Package CedarBackup2 :: Module testutil
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Source Code for Module CedarBackup2.testutil

  1  # -*- coding: iso-8859-1 -*- 
  2  # vim: set ft=python ts=3 sw=3 expandtab: 
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  4  # 
  5  #              C E D A R 
  6  #          S O L U T I O N S       "Software done right." 
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 10  # 
 11  # Copyright (c) 2004-2006,2008 Kenneth J. Pronovici. 
 12  # All rights reserved. 
 13  # 
 14  # This program is free software; you can redistribute it and/or 
 15  # modify it under the terms of the GNU General Public License, 
 16  # Version 2, as published by the Free Software Foundation. 
 17  # 
 18  # This program is distributed in the hope that it will be useful, 
 19  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 20  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 21  # 
 22  # Copies of the GNU General Public License are available from 
 23  # the Free Software Foundation website, http://www.gnu.org/. 
 24  # 
 25  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
 26  # 
 27  # Author   : Kenneth J. Pronovici <pronovic@ieee.org> 
 28  # Language : Python (>= 2.3) 
 29  # Project  : Cedar Backup, release 2 
 30  # Revision : $Id: testutil.py 879 2008-03-20 04:00:23Z pronovic $ 
 31  # Purpose  : Provides unit-testing utilities. 
 32  # 
 33  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
 34   
 35  ######################################################################## 
 36  # Module documentation 
 37  ######################################################################## 
 38   
 39  """ 
 40  Provides unit-testing utilities.  
 41   
 42  These utilities are kept here, separate from util.py, because they provide 
 43  common functionality that I do not want exported "publicly" once Cedar Backup 
 44  is installed on a system.  They are only used for unit testing, and are only 
 45  useful within the source tree. 
 46   
 47  Many of these functions are in here because they are "good enough" for unit 
 48  test work but are not robust enough to be real public functions.  Others (like 
 49  L{removedir}) do what they are supposed to, but I don't want responsibility for 
 50  making them available to others. 
 51   
 52  @sort: findResources, commandAvailable, 
 53         buildPath, removedir, extractTar, changeFileAge, 
 54         getMaskAsMode, getLogin, failUnlessAssignRaises, runningAsRoot, 
 55         platformMacOsX, platformWindows, platformHasEcho,  
 56         platformSupportsLinks, platformSupportsPermissions, 
 57         platformRequiresBinaryRead 
 58   
 59  @author: Kenneth J. Pronovici <pronovic@ieee.org> 
 60  """ 
 61   
 62   
 63  ######################################################################## 
 64  # Imported modules 
 65  ######################################################################## 
 66   
 67  import sys 
 68  import os 
 69  import tarfile 
 70  import time 
 71  import getpass 
 72  import random 
 73  import string 
 74  import platform 
 75  import logging 
 76  from StringIO import StringIO 
 77   
 78  from CedarBackup2.util import encodePath, executeCommand 
 79   
 80   
 81  ######################################################################## 
 82  # Public functions 
 83  ######################################################################## 
 84   
 85  ############################## 
 86  # setupDebugLogger() function 
 87  ############################## 
 88   
89 -def setupDebugLogger():
90 """ 91 Sets up a screen logger for debugging purposes. 92 93 Normally, the CLI functionality configures the logger so that 94 things get written to the right place. However, for debugging 95 it's sometimes nice to just get everything -- debug information 96 and output -- dumped to the screen. This function takes care 97 of that. 98 """ 99 logger = logging.getLogger("CedarBackup2") 100 logger.setLevel(logging.DEBUG) # let the logger see all messages 101 formatter = logging.Formatter(fmt="%(message)s") 102 handler = logging.StreamHandler(strm=sys.stdout) 103 handler.setFormatter(formatter) 104 handler.setLevel(logging.DEBUG) 105 logger.addHandler(handler)
106 107 108 ########################### 109 # findResources() function 110 ########################### 111
