Emit run summary at the end

Sometimes there is zero testcases to be executed on testnodes, and
log output from nxdtest is just

    date:   Wed, 10 Nov 2021 12:31:50 MSK
    xnode:  kirr@deca.navytux.spb.ru
    uname:  Linux deca 5.10.0-9-amd64 #1 SMP Debian 5.10.70-1 (2021-09-30) x86_64
    cpu:    Intel(R) Core(TM) i7-7600U CPU @ 2.80GHz

it is not clear from such output did the run ended or the test got
stuck. After this patch it becomes

    date:   Wed, 10 Nov 2021 12:31:50 MSK
    xnode:  kirr@deca.navytux.spb.ru
    uname:  Linux deca 5.10.0-9-amd64 #1 SMP Debian 5.10.70-1 (2021-09-30) x86_64
    cpu:    Intel(R) Core(TM) i7-7600U CPU @ 2.80GHz
    # ran 0 test cases.

And in general, when there are several testcases to be run, it is helpful to
indicate end of such run and to print brief summary of result status for all
ran test cases. Example output:

    wendelin.core$ nxdtest -k test.wcfs
    date:   Wed, 10 Nov 2021 12:35:34 MSK
    xnode:  kirr@deca.navytux.spb.ru
    uname:  Linux deca 5.10.0-9-amd64 #1 SMP Debian 5.10.70-1 (2021-09-30) x86_64
    cpu:    Intel(R) Core(TM) i7-7600U CPU @ 2.80GHz
    >>> test.wcfs/fs:1
    ...
    ok      test.wcfs/fs:1  25.035s # 35t 0e 0f 0s

    >>> test.wcfs/fs:2
    ...
    ok      test.wcfs/fs:2  21.033s # 35t 0e 0f 0s

    >>> test.wcfs/fs:
    ...
    ok      test.wcfs/fs:   21.056s # 35t 0e 0f 0s
    # ran 3 test cases:  3·ok

/reviewed-by @jerome
/reviewed-on !12

nxdtest/__init__.py

@@ -61,7 +61,7 @@ from time import time, sleep, strftime, gmtime, localtime
 import os, sys, argparse, logging, traceback, re, pwd, socket
 from errno import ESRCH, EPERM
 import six
-from golang import b, select, default
+from golang import b, defer, func, select, default
 from golang import context, sync
 import psutil
 
@@ -111,6 +111,7 @@ def emit(*message):
   print(*message)
   sys.stdout.flush()
 
+@func
 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
@@ -183,6 +184,29 @@ def main():
       bstdout = sys.stdout.buffer
       bstderr = sys.stderr.buffer
 
+    # emit run summary at the end
+    summaryv = [] # of summary line for each ran testcase
+    def _():
+        stat = {} # st -> count
+        for line in summaryv:
+            st, _ = line.split(None, 1) # 'ok testname ...' -> 'ok'
+            stat[st] = stat.get(st, 0) + 1
+
+        s = '# ran %d test case' % len(summaryv)
+        if len(summaryv) == 0:
+            s += 's.'
+        else:
+            if len(summaryv) > 1:
+                s += 's'
+            s += ':'
+            # ok, fail, error go in that order
+            for st in ('ok', 'fail', 'error') + tuple(stat.keys()):
+                n = stat.pop(st, 0)
+                if n != 0:
+                    s += '  %d·%s' % (n, st)
+        emit(s)
+    defer(_)
+
     # run the tests
     devnull = open(os.devnull)
     while 1:
@@ -299,7 +323,9 @@ def main():
         }
         tres.update(status)
 
-        emit(_test_result_summary(t.name, tres))
+        _ = _test_result_summary(t.name, tres)
+        summaryv.append(_)
+        emit(_)
         test_result_line.stop(**tres)
 
 # tee, similar to tee(1) utility, copies data from fin to fout appending them to buf.

nxdtest/nxdtest_test.py

@@ -64,7 +64,8 @@ TestCase('TESTNAME', ['echo', 'TEST OUPUT'])
     assert ">>> TESTNAME" in output_lines
     assert "$ echo TEST OUPUT" in output_lines
     assert "TEST OUPUT" in output_lines
-    assert re.match("ok\tTESTNAME\t.*s\t# 1t 0e 0f 0s", output_lines[-1])
+    assert re.match("ok\tTESTNAME\t.*s\t# 1t 0e 0f 0s", output_lines[-2])
+    assert re.match(u"# ran 1 test case:  1·ok", output_lines[-1])
 
 
 def test_error_invoking_command(run_nxdtest, capsys):