1 tdc - Linux Traffic Control (tc) unit testing 1 tdc - Linux Traffic Control (tc) unit testing suite
2 2
3 Author: Lucas Bates - lucasb@mojatatu.com 3 Author: Lucas Bates - lucasb@mojatatu.com
4 4
5 tdc is a Python script to load tc unit tests f 5 tdc is a Python script to load tc unit tests from a separate JSON file and
6 execute them inside a network namespace dedica 6 execute them inside a network namespace dedicated to the task.
7 7
8 8
9 REQUIREMENTS 9 REQUIREMENTS
10 ------------ 10 ------------
11 11
12 * Minimum Python version of 3.8. !! 12 * Minimum Python version of 3.4. Earlier 3.X versions may work but are not
>> 13 guaranteed.
13 14
14 * The kernel must have network namespace supp !! 15 * The kernel must have network namespace support
15 16
16 * The kernel must have veth support available 17 * The kernel must have veth support available, as a veth pair is created
17 prior to running the tests when using nsPlu !! 18 prior to running the tests.
18 <<
19 * The kernel must have the appropriate infras <<
20 unit tests. See the config file in this dir <<
21 features. As new tests will be added, confi <<
22 19
23 * All tc-related features being tested must b 20 * All tc-related features being tested must be built in or available as
24 modules. To check what is required in curr 21 modules. To check what is required in current setup run:
25 ./tdc.py -c 22 ./tdc.py -c
26 23
27 Note: 24 Note:
28 In the current release, tdc run will abort 25 In the current release, tdc run will abort due to a failure in setup or
29 teardown commands - which includes not bein 26 teardown commands - which includes not being able to run a test simply
30 because the kernel did not support a specif 27 because the kernel did not support a specific feature. (This will be
31 handled in a future version - the current w 28 handled in a future version - the current workaround is to run the tests
32 on specific test categories that your kerne 29 on specific test categories that your kernel supports)
33 30
34 31
35 BEFORE YOU RUN 32 BEFORE YOU RUN
36 -------------- 33 --------------
37 34
38 The path to the tc executable that will be mos 35 The path to the tc executable that will be most commonly tested can be defined
39 in the tdc_config.py file. Find the 'TC' entry 36 in the tdc_config.py file. Find the 'TC' entry in the NAMES dictionary and
40 define the path. 37 define the path.
41 38
42 If you need to test a different tc executable 39 If you need to test a different tc executable on the fly, you can do so by
43 using the -p option when running tdc: 40 using the -p option when running tdc:
44 ./tdc.py -p /path/to/tc 41 ./tdc.py -p /path/to/tc
45 42
46 43
47 RUNNING TDC 44 RUNNING TDC
48 ----------- 45 -----------
49 46
50 To use tdc, root privileges are required. Thi 47 To use tdc, root privileges are required. This is because the
51 commands being tested must be run as root. Th 48 commands being tested must be run as root. The code that enforces
52 execution by root uid has been moved into a pl 49 execution by root uid has been moved into a plugin (see PLUGIN
53 ARCHITECTURE, below). 50 ARCHITECTURE, below).
54 51
55 Tests that use a network device should have ns !! 52 If nsPlugin is linked, all tests are executed inside a network
56 requirement for that test. nsPlugin executes a !! 53 namespace to prevent conflicts within the host.
57 network namespace and creates a veth pair whic <<
58 cases. To disable execution within the namespa <<
59 to tdc when starting a test run; the veth pair <<
60 by the plugin. <<
61 54
62 Running tdc without any arguments will run all 55 Running tdc without any arguments will run all tests. Refer to the section
63 on command line arguments for more information 56 on command line arguments for more information, or run:
64 ./tdc.py -h 57 ./tdc.py -h
65 58
66 tdc will list the test names as they are being 59 tdc will list the test names as they are being run, and print a summary in
67 TAP (Test Anything Protocol) format when they 60 TAP (Test Anything Protocol) format when they are done. If tests fail,
68 output captured from the failing test will be 61 output captured from the failing test will be printed immediately following
69 the failed test in the TAP output. 62 the failed test in the TAP output.
70 63
71 64
72 OVERVIEW OF TDC EXECUTION 65 OVERVIEW OF TDC EXECUTION
73 ------------------------- 66 -------------------------
74 67
75 One run of tests is considered a "test suite" 68 One run of tests is considered a "test suite" (this will be refined in the
76 future). A test suite has one or more test ca 69 future). A test suite has one or more test cases in it.
77 70
78 A test case has four stages: 71 A test case has four stages:
79 72
80 - setup 73 - setup
81 - execute 74 - execute
82 - verify 75 - verify
83 - teardown 76 - teardown
84 77
85 The setup and teardown stages can run zero or 78 The setup and teardown stages can run zero or more commands. The setup
86 stage does some setup if the test needs it. T 79 stage does some setup if the test needs it. The teardown stage undoes
87 the setup and returns the system to a "neutral 80 the setup and returns the system to a "neutral" state so any other test
88 can be run next. These two stages require any 81 can be run next. These two stages require any commands run to return
89 success, but do not otherwise verify the resul 82 success, but do not otherwise verify the results.
