7943c90b2e
Type: docs Signed-off-by: Maros Ondrejicka <maros.ondrejicka@pantheon.tech> Change-Id: I47d2794283a85a644448e60538f543644a0edfdc
241 lines
11 KiB
ReStructuredText
Executable File
241 lines
11 KiB
ReStructuredText
Executable File
Host stack test framework
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=========================
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Overview
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--------
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The goal of the Host stack test framework (**hs-test**) is to ease writing and running end-to-end tests for VPP's Host Stack.
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End-to-end tests often want multiple VPP instances, network namespaces, different types of interfaces
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and to execute external tools or commands. With such requirements the existing VPP test framework is not sufficient.
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For this, ``Go`` was chosen as a high level language, allowing rapid development, with ``Docker`` and ``ip`` being the tools for creating required topology.
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Go's package `testing`_ together with `go test`_ command form the base framework upon which the *hs-test* is built and run.
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Anatomy of a test case
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----------------------
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**Prerequisites**:
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* Tests use *hs-test*'s own docker image, so building it before starting tests is a prerequisite. Run ``sudo make`` to do so
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* Docker has to be installed and Go has to be in path of both the running user and root
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* Root privileges are required to run tests as it uses Linux ``ip`` command for configuring topology
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**Action flow when running a test case**:
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#. It starts with running ``./test``. This script is basically a wrapper for ``go test`` and accepts its parameters,
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for example following runs a specific test: ``./test -run TestNs/TestHttpTps``
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#. ``go test`` compiles package ``main`` along with any files with names matching the file pattern ``*_test.go``
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and then runs the resulting test binaries
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#. The go test framework runs each function matching :ref:`naming convention<test-convention>`. Each of these corresponds to a `test suite`_
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#. Testify toolkit's ``suite.Run(t *testing.T, suite TestingSuite)`` function runs the suite and does the following:
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#. Suite is initialized. The topology is loaded and configured in this step
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#. Test suite runs all the tests attached to it
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#. Execute tear-down functions, which currently consists of stopping running containers
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and clean-up of test topology
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Adding a test case
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------------------
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This describes adding a new test case to an existing suite.
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For adding a new suite, please see `Modifying the framework`_ below.
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#. To write a new test case, create a file whose name ends with ``_test.go`` or pick one that already exists
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#. Declare method whose name starts with ``Test`` and specifies its receiver as a pointer to the suite's struct (defined in ``framework_test.go``)
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#. Implement test behaviour inside the test method. This typically includes the following:
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#. Start docker container(s) as needed. Function ``dockerRun(instance, args string)``
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from ``utils.go`` serves this purpose. Alternatively use suite struct's ``NewContainer(name string)`` method
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#. Execute *hs-test* action(s) inside any of the running containers.
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Function ``hstExec`` from ``utils.go`` does this by using ``docker exec`` command to run ``hs-test`` executable.
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For starting an VPP instance inside a container, the ``Vpp`` struct can be used as a forward-looking alternative
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#. Run arbitrary commands inside the containers with ``dockerExec(cmd string, instance string)``
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#. Run other external tool with one of the preexisting functions in the ``utils.go`` file.
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For example, use ``wget`` with ``startWget(..)`` function
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#. Use ``exechelper`` or just plain ``exec`` packages to run whatever else
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#. ``defer func() { exechelper.Run("docker stop <container-name>) }()`` inside the method body,
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to stop the running container(s). It's not necessary to do this if containers were created
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with suite's ``NewContainer(..)`` method
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**Example test case**
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Two docker containers, each with its own VPP instance running. One VPP then pings the other.
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This can be put in file ``extras/hs-test/my_test.go`` and run with command ``./test -run TestMySuite``.
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::
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package main
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import (
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"fmt"
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"github.com/edwarnicke/exechelper"
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)
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func (s *MySuite) TestMyCase() {
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t := s.T()
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vpp1Instance := "vpp-1"
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vpp2Instance := "vpp-2"
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err := dockerRun(vpp1Instance, "")
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if err != nil {
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t.Errorf("%v", err)
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return
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}
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defer func() { exechelper.Run("docker stop " + vpp1Instance) }()
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err = dockerRun(vpp2Instance, "")
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if err != nil {
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t.Errorf("%v", err)
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return
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}
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defer func() { exechelper.Run("docker stop " + vpp2Instance) }()
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_, err = hstExec("Configure2Veths srv", vpp1Instance)
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if err != nil {
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t.Errorf("%v", err)
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return
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}
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_, err = hstExec("Configure2Veths cln", vpp2Instance)
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if err != nil {
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t.Errorf("%v", err)
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return
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}
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// ping one VPP from the other
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//
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// not using dockerExec because it executes in detached mode
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// and we want to capture output from ping and show it
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command := "docker exec --detach=false vpp-1 vppctl -s /tmp/2veths/var/run/vpp/cli.sock ping 10.10.10.2"
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output, err := exechelper.CombinedOutput(command)
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if err != nil {
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t.Errorf("ping failed: %v", err)
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}
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fmt.Println(string(output))
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}
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Modifying the framework
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-----------------------
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**Adding a test suite**
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.. _test-convention:
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#. Adding a new suite takes place in ``framework_test.go``
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#. Make a ``struct`` with at least ``HstSuite`` struct and a ``teardownSuite`` function as its members.
