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