90 83
91 The execute and verify stages each run one com 84 The execute and verify stages each run one command. The execute stage
92 tests the return code against one or more acce 85 tests the return code against one or more acceptable values. The
93 verify stage checks the return code for succes 86 verify stage checks the return code for success, and also compares
94 the stdout with a regular expression. 87 the stdout with a regular expression.
95 88
96 Each of the commands in any stage will run in 89 Each of the commands in any stage will run in a shell instance.
97 90
98 Each test is an atomic unit. A test that for w <<
99 definitions is a bug. <<
100 <<
101 A test that runs inside a namespace (requires <<
102 with other tests. <<
103 <<
104 Tests that use netdevsim or don't run inside a <<
105 to each other. <<
106 <<
107 91
108 USER-DEFINED CONSTANTS 92 USER-DEFINED CONSTANTS
109 ---------------------- 93 ----------------------
110 94
111 The tdc_config.py file contains multiple value 95 The tdc_config.py file contains multiple values that can be altered to suit
112 your needs. Any value in the NAMES dictionary 96 your needs. Any value in the NAMES dictionary can be altered without affecting
113 the tests to be run. These values are used in 97 the tests to be run. These values are used in the tc commands that will be
114 executed as part of the test. More will be add 98 executed as part of the test. More will be added as test cases require.
115 99
116 Example: 100 Example:
117 $TC qdisc add dev $DEV1 ingress 101 $TC qdisc add dev $DEV1 ingress
118 102
119 The NAMES values are used to substitute into t 103 The NAMES values are used to substitute into the commands in the test cases.
120 104
121 105
122 COMMAND LINE ARGUMENTS 106 COMMAND LINE ARGUMENTS
123 ---------------------- 107 ----------------------
124 108
125 Run tdc.py -h to see the full list of availabl 109 Run tdc.py -h to see the full list of available arguments.
126 110
>> 111 usage: tdc.py [-h] [-p PATH] [-D DIR [DIR ...]] [-f FILE [FILE ...]]
>> 112 [-c [CATG [CATG ...]]] [-e ID [ID ...]] [-l] [-s] [-i] [-v]
>> 113 [-d DEVICE] [-n NS] [-V]
>> 114
>> 115 Linux TC unit tests
>> 116
>> 117 optional arguments:
>> 118 -h, --help show this help message and exit
>> 119 -p PATH, --path PATH The full path to the tc executable to use
>> 120 -v, --verbose Show the commands that are being run
>> 121 -d DEVICE, --device DEVICE
>> 122 Execute the test case in flower category
>> 123
>> 124 selection:
>> 125 select which test cases: files plus directories; filtered by categories
>> 126 plus testids
>> 127
>> 128 -D DIR [DIR ...], --directory DIR [DIR ...]
>> 129 Collect tests from the specified directory(ies)
>> 130 (default [tc-tests])
>> 131 -f FILE [FILE ...], --file FILE [FILE ...]
>> 132 Run tests from the specified file(s)
>> 133 -c [CATG [CATG ...]], --category [CATG [CATG ...]]
>> 134 Run tests only from the specified category/ies, or if
>> 135 no category/ies is/are specified, list known
>> 136 categories.
>> 137 -e ID [ID ...], --execute ID [ID ...]
>> 138 Execute the specified test cases with specified IDs
>> 139
>> 140 action:
>> 141 select action to perform on selected test cases
>> 142
>> 143 -l, --list List all test cases, or those only within the
>> 144 specified category
>> 145 -s, --show Display the selected test cases
>> 146 -i, --id Generate ID numbers for new test cases
>> 147
>> 148 netns:
>> 149 options for nsPlugin(run commands in net namespace)
>> 150
>> 151 -n NS, --namespace NS
>> 152 Run commands in namespace NS
>> 153
>> 154 valgrind:
>> 155 options for valgrindPlugin (run command under test under Valgrind)
>> 156
>> 157 -V, --valgrind Run commands under valgrind
>> 158
>> 159
127 PLUGIN ARCHITECTURE 160 PLUGIN ARCHITECTURE
128 ------------------- 161 -------------------
129 162
130 There is now a plugin architecture, and some o 163 There is now a plugin architecture, and some of the functionality that
131 was in the tdc.py script has been moved into t 164 was in the tdc.py script has been moved into the plugins.
132 165
133 The plugins are in the directory plugin-lib. 166 The plugins are in the directory plugin-lib. The are executed from
134 directory plugins. Put symbolic links from pl 167 directory plugins. Put symbolic links from plugins to plugin-lib,
135 and name them according to the order you want !! 168 and name them according to the order you want them to run.