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HstSuite provides functionality that can be shared for all suites, like starting containers
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::
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type MySuite struct {
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HstSuite
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teardownSuite func()
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}
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#. Implement SetupSuite method which testify runs before running the tests.
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It's important here to call ``setupSuite(s *suite.Suite, topologyName string)`` and assign its result to the suite's ``teardownSuite`` member.
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Pass the topology name to the function in the form of file name of one of the *yaml* files in ``topo`` folder.
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Without the extension. In this example, *myTopology* corresponds to file ``extras/hs-test/topo/myTopology.yaml``
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::
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func (s *MySuite) SetupSuite() {
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// Add custom setup code here
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s.teardownSuite = setupSuite(&s.Suite, "myTopology")
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}
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#. Implement TearDownSuite method which testify runs after the tests, to clean-up.
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It's good idea to add at least the suite's own ``teardownSuite()``
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and HstSuite upper suite's ``stopContainers()`` methods
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::
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func (s *MySuite) TearDownSuite() {
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s.teardownSuite()
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s.StopContainers()
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}
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#. In order for ``go test`` to run this suite, we need to create a normal test function and pass our suite to ``suite.Run``
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::
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func TestMySuite(t *testing.T) {
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var m MySuite
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suite.Run(t, &m)
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}
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#. Next step is to add test cases to the suite. For that, see section `Adding a test case`_ above
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**Adding a topology element**
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Topology configuration exists as ``yaml`` files in the ``extras/hs-test/topo`` folder.
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Processing of a file for a particular test suite is started by the ``setupSuite`` function depending on which file's name is passed to it.
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Specified file is loaded by ``LoadTopology()`` function and converted into internal data structures which represent various elements of the topology.
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After parsing the configuration, ``Configure()`` method loops over array of topology elements and configures them one by one.
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These are currently supported types of elements.
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* ``netns`` - network namespace
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* ``veth`` - veth network interface, optionally with target network namespace or IPv4 address
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* ``bridge`` - ethernet bridge to connect created interfaces, optionally with target network namespace
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* ``tap`` - tap network interface with IP address
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Supporting a new type of topology element requires adding code to recognize the new element type during loading.
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And adding code to set up the element in the host system with some Linux tool, such as *ip*. This should be implemented in ``netconfig.go``.
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**Communicating between containers**
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When two VPP instances or other applications, each in its own Docker container,
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want to communicate there are typically two ways this can be done within *hs-test*.
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* Network interfaces. Containers are being created with ``-d --network host`` options,
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so they are connected with interfaces created in host system
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* Shared folders. Containers are being created with ``-v`` option to create shared `volumes`_ between host system and containers
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or just between containers
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**Adding a hs-test action**
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Executing more complex or long running jobs is made easier by *hs-test* actions.
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These are functions that compartmentalize configuration and execution together for a specific task.
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For example, starting up VPP or running VCL echo client.
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The actions are located in ``extras/hs-test/actions.go``. To add one, create a new method that has its receiver as a pointer to ``Actions`` struct.
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Run it from test case with ``hstExec(args, instance)`` where ``args`` is the action method's name and ``instance`` is target Docker container's name.
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This then executes the ``hs-test`` binary inside of the container and it then runs selected action.
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Action is specified by its name as first argument for the binary.
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*Note*: When ``hstExec(..)`` runs some action from a test case, the execution of ``hs-test`` inside the container
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is asynchronous. The action might take many seconds to finish, while the test case execution context continues to run.
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To mitigate this, ``hstExec(..)`` waits pre-defined arbitrary number of seconds for a *sync file* to be written by ``hs-test``
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at the end of its run. The test case context and container use Docker volume to share the file.
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**Adding an external tool**
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If an external program should be executed as part of a test case, it might be useful to wrap its execution in its own function.
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These types of functions are placed in the ``utils.go`` file. If the external program is not available by default in Docker image,
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add its installation to ``extras/hs-test/Dockerfile.vpp`` in ``apt-get install`` command.
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Alternatively copy the executable from host system to the Docker image, similarly how the VPP executables and libraries are being copied.
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**Eternal dependencies**
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* Linux tools ``ip``, ``brctl``
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* Standalone programs ``wget``, ``iperf3`` - since these are downloaded when Docker image is made,
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they are reasonably up-to-date automatically
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* Programs in Docker images - see ``envoyproxy/envoy-contrib`` in ``utils.go``
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* ``http_server`` - homegrown application that listens on specified address and sends a test file in response
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* Non-standard Go libraries - see ``extras/hs-test/go.mod``
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Generally, these will be updated on a per-need basis, for example when a bug is discovered
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or a new version incompatibility issue occurs.
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.. _testing: https://pkg.go.dev/testing
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.. _go test: https://pkg.go.dev/cmd/go#hdr-Test_packages
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.. _test suite: https://github.com/stretchr/testify#suite-package
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.. _volumes: https://docs.docker.com/storage/volumes/
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