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| 1 | .Dd December 20, 2004 | ||
| 2 | .Os | ||
| 3 | .Dt TAP 3 | ||
| 4 | .Sh NAME | ||
| 5 | .Nm tap | ||
| 6 | .Nd write tests that implement the Test Anything Protocol | ||
| 7 | .Sh SYNOPSIS | ||
| 8 | .In tap.h | ||
| 9 | .Sh DESCRIPTION | ||
| 10 | The | ||
| 11 | .Nm | ||
| 12 | library provides functions for writing test scripts that produce output | ||
| 13 | consistent with the Test Anything Protocol. A test harness that parses | ||
| 14 | this protocol can run these tests and produce useful reports indicating | ||
| 15 | their success or failure. | ||
| 16 | .Ss PRINTF STRINGS | ||
| 17 | In the descriptions that follow, for any function that takes as the | ||
| 18 | last two parameters | ||
| 19 | .Dq Fa char * , Fa ... | ||
| 20 | it can be assumed that the | ||
| 21 | .Fa char * | ||
| 22 | is a | ||
| 23 | .Fn printf | ||
| 24 | -like format string, and the optional arguments are values to be placed | ||
| 25 | in that string. | ||
| 26 | .Ss TEST PLANS | ||
| 27 | .Bl -tag -width indent | ||
| 28 | .It Xo | ||
| 29 | .Ft int | ||
| 30 | .Fn plan_tests "unsigned int" | ||
| 31 | .Xc | ||
| 32 | .It Xo | ||
| 33 | .Ft int | ||
| 34 | .Fn plan_no_plan "void" | ||
| 35 | .Xc | ||
| 36 | .It Xo | ||
| 37 | .Ft int | ||
| 38 | .Fn plan_skip_all "char *" "..." | ||
| 39 | .Xc | ||
| 40 | .El | ||
| 41 | .Pp | ||
| 42 | You must first specify a test plan. This indicates how many tests you | ||
| 43 | intend to run, and allows the test harness to notice if any tests were | ||
| 44 | missed, or if the test program exited prematurely. | ||
| 45 | .Pp | ||
| 46 | To do this, use | ||
| 47 | .Fn plan_tests , | ||
| 48 | which always returns 0. The function will cause your program to exit | ||
| 49 | prematurely if you specify 0 tests. | ||
| 50 | .Pp | ||
| 51 | In some situations you may not know how many tests you will be running, or | ||
| 52 | you are developing your test program, and do not want to update the | ||
| 53 | .Fn plan_tests | ||
| 54 | parameter every time you make a change. For those situations use | ||
| 55 | .Fn plan_no_plan . | ||
| 56 | It returns 0, and indicates to the test harness that an indeterminate number | ||
| 57 | of tests will be run. | ||
| 58 | .Pp | ||
| 59 | Both | ||
| 60 | .Fn plan_tests | ||
| 61 | and | ||
| 62 | .Fn plan_no_plan | ||
| 63 | will cause your test program to exit prematurely with a diagnostic | ||
| 64 | message if they are called more than once. | ||
| 65 | .Pp | ||
| 66 | If your test program detects at run time that some required functionality | ||
| 67 | is missing (for example, it relies on a database connection which is not | ||
| 68 | present, or a particular configuration option that has not been included | ||
| 69 | in the running kernel) use | ||
| 70 | .Fn plan_skip_all , | ||
| 71 | passing as parameters a string to display indicating the reason for skipping | ||
| 72 | the tests. | ||
| 73 | .Ss SIMPLE TESTS | ||
| 74 | .Bl -tag -width indent | ||
| 75 | .It Xo | ||
| 76 | .Ft unsigned int | ||
| 77 | .Fn ok "expression" "char *" "..." | ||
| 78 | .Xc | ||
| 79 | .It Xo | ||
| 80 | .Ft unsigned int | ||
| 81 | .Fn ok1 "expression" | ||
| 82 | .Xc | ||
| 83 | .It Xo | ||
| 84 | .Ft unsigned int | ||
| 85 | .Fn pass "char *" "..." | ||
| 86 | .Xc | ||
| 87 | .It Xo | ||
| 88 | .Ft unsigned int | ||
| 89 | .Fn fail "char *" "..." | ||
| 90 | .Xc | ||
| 91 | .El | ||
| 92 | .Pp | ||
| 93 | Tests are implemented as expressions checked by calls to the | ||
| 94 | .Fn ok | ||
| 95 | and | ||
| 96 | .Fn ok1 | ||
| 97 | macros. In both cases | ||
