST tests instead.
Unfortunately, a large part of our code base is still hard to unit test. Sometimes because some classes have lots of dependencies that make them hard to instantiate. Sometimes because API contracts make tests hard to write. Code refactors that make functionality easier to unit test are encouraged.
In general, randomization should be used for parameters that are not expected to affect the behavior of the functionality that is being tested. For instance the number of shards should not impact `date_histogram` aggregations, and the choice of the `store` type (`niofs` vs `mmapfs`) does not affect the results of a query. Such randomization helps improve confidence that we are not relying on implementation details of one component or specifics of some setup.
However, it should not be used for coverage. For instance if you are testing a piece of functionality that enters different code paths depending on whether the index has 1 shards or 2+ shards, then we shouldn’t just test against an index with a random number of shards: there should be one test for the 1-shard case, and another test for the 2+ shards case.
Multi-threaded tests are often not reproducible due to the fact that there is no guarantee on the order in which operations occur across threads. Adding randomization to the mix usually makes things worse and should be done with care.
The code coverage report can be generated through Gradle with [JaCoCo plugin](https://docs.gradle.org/current/userguide/jacoco_plugin.html).
For unit test:
./gradlew codeCoverageReportForUnitTest
For integration test:
./gradlew codeCoverageReportForIntegrationTest
For the combined tests (unit and integration):
./gradlew codeCoverageReport
To generate coverage report for the combined tests after `check` task:
./gradlew check -Dtests.coverage=true
The code coverage report will be generated in `build/codeCoverageReport`, `build/codeCoverageReportForUnitTest` or `build/codeCoverageReportForIntegrationTest` correspondingly.
The report will be in XML format only by default, but you can add the following parameter for HTML and CSV format.
- To generate report in HTML format: `-Dtests.coverage.report.html=true`
- To generate report in CSV format: `-Dtests.coverage.report.csv=true`
- To NOT generate report in XML format: `-Dtests.coverage.report.xml=false`
For example, to generate code coverage report in HTML format and not in XML format:
Apart from using Gradle, it is also 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.
Additional plugins may be built alongside OpenSearch, where their dependency on OpenSearch will be substituted with the local OpenSearch build. To add your plugin, create a directory called `opensearch-extra` as a sibling of OpenSearch. Checkout your plugin underneath `opensearch-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.
There is a known issue with macOS localhost resolve strategy that can cause some integration tests to fail. This is because integration tests have timings for cluster formation, discovery, etc. that can be exceeded if name resolution takes a long time. To fix this, make sure you have your computer name (as returned by `hostname`) inside `/etc/hosts`, e.g.:
