VictoriaMetrics/apptest/README.md
Artem Fetishev d7b3589dbd
tests: Initial version of integration tests (#7253)
### Describe Your Changes

Related issue: #7199 

This is the initial version of the integration tests for cluster. See
`README.md` for details.

Currently cluster only, but it can also be used for vm-single if needed.

The code has been added to the apptest package that resides in the root
directory of the VM codebase. This is done to exclude the integration
tests from regular testing build targets because:

- Most of the test variants do not apply to integration testing (such as
pure or race).
- The integtation tests may also be slow because each test must wait for
2 seconds so vmstorage flushes pending content). It may be okay when
there are a few tests but when there is a 100 of them running tests will
require much more time which will affect the developer wait time and CI
workflows.
- Finally, the integration tests may be flaky especially short term.

An alternative approach would be placing apptest under app package and
exclude apptest from packages under test, but that is not trivial.

The integration tests rely on retrieving some application runtime info
from the application logs, namely the application's host:port. Therefore
some changes to lib/httpserver/httpserver.go were necessary, such as
reporting the effective host:port instead the one from the flag.

### Checklist

The following checks are **mandatory**:

- [x] My change adheres [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/contributing/).

---------

Signed-off-by: Artem Fetishev <rtm@victoriametrics.com>
2024-10-30 15:22:06 +01:00

2 KiB

App Integration Tests

The apptest package contains the integration tests for the VictoriaMetrics applications (such as vmstorage, vminsert, and vmselect).

An integration test aims at verifying the behavior of an application as a whole, as apposed to a unit test that verifies the behavior of a building block of an application.

To achieve that an integration test starts an application in a separate process and then issues HTTP requets to it and verifies the responses, examines the metrics the app exposes and/or files it creates, etc.

Note that an object of testing may be not just a single app, but several apps working together. A good example is VictoriaMetrics cluster. An integration test may reproduce an arbitrary cluster configuration and verify how the components work together as a system.

The package provides a collection of helpers to start applications and make queries to them:

  • app.go - contains the generic code for staring an application and should not be used by integration tests directly.
  • {vmstorage,vminsert,etc}.go - build on top of app.go and provide the code for staring a specific application.
  • client.go - provides helper functions for sending HTTP requests to applications.

The integration tests themselves reside in *_test.go files. Apart from having the _test suffix, there are no strict rules of how to name a file, but the name should reflect the prevailing purpose of the tests located in that file. For example, sharding_test.go aims at testing data sharding.

Since integration tests start applications in a separate process, they require the application binary files to be built and put into the bin directory. The build rule used for running integration tests, make integration-test, accounts for that, it builds all application binaries before running the tests. But if you want to run the tests without make, i.e. by executing go test ./app/apptest, you will need to build the binaries first (for example, by executing make all).