| 98 | .Fa expression | ||
| 99 | should evaluate to true if the test succeeded. | ||
| 100 | .Pp | ||
| 101 | .Fn ok | ||
| 102 | allows you to specify a name, or comment, describing the test which will | ||
| 103 | be included in the output. | ||
| 104 | .Fn ok1 | ||
| 105 | is for those times when the expression to be tested is self | ||
| 106 | explanatory and does not need an associated comment. In those cases | ||
| 107 | the test expression becomes the comment. | ||
| 108 | .Pp | ||
| 109 | These four calls are equivalent: | ||
| 110 | .Bd -literal -offset indent | ||
| 111 | int i = 5; | ||
| 112 | |||
| 113 | ok(i == 5, "i equals 5"); /* Overly verbose */ | ||
| 114 | ok(i == 5, "i equals %d", i); /* Just to demonstrate printf-like | ||
| 115 | behaviour of the test name */ | ||
| 116 | ok(i == 5, "i == 5"); /* Needless repetition */ | ||
| 117 | ok1(i == 5); /* Just right */ | ||
| 118 | .Ed | ||
| 119 | .Pp | ||
| 120 | It is good practice to ensure that the test name describes the meaning | ||
| 121 | behind the test rather than what you are testing. Viz | ||
| 122 | .Bd -literal -offset indent | ||
| 123 | ok(db != NULL, "db is not NULL"); /* Not bad, but */ | ||
| 124 | ok(db != NULL, "Database conn. succeeded"); /* this is better */ | ||
| 125 | .Ed | ||
| 126 | .Pp | ||
| 127 | .Fn ok | ||
| 128 | and | ||
| 129 | .Fn ok1 | ||
| 130 | return 1 if the expression evaluated to true, and 0 if it evaluated to | ||
| 131 | false. This lets you chain calls from | ||
| 132 | .Fn ok | ||
| 133 | to | ||
| 134 | .Fn diag | ||
| 135 | to only produce diagnostic output if the test failed. For example, this | ||
| 136 | code will include diagnostic information about why the database connection | ||
| 137 | failed, but only if the test failed. | ||
| 138 | .Bd -literal -offset indent | ||
| 139 | ok(db != NULL, "Database conn. succeeded") || | ||
| 140 | diag("Database error code: %d", dberrno); | ||
| 141 | .Ed | ||
| 142 | .Pp | ||
| 143 | You also have | ||
| 144 | .Fn pass | ||
| 145 | and | ||
| 146 | .Fn fail . | ||
| 147 | From the Test::More documentation: | ||
| 148 | .Bd -literal -offset indent | ||
| 149 | Sometimes you just want to say that the tests have passed. | ||
| 150 | Usually the case is you've got some complicated condition | ||
| 151 | that is difficult to wedge into an ok(). In this case, | ||
| 152 | you can simply use pass() (to declare the test ok) or fail | ||
| 153 | (for not ok). | ||
| 154 | |||
| 155 | Use these very, very, very sparingly. | ||
| 156 | .Ed | ||
| 157 | .Pp | ||
| 158 | These are synonyms for ok(1, ...) and ok(0, ...). | ||
| 159 | .Ss SKIPPING TESTS | ||
| 160 | .Bl -tag -width indent | ||
| 161 | .It Xo | ||
| 162 | .Ft int | ||
| 163 | .Fn skip "unsigned int" "char *" "..." | ||
| 164 | .Xc | ||
| 165 | .It Xo | ||
| 166 | .Fn skip_start "expression" "unsigned int" "char *" "..." | ||
| 167 | .Xc | ||
| 168 | .It Xo | ||
| 169 | .Sy skip_end | ||
| 170 | .Xc | ||
| 171 | .El | ||
| 172 | .Pp | ||
| 173 | Sets of tests can be skipped. Ordinarily you would do this because | ||
| 174 | the test can't be run in this particular testing environment. | ||
| 175 | .Pp | ||
| 176 | For example, suppose some tests should be run as root. If the test is | ||
| 177 | not being run as root then the tests should be skipped. In this | ||
| 178 | implementation, skipped tests are flagged as being ok, with a special | ||
| 179 | message indicating that they were skipped. It is your responsibility | ||
| 180 | to ensure that the number of tests skipped (the first parameter to | ||
| 181 | .Fn skip ) | ||