136 necessary if a test case being run requires a <<
137 169
138 Example: 170 Example:
139 171
140 bjb@bee:~/work/tc-testing$ ls -l plugins 172 bjb@bee:~/work/tc-testing$ ls -l plugins
141 total 4 173 total 4
142 lrwxrwxrwx 1 bjb bjb 27 Oct 4 16:12 10-r 174 lrwxrwxrwx 1 bjb bjb 27 Oct 4 16:12 10-rootPlugin.py -> ../plugin-lib/rootPlugin.py
143 lrwxrwxrwx 1 bjb bjb 25 Oct 12 17:55 20-n 175 lrwxrwxrwx 1 bjb bjb 25 Oct 12 17:55 20-nsPlugin.py -> ../plugin-lib/nsPlugin.py
144 -rwxr-xr-x 1 bjb bjb 0 Sep 29 15:56 __in 176 -rwxr-xr-x 1 bjb bjb 0 Sep 29 15:56 __init__.py
145 177
146 The plugins are a subclass of TdcPlugin, defin 178 The plugins are a subclass of TdcPlugin, defined in TdcPlugin.py and
147 must be called "SubPlugin" so tdc can find the 179 must be called "SubPlugin" so tdc can find them. They are
148 distinguished from each other in the python pr 180 distinguished from each other in the python program by their module
149 name. 181 name.
150 182
151 This base class supplies "hooks" to run extra 183 This base class supplies "hooks" to run extra functions. These hooks are as follows:
152 184
153 pre- and post-suite 185 pre- and post-suite
154 pre- and post-case 186 pre- and post-case
155 pre- and post-execute stage 187 pre- and post-execute stage
156 adjust-command (runs in all stages and receive 188 adjust-command (runs in all stages and receives the stage name)
157 189
158 The pre-suite hook receives the number of test 190 The pre-suite hook receives the number of tests and an array of test ids.
159 This allows you to dump out the list of skippe 191 This allows you to dump out the list of skipped tests in the event of a
160 failure during setup or teardown stage. 192 failure during setup or teardown stage.
161 193
162 The pre-case hook receives the ordinal number 194 The pre-case hook receives the ordinal number and test id of the current test.
163 195
164 The adjust-command hook receives the stage id 196 The adjust-command hook receives the stage id (see list below) and the
165 full command to be executed. This allows for 197 full command to be executed. This allows for last-minute adjustment
166 of the command. 198 of the command.
167 199
168 The stages are identified by the following str 200 The stages are identified by the following strings:
169 201
170 - pre (pre-suite) 202 - pre (pre-suite)
171 - setup 203 - setup
172 - command 204 - command
173 - verify 205 - verify
174 - teardown 206 - teardown
175 - post (post-suite) 207 - post (post-suite)
176 208
177 209
178 To write a plugin, you need to inherit from Td 210 To write a plugin, you need to inherit from TdcPlugin in
179 TdcPlugin.py. To use the plugin, you have to 211 TdcPlugin.py. To use the plugin, you have to put the
180 implementation file in plugin-lib, and add a s 212 implementation file in plugin-lib, and add a symbolic link to it from
181 plugins. It will be detected at run time and 213 plugins. It will be detected at run time and invoked at the
182 appropriate times. There are a few examples i 214 appropriate times. There are a few examples in the plugin-lib
183 directory: 215 directory:
184 216
185 - rootPlugin.py: 217 - rootPlugin.py:
186 implements the enforcement of running as 218 implements the enforcement of running as root
187 - nsPlugin.py: 219 - nsPlugin.py:
188 sets up a network namespace and runs all !! 220 sets up a network namespace and runs all commands in that namespace
189 while also setting up dummy devices to b <<
190 - valgrindPlugin.py 221 - valgrindPlugin.py
191 runs each command in the execute stage u 222 runs each command in the execute stage under valgrind,
192 and checks for leaks. 223 and checks for leaks.
193 This plugin will output an extra test fo 224 This plugin will output an extra test for each test in the test file,
194 one is the existing output as to whether 225 one is the existing output as to whether the test passed or failed,
195 and the other is a test whether the comm 226 and the other is a test whether the command leaked memory or not.
196 (This one is a preliminary version, it m 227 (This one is a preliminary version, it may not work quite right yet,
197 but the overall template is there and it 228 but the overall template is there and it should only need tweaks.)
198 229
199 230
200 ACKNOWLEDGEMENTS 231 ACKNOWLEDGEMENTS
201 ---------------- 232 ----------------
202 233
203 Thanks to: 234 Thanks to:
204 235
205 Jamal Hadi Salim, for providing valuable test 236 Jamal Hadi Salim, for providing valuable test cases
206 Keara Leibovitz, who wrote the CLI test driver 237 Keara Leibovitz, who wrote the CLI test driver that I used as a base for the
207 first version of the tc testing suite. This 238 first version of the tc testing suite. This work was presented at
208 Netdev 1.2 Tokyo in October 2016. 239 Netdev 1.2 Tokyo in October 2016.
209 Samir Hussain, for providing help while I dove 240 Samir Hussain, for providing help while I dove into Python for the first time
210 and being a second eye for this code. 241 and being a second eye for this code.
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