* added a randomize flag and corresponding -r command line argument that

allows the caller to execute the various tests in pseudo-random order -
  default is still to execute tests in the order returned by findtests().

* moved initialization of the various flag variables to the main() function
  definition, making it possible to execute regrtest.main() interactively
  and still override default behavior.

Lib/test/regrtest.py

@@ -13,6 +13,7 @@ Command line options:
 -g: generate -- write the output file for a test instead of comparing it
 -x: exclude  -- arguments are tests to *exclude*
 -s: single   -- run only a single test (see below)
+-r: random   -- randomize test execution order
 
 If non-option arguments are present, they are names for tests to run,
 unless -x is given, in which case they are names for tests not to run.
@@ -33,10 +34,12 @@ import string
 import os
 import getopt
 import traceback
+import random
 
 import test_support
 
-def main(tests=None, testdir=None):
+def main(tests=None, testdir=None, verbose=0, quiet=0, generate=0,
+         exclude=0, single=0, randomize=0):
     """Execute a test suite.
 
     This also parses command-line options and modifies its behaviour
@@ -52,26 +55,26 @@ def main(tests=None, testdir=None):
     If the tests argument is omitted, the tests listed on the
     command-line will be used.  If that's empty, too, then all *.py
     files beginning with test_ will be used.
-    
+
+    The other six default arguments (verbose, quiet, generate, exclude,
+    single, and randomize) allow programmers calling main() directly to
+    set the values that would normally be set by flags on the command
+    line.
     """
     
     try:
-        opts, args = getopt.getopt(sys.argv[1:], 'vgqxs')
+        opts, args = getopt.getopt(sys.argv[1:], 'vgqxsr')
     except getopt.error, msg:
         print msg
         print __doc__
         return 2
-    verbose = 0
-    quiet = 0
-    generate = 0
-    exclude = 0
-    single = 0
     for o, a in opts:
         if o == '-v': verbose = verbose+1
         if o == '-q': quiet = 1; verbose = 0
         if o == '-g': generate = 1
         if o == '-x': exclude = 1
         if o == '-s': single = 1
+        if o == '-r': randomize = 1
     if generate and verbose:
         print "-g and -v don't go together!"
         return 2
@@ -104,6 +107,8 @@ def main(tests=None, testdir=None):
     tests = tests or args or findtests(testdir, stdtests, nottests)
     if single:
         tests = tests[:1]
+    if randomize:
+        random.shuffle(tests)
     test_support.verbose = verbose      # Tell tests to be moderately quiet
     save_modules = sys.modules.keys()
     for test in tests: