README.md
1<!--
2Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
3
4SPDX-License-Identifier: curl
5-->
6
7# The curl HTTP Test Suite
8
9This is an additional test suite using a combination of Apache httpd and nghttpx servers to perform various tests beyond the capabilities of the standard curl test suite.
10
11# Usage
12
13The test cases and necessary files are in `tests/http`. You can invoke `pytest` from there or from the top level curl checkout and it will find all tests.
14
15```
16curl> pytest test/http
17platform darwin -- Python 3.9.15, pytest-6.2.0, py-1.10.0, pluggy-0.13.1
18rootdir: /Users/sei/projects/curl
19collected 5 items
20
21tests/http/test_01_basic.py .....
22```
23
24Pytest takes arguments. `-v` increases its verbosity and can be used several times. `-k <expr>` can be used to run only matching test cases. The `expr` can be something resembling a python test or just a string that needs to match test cases in their names.
25
26```
27curl/tests/http> pytest -vv -k test_01_02
28```
29
30runs all test cases that have `test_01_02` in their name. This does not have to be the start of the name.
31
32Depending on your setup, some test cases may be skipped and appear as `s` in the output. If you run pytest verbose, it will also give you the reason for skipping.
33
34# Prerequisites
35
36You will need:
37
381. a recent Python, the `cryptography` module and, of course, `pytest`
392. an apache httpd development version. On Debian/Ubuntu, the package `apache2-dev` has this.
403. a local `curl` project build
413. optionally, a `nghttpx` with HTTP/3 enabled or h3 test cases will be skipped.
42
43### Configuration
44
45Via curl's `configure` script you may specify:
46
47 * `--with-test-nghttpx=<path-of-nghttpx>` if you have nghttpx to use somewhere outside your `$PATH`.
48 * `--with-test-httpd=<httpd-install-path>` if you have an Apache httpd installed somewhere else. On Debian/Ubuntu it will otherwise look into `/usr/bin` and `/usr/sbin` to find those.
49 * `--with-test-caddy=<caddy-install-path>` if you have a Caddy web server installed somewhere else.
50 * `--with-test-vsftpd=<vsftpd-install-path>` if you have a vsftpd ftp server installed somewhere else.
51
52## Usage Tips
53
54Several test cases are parameterized, for example with the HTTP version to use. If you want to run a test with a particular protocol only, use a command line like:
55
56```
57curl/tests/http> pytest -k "test_02_06 and h2"
58```
59
60Test cases can be repeated, with the `pytest-repeat` module (`pip install pytest-repeat`). Like in:
61
62```
63curl/tests/http> pytest -k "test_02_06 and h2" --count=100
64```
65
66which then runs this test case a hundred times. In case of flaky tests, you can make pytest stop on the first one with:
67
68```
69curl/tests/http> pytest -k "test_02_06 and h2" --count=100 --maxfail=1
70```
71
72which allow you to inspect output and log files for the failed run. Speaking of log files, the verbosity of pytest is also used to collect curl trace output. If you specify `-v` three times, the `curl` command is started with `--trace`:
73
74```
75curl/tests/http> pytest -vvv -k "test_02_06 and h2" --count=100 --maxfail=1
76```
77
78all of curl's output and trace file are found in `tests/http/gen/curl`.
79
80## Writing Tests
81
82There is a lot of [`pytest` documentation](https://docs.pytest.org/) with examples. No use in repeating that here. Assuming you are somewhat familiar with it, it is useful how *this* general test suite is setup. Especially if you want to add test cases.
83
84### Servers
85
86In `conftest.py` 3 "fixtures" are defined that are used by all test cases:
87
881. `env`: the test environment. It is an instance of class `testenv/env.py:Env`. It holds all information about paths, availability of features (HTTP/3), port numbers to use, domains and SSL certificates for those.
892. `httpd`: the Apache httpd instance, configured and started, then stopped at the end of the test suite. It has sites configured for the domains from `env`. It also loads a local module `mod_curltest?` and makes it available in certain locations. (more on mod_curltest below).
903. `nghttpx`: an instance of nghttpx that provides HTTP/3 support. `nghttpx` proxies those requests to the `httpd` server. In a direct mapping, so you may access all the resources under the same path as with HTTP/2. Only the port number used for HTTP/3 requests will be different.
91
92`pytest` manages these fixture so that they are created once and terminated before exit. This means you can `Ctrl-C` a running pytest and the server will shutdown. Only when you brutally chop its head off, might there be servers left
93behind.
94
95### Test Cases
96
97Tests making use of these fixtures have them in their parameter list. This tells pytest that a particular test needs them, so it has to create them. Since one can invoke pytest for just a single test, it is important that a test references the ones it needs.
98
99All test cases start with `test_` in their name. We use a double number scheme to group them. This makes it ease to run only specific tests and also give a short mnemonic to communicate trouble with others in the project. Otherwise you are free to name test cases as you think fitting.
100
101Tests are grouped thematically in a file with a single Python test class. This is convenient if you need a special "fixture" for several tests. "fixtures" can have "class" scope.
102
103There is a curl helper class that knows how to invoke curl and interpret its output. Among other things, it does add the local CA to the command line, so that SSL connections to the test servers are verified. Nothing prevents anyone from running curl directly, for specific uses not covered by the `CurlClient` class.
104
105### mod_curltest
106
107The module source code is found in `testenv/mod_curltest`. It is compiled using the `apxs` command, commonly provided via the `apache2-dev` package. Compilation is quick and done once at the start of a test run.
108
109The module adds 2 "handlers" to the Apache server (right now). Handler are pieces of code that receive HTTP requests and generate the response. Those handlers are:
110
111* `curltest-echo`: hooked up on the path `/curltest/echo`. This one echoes a request and copies all data from the request body to the response body. Useful for simulating upload and checking that the data arrived as intended.
112* `curltest-tweak`: hooked up on the path `/curltest/tweak`. This handler is more of a Swiss army knife. It interprets parameters from the URL query string to drive its behavior.
113 * `status=nnn`: generate a response with HTTP status code `nnn`.
114 * `chunks=n`: generate `n` chunks of data in the response body, defaults to 3.
115 * `chunk_size=nnn`: each chunk should contain `nnn` bytes of data. Maximum is 16KB right now.
116 * `chunkd_delay=duration`: wait `duration` time between writing chunks
117 * `delay=duration`: wait `duration` time to send the response headers
118 * `body_error=(timeout|reset)`: produce an error after the first chunk in the response body
119 * `id=str`: add `str` in the response header `request-id`
120
121`duration` values are integers, optionally followed by a unit. Units are:
122
123 * `d`: days (probably not useful here)
124 * `h`: hours
125 * `mi`: minutes
126 * `s`: seconds (the default)
127 * `ms`: milliseconds
128
129As you can see, `mod_curltest`'s tweak handler allow to simulate many kinds of responses. An example of its use is `test_03_01` where responses are delayed using `chunk_delay`. This gives the response a defined duration and the test uses that to reload `httpd` in the middle of the first request. A graceful reload in httpd lets ongoing requests finish, but will close the connection afterwards and tear down the serving process. The following request need then to open a new connection. This is verified by the test case.
130
