Functional Tests for TempestaFW

Recommended configuration

Running tests during development process can cause crashes to TempestaFW. Since TempestaFW is implemented as a set of kernel modules it is not convenient to run testing framework on the same host. It is recommended to run TempestaFW on a separated host.

Recommended test-beds:

• Local testing. All parts of the testing framework are running on the same host. The simplest configuration to check that current revision of TempestaFW passes all the functional tests. It is default configuration.

    ┌──────────────────────────────────────────────────────┐
    │ Testing Framework + Client + TempestaFW + Web Server │
    └──────────────────────────────────────────────────────┘

• With isolated testing framework. 2 different hosts with their own roles are used. This configuration generates real network traffic. Handy for stress and performance testing but require a lot of resources. This configuration is recommended for TempestaFW developers.

    ┌───────────────────┐
    │    TempestaFW     ├────┐
    └──────┬────────────┘    │ Management over SSH
           │              ┌──┴──────────────────────────────────────┐
           │              │ Testing Framework + Client + Web Server │
           │              └───────────────┬─────────────────────────┘
           └──────────────────────────────┘
          Separated network for test traffic

Setup

To run requirements auto installation run setup.sh from tempesta-test directory as root:

./setup.sh

Requirements

• Python version till 3.11 is supported, version 3.12 is NOT supported (we use asyncore that was removed in 3.12)

• Host for testing framework: python3, wrk, ab, nghttp2, h2spec, curl, h2load, tls-perf, netstat, lxc, nginx, docker.io, web content directory accessible by nginx, nginx should not be running before the tests start. See Python libraries in requirements.txt

• All hosts except previous one: sftp-server

• Host for running TempestaFW: Linux kernel with Tempesta, TempestaFW sources, systemtap, tcpdump, bc

wrk is an HTTP benchmarking tool, available from Github.

ab is Apache benchmark tool, that can be found in apache2-utils package.

h2spec is HTTP/2 conformance test suite. Can't be installed from package manager and must be compiled from sources.

tls-perf can be downloaded from our GitHub repository.

Linux kernel for TempestaFW recommended to install using kernel_installer.py

Testing framework manages other hosts via SSH protocol, so the host running testing framework must be able to be authenticated on other hosts by the key. That can be done using ssh-copy-id. Root access is required on all hosts.

Requirements can be checked with check_deps/check_dependencies.sh. It should be ran from check_deps directory.

Run tests

Configuration

Testing framework is configured via tests_config.ini file. Example configuration is described in tests_config.ini.sample file. You can also create default tests configuration (see TestFrameworkCfg.defaults method from helpers/tf_cfg.py) by calling:

./run_tests.py -d

There is 4 sections in configuration: General, Client, Tempesta, Server.

Run tests

To run all the tests simply run:

./run_tests.py

To run individual tests, name them in the arguments to the run_tests.py script in dot-separated format (as if you were importing them as python modules, although it is also possible to run specific testcases or even methods inside a testcase):

./run_tests.py cache.test_cache
./run_tests.py cache.test_cache.TestCacheDisabled.test_cache_fullfill_all

Or you can run all tests from a file:

./run_tests.py selftests/test_deproxy.py 

Or you can run individual tests (or test class) using -H options:

./run_tests.py -H selftests/test_deproxy.py 
[?] Select test class: DeproxyTestH2
   DeproxyChunkedTest
   DeproxyClientTest
   DeproxyDummyTest
   DeproxyTest
   DeproxyTestFailOver
 > DeproxyTestH2
   ProtocolError

[?] Select test method: ALL
 > ALL
   test_bodyless
   test_bodyless_multiplexed
   test_disable_huffman_encoding
   test_get_4xx_response
   test_make_request
   test_no_parsing_make_request
   test_parsing_make_request
   test_with_body

To ignore specific tests, specify them in the arguments prefixed with - (you may need to use -- to avoid treating that as a flag):

./run_tests.py cache -cache.test_purge # run cache.*, except cache.test_purge.*
./run_tests.py -- -cache # run everything, except cache.*

If the testsuite was interrupted or aborted, next run will continue from the interruption point. The resumption information is stored in the tests_resume.txt file in the current working directory. It is also possible to resume the testsuite from a specific test:

./run_tests.py --resume flacky_net
./run_tests.py --resume-after cache.test_purge

In all cases, prefix specifications are allowed, i. e. cache.test_cache will match all tests in cache/test_cache.py, but test_cache will not match anything. When resuming, execution will continue from (after) the first test that matches the specified string.