112 -def findResources(resources, dataDirs):
113 """ 114 Returns a dictionary of locations for various resources. 115 @param resources: List of required resources. 116 @param dataDirs: List of data directories to search within for resources. 117 @return: Dictionary mapping resource name to resource path. 118 @raise Exception: If some resource cannot be found. 119 """ 120 mapping = { } 121 for resource in resources: 122 for resourceDir in dataDirs: 123 path = os.path.join(resourceDir, resource); 124 if os.path.exists(path): 125 mapping[resource] = path 126 break 127 else: 128 raise Exception("Unable to find resource [%s]." % resource) 129 return mapping
130 131 132 ############################## 133 # commandAvailable() function 134 ############################## 135
136 -def commandAvailable(command):
137 """ 138 Indicates whether a command is available on $PATH somewhere. 139 This should work on both Windows and UNIX platforms. 140 @param command: Commang to search for 141 @return: Boolean true/false depending on whether command is available. 142 """ 143 if os.environ.has_key("PATH"): 144 for path in os.environ["PATH"].split(os.sep): 145 if os.path.exists(os.path.join(path, command)): 146 return True 147 return False
148 149 150 ####################### 151 # buildPath() function 152 ####################### 153
154 -def buildPath(components):
155 """ 156 Builds a complete path from a list of components. 157 For instance, constructs C{"/a/b/c"} from C{["/a", "b", "c",]}. 158 @param components: List of components. 159 @returns: String path constructed from components. 160 @raise ValueError: If a path cannot be encoded properly. 161 """ 162 path = components[0] 163 for component in components[1:]: 164 path = os.path.join(path, component) 165 return encodePath(path)
166 167 168 ####################### 169 # removedir() function 170 ####################### 171
172 -def removedir(tree):
173 """ 174 Recursively removes an entire directory. 175 This is basically taken from an example on python.com. 176 @param tree: Directory tree to remove. 177 @raise ValueError: If a path cannot be encoded properly. 178 """ 179 tree = encodePath(tree) 180 for root, dirs, files in os.walk(tree, topdown=False): 181 for name in files: 182 path = os.path.join(root, name) 183 if os.path.islink(path): 184 os.remove(path) 185 elif os.path.isfile(path): 186 os.remove(path) 187 for name in dirs: 188 path = os.path.join(root, name) 189 if os.path.islink(path): 190 os.remove(path) 191 elif os.path.isdir(path): 192 os.rmdir(path) 193 os.rmdir(tree)
194 195 196 ######################## 197 # extractTar() function 198 ######################## 199
200 -def extractTar(tmpdir, filepath):
201 """ 202 Extracts the indicated tar file to the indicated tmpdir. 203 @param tmpdir: Temp directory to extract to. 204 @param filepath: Path to tarfile to extract. 205 @raise ValueError: If a path cannot be encoded properly. 206 """ 207 tmpdir = encodePath(tmpdir) 208 filepath = encodePath(filepath) 209 tar = tarfile.open(filepath) 210 tar.posix = False 211 for tarinfo in tar: 212 tar.extract(tarinfo, tmpdir)
213 214 215 ########################### 216 # changeFileAge() function 217 ########################### 218
219 -def changeFileAge(filename, subtract=None):
220 """ 221 Changes a file age using the C{os.utime} function. 222 223 @note: Some platforms don't seem to be able to set an age precisely. As a 224 result, whereas we might have intended to set an age of 86400 seconds, we 225 actually get an age of 86399.375 seconds. When util.calculateFileAge() 226 looks at that the file, it calculates an age of 0.999992766204 days, which 227 then gets truncated down to zero whole days. The tests get very confused. 228 To work around this, I always subtract off one additional second as a fudge 229 factor. That way, the file age will be I{at least} as old as requested 230 later on. 231 232 @param filename: File to operate on. 233 @param subtract: Number of seconds to subtract from the current time. 234 @raise ValueError: If a path cannot be encoded properly. 235 """ 236 filename = encodePath(filename) 237 newTime = time.time() - 1; 238 if subtract is not None: 239 newTime -= subtract 240 os.utime(filename, (newTime, newTime))
241 242 243 ########################### 244 # getMaskAsMode() function 245 ########################### 246