| 182 | is correct for the number of tests to skip. | ||
| 183 | .Pp | ||
| 184 | One way of implementing this is with a | ||
| 185 | .Dq do { } while(0); | ||
| 186 | loop, or an | ||
| 187 | .Dq if( ) { } else { } | ||
| 188 | construct, to ensure that there are no additional side effects from the | ||
| 189 | skipped tests. | ||
| 190 | .Bd -literal -offset indent | ||
| 191 | if(getuid() != 0) { | ||
| 192 | skip(1, "because test only works as root"); | ||
| 193 | } else { | ||
| 194 | ok(do_something_as_root() == 0, "Did something as root"); | ||
| 195 | } | ||
| 196 | .Ed | ||
| 197 | .Pp | ||
| 198 | Two macros are provided to assist with this. The previous example could | ||
| 199 | be re-written as follows. | ||
| 200 | .Bd -literal -offset indent | ||
| 201 | skip_start(getuid() != 0, 1, "because test only works as root"); | ||
| 202 | |||
| 203 | ok(do_something_as_root() == 0, "Did something as root"); | ||
| 204 | |||
| 205 | skip_end; /* It's a macro, no parentheses */ | ||
| 206 | .Ed | ||
| 207 | .Ss MARKING TESTS AS Dq TODO | ||
| 208 | .Bl -tag -width indent | ||
| 209 | .It Xo | ||
| 210 | .Ft void | ||
| 211 | .Fn todo_start "char *" "..." | ||
| 212 | .Xc | ||
| 213 | .It Xo | ||
| 214 | .Ft void | ||
| 215 | .Fn todo_end "void" | ||
| 216 | .Xc | ||
| 217 | .El | ||
| 218 | .Pp | ||
| 219 | Sets of tests can be flagged as being | ||
| 220 | .Dq TODO . | ||
| 221 | These are tests that you expect to fail, probably because you haven't | ||
| 222 | fixed a bug, or finished a new feature yet. These tests will still be | ||
| 223 | run, but with additional output that indicates that they are expected | ||
| 224 | to fail. Should a test start to succeed unexpectedly, tools like | ||
| 225 | .Xr prove 1 | ||
| 226 | will indicate this, and you can move the test out of the todo | ||
| 227 | block. This is much more useful than simply commenting out (or | ||
| 228 | .Dq #ifdef 0 ... #endif ) | ||
| 229 | the tests. | ||
| 230 | .Bd -literal -offset indent | ||
| 231 | todo_start("dwim() not returning true yet"); | ||
| 232 | |||
| 233 | ok(dwim(), "Did what the user wanted"); | ||
| 234 | |||
| 235 | todo_end(); | ||
| 236 | .Ed | ||
| 237 | .Pp | ||
| 238 | Should | ||
| 239 | .Fn dwim | ||
| 240 | ever start succeeding you will know about it as soon as you run the | ||
| 241 | tests. Note that | ||
| 242 | .Em unlike | ||
| 243 | the | ||
| 244 | .Fn skip_* | ||
| 245 | family, additional code between | ||
| 246 | .Fn todo_start | ||
| 247 | and | ||
| 248 | .Fn todo_end | ||
| 249 | .Em is | ||
| 250 | executed. | ||
| 251 | .Ss SKIP vs. TODO | ||
| 252 | From the Test::More documentation; | ||
| 253 | .Bd -literal -offset indent | ||
| 254 | If it's something the user might not be able to do, use SKIP. | ||
| 255 | This includes optional modules that aren't installed, running | ||
| 256 | under an OS that doesn't have some feature (like fork() or | ||
| 257 | symlinks), or maybe you need an Internet connection and one | ||
| 258 | isn't available. | ||
| 259 | |||
| 260 | If it's something the programmer hasn't done yet, use TODO. | ||
| 261 | This is for any code you haven't written yet, or bugs you have | ||
| 262 | yet to fix, but want to put tests in your testing script | ||
| 263 | (always a good idea). | ||
| 264 | .Ed | ||
| 265 | .Ss DIAGNOSTIC OUTPUT | ||
| 266 | .Bl -tag -width indent | ||
| 267 | .It Xo | ||
| 268 | .Fr unsigned int | ||
| 269 | .Fn diag "char *" "..." | ||
| 270 | .Xc | ||
| 271 | .El | ||
| 272 | .Pp | ||
| 273 | If your tests need to produce diagnostic output, use | ||
| 274 | .Fn diag . | ||