Adding new tests

WARNING: there are 2 testing frameworks in directories testers and framework. Please use only framework.testet.TempestaTest for the new tests. testers.functional.FunctionalTest and testers.stress.StressTest are deprecated and must be removed in #56 .

Requirements to adding new tests:

1. Name of the test directory must be started with t_ prefix;
2. Name of the file must be started with test_ prefix;

mkdir t_new_directory
touch t_new_directory/test_some_feature.py
echo "__all__ = [ 'test_some_feature' ]" >> my_test/__init.py__

3. Name of the test class must be started with Test prefix;

from test_suite import tester

class TestCases(tester.TempestaTest):
    ...

4. Test class must contain TempestaFW, backend and client configuration. Each config is a structure, containing item id, type, and other options, depending on item type. TempestaFW config, deproxy response, addr and port can use templates in format ${part_variable} where part is one of 'server', 'tempesta', 'client' or 'backend'. For example:

backends = [
    {
        "id": "deproxy",
        "type": "deproxy",
        "port": "8000",
        "response": "static",
    },
    {
        "id": "nginx",
        "type": "nginx",
        "status_uri": "http://${server_ip}:8000/nginx_status",
        "config": "nginx config as string",
    }
]

clients = [
    {
        "id": "deproxy",
        "type": "deproxy_h2",  # "deproxy" for HTTP/1
        "addr": "${tempesta_ip}",
        "port": "443",
        "ssl": True,
    },
    {"id": "wrk", "type": "wrk", "addr": "${server_ip}:8000"},
    {
        "id": "external",
        "type": "external",
        "binary": "curl",
        "cmd_args": "-Ikf http://${tempesta_ip}:80/",
    },
    {"id": "curl", "type": "curl", "h2": True},
]

tempesta = {
    "config": """
        listen 80;
        server ${server_ip}:8000;
    """
}

5. We use decorators to parameterize the tests (please don't use inheritance):

from test_suite import tester
from test_suite import marks


@marks.parameterize_class(
  [
    {"name": "Http", "clients": ["http_config"]},
    {"name": "H2", "clients": ["h2_config"]},
  ]
)
class TestExample(tester.TempestaTest):
  @marks.Parameterize.expand(
    [
      marks.Param(name='1', key_1="value_1"),
      marks.Param(name='2', key_1="value_2"),
    ]
  )
  def test_request(self, name, key_1):
    ...

# we will get 4 tests:
# TestExampleHttp.test_request_1
# TestExampleHttp.test_request_2
# TestExampleH2.test_request_1
# TestExampleH2.test_request_2

Example tests can be found in selftests/test_framework.py

Tests can be skipped or marked as expected to fail. More info at Python documentation.

Testing with chunked messages

WARNING: only for deproxy client and server, and it only works on local configuration.

Some tests require division of request or response into small TCP segments ("chunks"). This division is controlled by segment_size parameter of the client or the backend (see above). Usualy better to set this parameter programmaticaly rather than in client or backend configuration. You can run any test with TCP segmentation using -T option:

./run_tests.py -T 10 selftests/test_deproxy.py 

Internal structure and motivation of user configured tests

User configured tests have very flexible structure. They allow arbitrary clients and server start, stop, making requests. This leads to several points in internal structure.