247 -def getMaskAsMode():
248 """ 249 Returns the user's current umask inverted to a mode. 250 A mode is mostly a bitwise inversion of a mask, i.e. mask 002 is mode 775. 251 @return: Umask converted to a mode, as an integer. 252 """ 253 umask = os.umask(0777) 254 os.umask(umask) 255 return int(~umask & 0777) # invert, then use only lower bytes
256 257 258 ###################### 259 # getLogin() function 260 ###################### 261
262 -def getLogin():
263 """ 264 Returns the name of the currently-logged in user. This might fail under 265 some circumstances - but if it does, our tests would fail anyway. 266 """ 267 return getpass.getuser()
268 269 270 ############################ 271 # randomFilename() function 272 ############################ 273
274 -def randomFilename(length, prefix=None, suffix=None):
275 """ 276 Generates a random filename with the given length. 277 @param length: Length of filename. 278 @return Random filename. 279 """ 280 characters = [None] * length 281 for i in xrange(length): 282 characters[i] = random.choice(string.uppercase) 283 if prefix is None: 284 prefix = "" 285 if suffix is None: 286 suffix = "" 287 return "%s%s%s" % (prefix, "".join(characters), suffix)
288 289 290 #################################### 291 # failUnlessAssignRaises() function 292 #################################### 293
294 -def failUnlessAssignRaises(testCase, exception, object, property, value):
295 """ 296 Equivalent of C{failUnlessRaises}, but used for property assignments instead. 297 298 It's nice to be able to use C{failUnlessRaises} to check that a method call 299 raises the exception that you expect. Unfortunately, this method can't be 300 used to check Python propery assignments, even though these property 301 assignments are actually implemented underneath as methods. 302 303 This function (which can be easily called by unit test classes) provides an 304 easy way to wrap the assignment checks. It's not pretty, or as intuitive as 305 the original check it's modeled on, but it does work. 306 307 Let's assume you make this method call:: 308 309 testCase.failUnlessAssignRaises(ValueError, collectDir, "absolutePath", absolutePath) 310 311 If you do this, a test case failure will be raised unless the assignment:: 312 313 collectDir.absolutePath = absolutePath 314 315 fails with a C{ValueError} exception. The failure message differentiates 316 between the case where no exception was raised and the case where the wrong 317 exception was raised. 318 319 @note: Internally, the C{missed} and C{instead} variables are used rather 320 than directly calling C{testCase.fail} upon noticing a problem because the 321 act of "failure" itself generates an exception that would be caught by the 322 general C{except} clause. 323 324 @param testCase: PyUnit test case object (i.e. self). 325 @param exception: Exception that is expected to be raised. 326 @param object: Object whose property is to be assigned to. 327 @param property: Name of the property, as a string. 328 @param value: Value that is to be assigned to the property. 329 330 @see: C{unittest.TestCase.failUnlessRaises} 331 """ 332 missed = False 333 instead = None 334 try: 335 exec "object.%s = value" % property 336 missed = True 337 except exception: pass 338 except Exception, e: instead = e 339 if missed: 340 testCase.fail("Expected assignment to raise %s, but got no exception." % (exception.__name__)) 341 if instead is not None: 342 testCase.fail("Expected assignment to raise %s, but got %s instead." % (ValueError, instead.__class__.__name__))
343 344 345 ########################### 346 # captureOutput() function 347 ########################### 348
349 -def captureOutput(callable):
350 """ 351 Captures the output (stdout, stderr) of a function or a method. 352 353 Some of our functions don't do anything other than just print output. We 354 need a way to test these functions (at least nominally) but we don't want 355 any of the output spoiling the test suite output. 356 357 This function just creates a dummy file descriptor that can be used as a 358 target by the callable function, rather than C{stdout} or C{stderr}. 359 360 @note: This method assumes that C{callable} doesn't take any arguments 361 besides keyword argument C{fd} to specify the file descriptor. 362 363 @param callable: Callable function or method. 364 365 @return: Output of function, as one big string. 366 """ 367 fd = StringIO() 368 callable(fd=fd) 369 result = fd.getvalue() 370 fd.close() 371 return result
