#1478 Add --show-capture option

_pytest/terminal.py

@@ -42,6 +42,11 @@ def pytest_addoption(parser):
                      action="store", dest="tbstyle", default='auto',
                      choices=['auto', 'long', 'short', 'no', 'line', 'native'],
                      help="traceback print mode (auto/long/short/line/native/no).")
+    group._addoption('--show-capture',
+                     action="store", dest="showcapture",
+                     choices=['no', 'stdout', 'stderr', 'both'], default='both',
+                     help="Controls how captured stdout/stderr is shown on failed tests. "
+                          "Default is 'both'.")
     group._addoption('--fulltrace', '--full-trace',
                      action="store_true", default=False,
                      help="don't cut any tracebacks (default is to cut).")
@@ -622,7 +627,12 @@ def summary_errors(self):
 
     def _outrep_summary(self, rep):
         rep.toterminal(self._tw)
+        if self.config.option.showcapture == 'no':
+            return
         for secname, content in rep.sections:
+            if self.config.option.showcapture != 'both':
+                if not (self.config.option.showcapture in secname):
+                    continue
             self._tw.sep("-", secname)
             if content[-1:] == "\n":
                 content = content[:-1]

changelog/1478.feature

@@ -0,0 +1 @@
+New ``--show-capture`` command-line option that allows to specify how to display captured output when tests fail: ``no``, ``stdout``, ``stderr`` or ``both`` (the default).

doc/en/capture.rst

@@ -9,7 +9,8 @@ Default stdout/stderr/stdin capturing behaviour
 
 During test execution any output sent to ``stdout`` and ``stderr`` is
 captured.  If a test or a setup method fails its according captured
-output will usually be shown along with the failure traceback.
+output will usually be shown along with the failure traceback. (this
+behavior can be configured by the ``--show-capture`` command-line option).
 
 In addition, ``stdin`` is set to a "null" object which will
 fail on attempts to read from it because it is rarely desired

testing/test_terminal.py

@@ -823,6 +823,35 @@ def pytest_report_header(config, startdir):
             str(testdir.tmpdir),
         ])
 
+    def test_show_capture(self, testdir):
+        testdir.makepyfile("""
+            import sys
+            def test_one():
+                sys.stdout.write('!This is stdout!')
+                sys.stderr.write('!This is stderr!')
+                assert False, 'Something failed'
+        """)
+
+        result = testdir.runpytest("--tb=short")
+        result.stdout.fnmatch_lines(["!This is stdout!"])
+        result.stdout.fnmatch_lines(["!This is stderr!"])
+
+        result = testdir.runpytest("--show-capture=both", "--tb=short")
+        result.stdout.fnmatch_lines(["!This is stdout!"])
+        result.stdout.fnmatch_lines(["!This is stderr!"])
+
+        result = testdir.runpytest("--show-capture=stdout", "--tb=short")
+        assert "!This is stderr!" not in result.stdout.str()
+        assert "!This is stdout!" in result.stdout.str()
+
+        result = testdir.runpytest("--show-capture=stderr", "--tb=short")
+        assert "!This is stdout!" not in result.stdout.str()
+        assert "!This is stderr!" in result.stdout.str()
+
+        result = testdir.runpytest("--show-capture=no", "--tb=short")
+        assert "!This is stdout!" not in result.stdout.str()
+        assert "!This is stderr!" not in result.stdout.str()
+
 
 @pytest.mark.xfail("not hasattr(os, 'dup')")
 def test_fdopen_kept_alive_issue124(testdir):