oeqa/concurrencytest: Fix display of test stdout/stderr

If oe-selftest is run with -j, the output to stdout/stderr is being
lost at present. Capture this and display it upon test failure. We
have code that previously tried to enable this but it wasn't functioning
correctly. This should give more usable error reports on the autobuilder.

This code will mix stdout and stderr as the output is streamed from the test
server without markup. This is most in keeping with subunit/testools though
and the easiest way to handle the various challenges here as far as I can
see.

(From OE-Core rev: 6a954ce5834c8026adecff8478c3d827640bc647)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/core/utils/concurrencytest.py

@@ -48,11 +48,15 @@ _all__ = [
 #
 class BBThreadsafeForwardingResult(ThreadsafeForwardingResult):
 
-    def __init__(self, target, semaphore, threadnum, totalinprocess, totaltests):
+    def __init__(self, target, semaphore, threadnum, totalinprocess, totaltests, output, finalresult):
         super(BBThreadsafeForwardingResult, self).__init__(target, semaphore)
         self.threadnum = threadnum
         self.totalinprocess = totalinprocess
         self.totaltests = totaltests
+        self.buffer = True
+        self.outputbuf = output
+        self.finalresult = finalresult
+        self.finalresult.buffer = True
 
     def _add_result_with_semaphore(self, method, test, *args, **kwargs):
         self.semaphore.acquire()
@@ -71,6 +75,8 @@ class BBThreadsafeForwardingResult(ThreadsafeForwardingResult):
                     test.id())
         finally:
             self.semaphore.release()
+        self.finalresult._stderr_buffer = io.StringIO(initial_value=self.outputbuf.getvalue().decode("utf-8"))
+        self.finalresult._stdout_buffer = io.StringIO()
         super(BBThreadsafeForwardingResult, self)._add_result_with_semaphore(method, test, *args, **kwargs)
 
 class ProxyTestResult:
@@ -196,19 +202,11 @@ class ConcurrentTestSuite(unittest.TestSuite):
             queue = Queue()
             semaphore = threading.Semaphore(1)
             result.threadprogress = {}
-            for i, (testserver, testnum) in enumerate(testservers):
+            for i, (testserver, testnum, output) in enumerate(testservers):
                 result.threadprogress[i] = []
                 process_result = BBThreadsafeForwardingResult(
                         ExtraResultsDecoderTestResult(result),
-                        semaphore, i, testnum, totaltests)
-                # Force buffering of stdout/stderr so the console doesn't get corrupted by test output
-                # as per default in parent code
-                process_result.buffer = True
-                # We have to add a buffer object to stdout to keep subunit happy
-                process_result._stderr_buffer = io.StringIO()
-                process_result._stderr_buffer.buffer = dummybuf(process_result._stderr_buffer)
-                process_result._stdout_buffer = io.StringIO()
-                process_result._stdout_buffer.buffer = dummybuf(process_result._stdout_buffer)
+                        semaphore, i, testnum, totaltests, output, result)
                 reader_thread = threading.Thread(
                     target=self._run_test, args=(testserver, process_result, queue))
                 threads[testserver] = reader_thread, process_result
@@ -273,10 +271,11 @@ def fork_for_tests(concurrency_num, suite):
                 newsi = os.open(os.devnull, os.O_RDWR)
                 os.dup2(newsi, sys.stdin.fileno())
 
+                # Send stdout/stderr over the stream
+                os.dup2(c2pwrite, sys.stdout.fileno())
+                os.dup2(c2pwrite, sys.stderr.fileno())
+
                 subunit_client = TestProtocolClient(stream)
-                # Force buffering of stdout/stderr so the console doesn't get corrupted by test output
-                # as per default in parent code
-                subunit_client.buffer = True
                 subunit_result = AutoTimingTestResultDecorator(subunit_client)
                 unittest_result = process_suite.run(ExtraResultsEncoderTestResult(subunit_result))
                 if ourpid != os.getpid():
@@ -306,8 +305,10 @@ def fork_for_tests(concurrency_num, suite):
         else:
             os.close(c2pwrite)
             stream = os.fdopen(c2pread, 'rb', 1)
-            testserver = ProtocolTestCase(stream)
-            testservers.append((testserver, numtests))
+            # Collect stdout/stderr into an io buffer
+            output = io.BytesIO()
+            testserver = ProtocolTestCase(stream, passthrough=output)
+            testservers.append((testserver, numtests, output))
     return testservers, totaltests
 
 def partition_tests(suite, count):