| 275 | It ensures that the output will not be considered by the TAP test harness. | ||
| 276 | .Fn diag | ||
| 277 | adds the necessary trailing | ||
| 278 | .Dq \en | ||
| 279 | for you. | ||
| 280 | .Bd -literal -offset indent | ||
| 281 | diag("Expected return code 0, got return code %d", rcode); | ||
| 282 | .Ed | ||
| 283 | .Pp | ||
| 284 | .Fn diag | ||
| 285 | always returns 0. | ||
| 286 | .Ss EXIT STATUS | ||
| 287 | .Bl -tag -width indent | ||
| 288 | .It Xo | ||
| 289 | .Fr int | ||
| 290 | .Fn exit_status void | ||
| 291 | .Xc | ||
| 292 | .El | ||
| 293 | .Pp | ||
| 294 | For maximum compatability your test program should return a particular | ||
| 295 | exit code. This is calculated by | ||
| 296 | .Fn exit_status | ||
| 297 | so it is sufficient to always return from | ||
| 298 | .Fn main | ||
| 299 | with either | ||
| 300 | .Dq return exit_status(); | ||
| 301 | or | ||
| 302 | .Dq exit(exit_status()); | ||
| 303 | as appropriate. | ||
| 304 | .Sh EXAMPLES | ||
| 305 | The | ||
| 306 | .Pa tests | ||
| 307 | directory in the source distribution contains numerous tests of | ||
| 308 | .Nm | ||
| 309 | functionality, written using | ||
| 310 | .Nm . | ||
| 311 | Examine them for examples of how to construct test suites. | ||
| 312 | .Sh COMPATABILITY | ||
| 313 | .Nm | ||
| 314 | strives to be compatible with the Perl Test::More and Test::Harness | ||
| 315 | modules. The test suite verifies that | ||
| 316 | .Nm | ||
| 317 | is bug-for-bug compatible with their behaviour. This is why some | ||
| 318 | functions which would more naturally return nothing return constant | ||
| 319 | values. | ||
| 320 | .Pp | ||
| 321 | If the | ||
| 322 | .Lb libpthread | ||
| 323 | is found at compile time, | ||
| 324 | .Nm | ||
| 325 | .Em should | ||
| 326 | be thread safe. Indications to the contrary (and test cases that expose | ||
| 327 | incorrect behaviour) are very welcome. | ||
| 328 | .Sh SEE ALSO | ||
| 329 | .Xr Test::More 1 , | ||
| 330 | .Xr Test::Harness 1 , | ||
| 331 | .Xr prove 1 | ||
| 332 | .Sh STANDARDS | ||
| 333 | .Nm | ||
| 334 | requires a | ||
| 335 | .St -isoC-99 | ||
| 336 | compiler. Some of the | ||
| 337 | .Nm | ||
| 338 | functionality is implemented as variadic macros, and that functionality | ||
| 339 | was not formally codified until C99. Patches to use | ||
| 340 | .Nm | ||
| 341 | with earlier compilers that have their own implementation of variadic | ||
| 342 | macros will be gratefully received. | ||
| 343 | .Sh HISTORY | ||
| 344 | .Nm | ||
| 345 | was written to help improve the quality and coverage of the FreeBSD | ||
| 346 | regression test suite, and released in the hope that others find it | ||
| 347 | a useful tool to help improve the quality of their code. | ||
| 348 | .Sh AUTHORS | ||
| 349 | .An "Nik Clayton" Aq nik@ngo.org.uk , | ||
| 350 | .Aq nik@FreeBSD.org | ||
| 351 | .Pp | ||
| 352 | .Nm | ||
| 353 | would not exist without the efforts of | ||
| 354 | .An "Michael G Schwern" Aq schqern@pobox.com , | ||
| 355 | .An "Andy Lester" Aq andy@petdance.com , | ||
| 356 | and the countless others who have worked on the Perl QA programme. | ||
| 357 | .Sh BUGS | ||
| 358 | Ideally, running the tests would have no side effects on the behaviour | ||
| 359 | of the application you are testing. However, it is not always possible | ||
| 360 | to avoid them. The following side effects of using | ||
| 361 | .Nm | ||
| 362 | are known. | ||
| 363 | .Bl -bullet -offset indent | ||
| 364 | .It | ||
| 365 | stdout is set to unbuffered mode after calling any of the | ||
| 366 | .Fn plan_* | ||
| 367 | functions. | ||
| 368 | .El | ||
