Index: lnt/tests/test_suite.py
===================================================================
--- lnt/tests/test_suite.py
+++ lnt/tests/test_suite.py
@@ -1,4 +1,4 @@
-import subprocess, tempfile, json, os, shlex, platform, pipes
+import subprocess, tempfile, json, os, shlex, platform, pipes, sys
 
 from optparse import OptionParser, OptionGroup
 
@@ -151,6 +151,20 @@
                          help="Do not submit the stat of this type [%default]",
                          action='append', choices=KNOWN_SAMPLE_KEYS,
                          type='choice', default=[])
+        group.add_option("", "--single-result", dest="single_result",
+                         help=("only execute one test and apply "
+                               "--single-result-predicate to calculate the "
+                               "exit status. Do not submit to a LNT instance "
+                               "or create a JSON report (useful for bisection)"))
+        group.add_option("", "--single-result-predicate",
+                         dest="single_result_predicate",
+                         help=("the predicate to apply to calculate the exit "
+                               "status (with --single-result). This is a Python "
+                               "expression that will be eval()ed with all metrics "
+                               "available as variables and a boolean 'status'. "
+                               "Example: \n"
+                               "  status and exec_time < 3.0"),
+                         default="status")
         parser.add_option_group(group)
 
         group = OptionGroup(parser, "Test tools")
@@ -213,6 +227,9 @@
                     "invalid --test-externals argument, does not exist: %r" % (
                         opts.test_suite_externals,))
 
+        if self.opts.single_result:
+            self.opts.only_test = os.path.dirname(self.opts.single_result)
+                
         opts.cmake = resolve_command_path(opts.cmake)
         if not isexecfile(opts.cmake):
             parser.error("CMake tool not found (looked for %s)" % opts.cmake)
@@ -465,6 +482,19 @@
             raw_name = test_data['name'].split(' :: ', 1)[1]
             name = 'nts.' + raw_name.rsplit('.test', 1)[0]
             is_pass = self._is_pass_code(test_data['code'])
+
+            # If --single-result is given, exit based on --single-result-predicate
+            if self.opts.single_result and \
+               raw_name == self.opts.single_result+'.test':
+                env = {'status': is_pass}
+                if 'metrics' in test_data:
+                    for k,v in test_data['metrics'].items():
+                        env[k] = v
+                        if k in LIT_METRIC_TO_LNT:
+                            env[LIT_METRIC_TO_LNT[k]] = v
+                status = eval(self.opts.single_result_predicate, {}, env)
+                sys.exit(0 if status else 1)
+
             if 'metrics' in test_data:
                 for k,v in test_data['metrics'].items():
                     if k not in LIT_METRIC_TO_LNT or LIT_METRIC_TO_LNT[k] in ignore:
@@ -487,6 +517,10 @@
                                             [self._get_lnt_code(test_data['code'])],
                                             test_info))
 
+        if self.opts.single_result:
+            # If we got this far, the result we were looking for didn't exist.
+            raise RuntimeError("Result %s did not exist!" %
+                               self.opts.single_result)
 
         # FIXME: Add more machine info!
         run_info = {