Teach nxdtest to run tests locally

It is very handy to debug both .nxdtest and nxdtest tool itself, and to
be able to run tests locally during development instead of (in addition
to) waiting for the test result from test nodes.

-> Teach nxdtest to run and report tests locally if no --master_url was
provided.

Idea is taken from runTestSuite.in from NEO, Cython+, Buildout and Rina:

https://lab.nexedi.com/nexedi/slapos/blob/3b14e028/software/neoppod/runTestSuite.in#L95-105
https://lab.nexedi.com/nexedi/slapos/blob/3b14e028/software/neoppod/runTestSuite.in#L55-75
https://lab.nexedi.com/nexedi/slapos/blob/3b14e028/software/neoppod/stress-testing/runTestSuite.in#L17-37
https://lab.nexedi.com/nexedi/slapos/blob/3b14e028/software/cython-test/runTestSuite.in#L38-58
https://lab.nexedi.com/nexedi/slapos/blob/3b14e028/software/buildout-testing/runTestSuite.in#L21-39
https://lab.nexedi.com/nexedi/slapos/blob/3b14e028/software/build-rina/runTestSuite.in#L29-49

Instead of copying code over and over again, let's stick to UNIX
approach and make it to be in one tool only that does its job
(hopefully) good.

nxdtest

@@ -46,6 +46,11 @@ step handled by SlapOS.
 (*) https://www.erp5.com/NXD-Presentation.ci.testing.system.buildout
     https://www.erp5.com/erp5-Guideline.Nexedi.Testing.Extended
     https://stack.nexedi.com/test_status
+
+Local mode
+----------
+
+Tests are run locally if --master_url option is not specified.
 """
 
 from __future__ import print_function, absolute_import
@@ -90,7 +95,7 @@ def main():
     # testnode executes us giving URL to master results collecting instance and other details
     # https://lab.nexedi.com/nexedi/erp5/blob/744f3fde/erp5/util/testnode/UnitTestRunner.py#L137
     parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
-    parser.add_argument('--master_url', help='The URL of Master controling many suites')
+    parser.add_argument('--master_url', help='The URL of Master controlling many suites (local run if not specified)')
     parser.add_argument('--revision', help='The revision to test', default='dummy_revision')
     parser.add_argument('--test_suite', help='The test suite name')
     parser.add_argument('--test_suite_title', help='The test suite title')
@@ -110,6 +115,8 @@ def main():
     # load list of tests to run
     tenv = loadNXDTestFile('.nxdtest')
 
+    # master_url provided -> run tests under master control
+    if args.master_url is not None:
         # connect to master and create 'test result' object with list of tests to run
         tool = TaskDistributor(portal_url = args.master_url, logger = logger)
         test_result = tool.createTestResult(
@@ -123,6 +130,10 @@ def main():
             # a test run for given name and revision has already been completed
             return
 
+    # master_url not provided -> run tests locally
+    else:
+        test_result = LocalTestResult(tenv)
+
     # make sure we get output from subprocesses without delay.
     # go does not buffer stdout/stderr by default, but python does for stdout.
     # tell python not to buffer anything.
@@ -230,6 +241,38 @@ def tee(fin, fout, buf):
 
 
 
+# LocalTestResult* handle tests runs, when master_url was not provided and tests are run locally.
+class LocalTestResult:
+    def __init__(self, tenv):
+        assert isinstance(tenv, TestEnv)
+        self.tenv = tenv
+        self.next = 0 # tenv.testv[next] is next test to execute
+
+    def start(self): # -> test_result_line
+        if self.next >= len(self.tenv.testv):
+            return None # all tests are done
+
+        test_result_line = LocalTestResultLine()
+        test_result_line.name = self.tenv.testv[self.next].name
+        self.next += 1
+        return test_result_line
+
+class LocalTestResultLine:
+    def stop(self, **kw):
+        def v(name):
+            return kw.get(name, '?')
+
+        _ = v('error_count')
+        if _ == '?':
+            st = '?'
+        elif _ == 0:
+            st = 'ok'
+        else:
+            st = 'fail'
+
+        print('%s\t%s\t%.3fs\t# %st %se %sf %ss' % (st, self.name, kw['duration'], v('test_count'), v('error_count'), v('failure_count'), v('skip_count')))
+        # XXX + dump .json ?
+
 
 if __name__ == '__main__':
     main()