372 373 374 ######################### 375 # _isPlatform() function 376 ######################### 377
378 -def _isPlatform(name):
379 """ 380 Returns boolean indicating whether we're running on the indicated platform. 381 @param name: Platform name to check, currently one of "windows" or "macosx" 382 """ 383 if name == "windows": 384 return platform.platform(True, True).startswith("Windows") 385 elif name == "macosx": 386 return sys.platform == "darwin" 387 else: 388 raise ValueError("Unknown platform [%s]." % name)
389 390 391 ############################ 392 # platformMacOsX() function 393 ############################ 394
395 -def platformMacOsX():
396 """ 397 Returns boolean indicating whether this is the Mac OS X platform. 398 """ 399 return _isPlatform("macosx")
400 401 402 ############################# 403 # platformWindows() function 404 ############################# 405
406 -def platformWindows():
407 """ 408 Returns boolean indicating whether this is the Windows platform. 409 """ 410 return _isPlatform("windows")
411 412 413 ################################### 414 # platformSupportsLinks() function 415 ################################### 416 424 425 426 ######################################### 427 # platformSupportsPermissions() function 428 ######################################### 429
430 -def platformSupportsPermissions():
431 """ 432 Returns boolean indicating whether the platform supports UNIX-style file permissions. 433 Some platforms, like Windows, do not support permissions, and tests need to take 434 this into account. 435 """ 436 return not platformWindows()
437 438 439 ######################################## 440 # platformRequiresBinaryRead() function 441 ######################################## 442
443 -def platformRequiresBinaryRead():
444 """ 445 Returns boolean indicating whether the platform requires binary reads. 446 Some platforms, like Windows, require a special flag to read binary data 447 from files. 448 """ 449 return platformWindows()
450 451 452 ############################# 453 # platformHasEcho() function 454 ############################# 455
456 -def platformHasEcho():
457 """ 458 Returns boolean indicating whether the platform has a sensible echo command. 459 On some platforms, like Windows, echo doesn't really work for tests. 460 """ 461 return not platformWindows()
462 463 464 ########################### 465 # runningAsRoot() function 466 ########################### 467
468 -def runningAsRoot():
469 """ 470 Returns boolean indicating whether the effective user id is root. 471 This is always true on platforms that have no concept of root, like Windows. 472 """ 473 if platformWindows(): 474 return True 475 else: 476 return os.geteuid() == 0
477 478 479 ############################## 480 # availableLocales() function 481 ############################## 482
483 -def availableLocales():
484 """ 485 Returns a list of available locales on the system 486 @return: List of string locale names 487 """ 488 locales = [] 489 output = executeCommand(["locale"], [ "-a", ], returnOutput=True, ignoreStderr=True)[1] 490 for line in output: 491 locales.append(line.rstrip()) 492 return locales
493 494 495 #################################### 496 # hexFloatLiteralAllowed() function 497 #################################### 498
499 -def hexFloatLiteralAllowed():
500 """ 501 Indicates whether hex float literals are allowed by the interpreter. 502 503 As far back as 2004, some Python documentation indicated that octal and hex 504 notation applies only to integer literals. However, prior to Python 2.5, it 505 was legal to construct a float with an argument like 0xAC. This check 506 provides a version-based indication of whether the current interpreter 507 supports that behavior. 508 509 This check exists so that unit tests can continue to test the same thing as 510 always for pre-2.5 interpreters (i.e. making sure backwards compatibility 511 doesn't break) while still continuing to work for later interpreters. 512 513 The returned value is True for Python <= 2.5, and False otherwise. 514 """ 515 if map(int, [sys.version_info[0], sys.version_info[1]]) < [2, 5]: 516 return True 517 return False
518