Using separate thread for polling cycle

Now, deproxy client and deproxy server, all of them use the single polling cycle. We have 3 cases of using deproxy clients and server:

1. both deproxy client and server are used

2. only deproxy client is used

3. only deproxy server is used

And case 3 leads to instant running of polling cycle in separate thread. Indeed, let's consider case of wrk client and deproxy server without instant running of this cycle. We start deproxy server, then we start wrk client and after this we start polling cycle. The time before starting cycle, wrk will get an errors. Ok, let's start polling cycle before wrk. But now it's impossible to start wrk, because we are in polling cycle. This problem appeares, because with running polling cycle in the same thread, as the main procedure, deproxy server can receive requests only after polling cycle starts.

The solution is to make possible handling requests exactly when server starts. In this case test procedure becames simple and straightforward: start deproxy server, the start wrk. And this became possible with polling cycle, running in separate thread.

But using separate thread leads to requirements of using locks. It's appeared that creating new connection while polling function is running in it's thread, can lead to error. So we should be sure, that it won't happen. That's why locks are used.

      Main thread                  Thread with poll loop

        |                                   |
        | ------------------------------- Lock()
        |                                   |
        |                                 Poll()
        |                                   |
        | ------------------------------ Unlock()
        |                                   |
        .                                   .
        .                                   .
        .                                   .
        |                                   |
        |                                 Lock()
client or server                            |
     start()                               Poll()
        \                                   |
         \                               Unlock()
        Lock() ---------------------------- |
          |                                 |
    create socket                           |
          |                                 |
    connect or listen                       |
          |                                 |
      Unlock() ---------------------------- |
          |                               Lock()
        return                              |
         /                                Poll()
        |                                   |
        |                                Unlock()
        |                                   |
        .                                   .
        .                                   .
        .                                   .

Classes used

Code of configurable tests located in framework/ directory. It contains basic class for configurable test and classes for items. Also it contains class for deproxy management and polling cycle.

TempestaTest

Basic class for user configured tests. Contains parsing of used items declaration (clients, backends, tempesta), startup and teardown functions. User configured tests should inherit it.

Also there are cases when you most likely would want to create a basic abstract class for a group of tests and utilize Python's inheritance mechanism. In order to do that, just pass an argument base upon class creation, e.g.:

class HttpTablesTestBase(tester.TempestaTest, base=True):
    ...

and tests won't be called for that particular class.

Default base value is False.

Note that if you override setUp method, please, don't forget to put

...
super().setUp()
...

in there, otherwise this feature won't work properly.

DeproxyManager

This class is a stateful wrap for the run_deproxy_server() function. This function contains a polling cycle. DeproxyManager creates new thread for this function, and stops it, when received stop(). DeproxyManager starts in test setUp() and stops in tearDown(). So, polling cycle run all the test time.

FreePortsChecker

When we start backend, it can appear, that specified port is already used by smth. So server startup will fail. We can make all servers to write about this, but it simpler to check free ports before start server.

Classes for servers and clients

deproxyclient, deproxyserver, nginx, wrk - this classes used for creating and handling corresponding types of items.

Development

In the project we use

Install dependencies: pip3 install -r requirements.txt

There may be a possible problem related to scapy, paramiko, and cryptography. paramiko will install cryptography==43.0.3, but scapy~=2.5.0rc2 cannot work with such a version of cryptography producing ModuleNotFoundError: No module named 'cryptography.hazmat.backends.openssl.ec' We added cryptography==38.0.2 on the top of requirements.txt to install it first.

If you still encounter a mentioned exception, try to run the next commands:

pip uninstall -y cryptography
pip install cryptography==38.0.2

Run pre-commit install to set up the git hook script.

Run pre-commit autoupdate for update to the latest repos' versions (optional).

Configuration files: wemake - tox.ini, black and isort - pyproject.toml, pre-commit - .pre-commit-config.yaml.

Run formatters isort <source_file_or_directory> and black <source_file_or_directory>

Run linter flake8 <target>:

where tagret is optional parameter, it defines target file to be checked, if omitted, checks is going to be processed on all files in running directory.

Use git commit -v --all to format all changed python files or just use git commit -m <msg>.

Resources

There are not so much good references about best practices in development of testing framework.

• Why Good Developers Write Bad Tests