Redirect luatest stderr to stdout with new option

By default, test-run captures the stderr stream and redirects its to the
log file:

    $ cat /tmp/t/001_foo-luatest/foo_test.log:
    [001] Some error log
    [001] My warning log
    ...

Use the new option `--show-capture` (abbr. `-c`) to redirect stderr to
stdout. Use it instead of the deprecated `--verbose` option.

The `--verbose` option will be ignored and output:

    Argument ['--verbose'] is deprecated and is ignored.

Close tarantool/luatest#308

lib/luatest_server.py

@@ -62,7 +62,10 @@ def execute(self, server):
         project_dir = os.environ['SOURCEDIR']
 
         with open(server.logfile, 'ab') as f:
-            proc = Popen(command, cwd=project_dir, stdout=sys.stdout, stderr=f)
+            stderr = f
+            if Options().args.show_capture:
+                stderr = sys.stdout
+            proc = Popen(command, cwd=project_dir, stdout=sys.stdout, stderr=stderr)
         sampler.register_process(proc.pid, self.id, server.name)
         test_timeout = Options().args.test_timeout
         timer = Timer(test_timeout, timeout_handler, (proc, test_timeout))

lib/options.py

@@ -37,6 +37,14 @@ def format_help(s):
     return textwrap.dedent(s.lstrip('\n')) + '\n'
 
 
+class DeprecationWarning(argparse._StoreTrueAction):
+    """Сustom definition of the 'store_true' procedure"""
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        color_stdout("Argument %s is deprecated and is ignored.\n" % self.option_strings, schema='info')
+        setattr(namespace, self.dest, values)
+
+
 class Options(object):
     """Handle options of test-runner"""
 
@@ -126,7 +134,7 @@ def __init__(self):
         parser.add_argument(
                 "--verbose",
                 dest='is_verbose',
-                action="store_true",
+                action=DeprecationWarning,
                 default=False,
                 help=format_help(
                     """
@@ -135,6 +143,18 @@ def __init__(self):
                     Default: false.
                     """))
 
+        parser.add_argument(
+                "-c", "--show-capture",
+                dest='show_capture',
+                action='store_true',
+                default=False,
+                help=format_help(
+                    """
+                    Whether to show captured TAP13 output or not.
+
+                    Default: false.
+                    """))
+
         parser.add_argument(
                 '--debug',
                 dest='debug',

lib/test.py

@@ -226,7 +226,7 @@ def run(self, server):
                 self.is_equal_result = filecmp.cmp(self.result,
                                                    self.tmp_result)
             elif self.is_executed_ok:
-                if Options().args.is_verbose:
+                if Options().args.show_capture:
                     color_stdout('\n')
                     with open(self.tmp_result, 'r') as f:
                         color_stdout(f.read(), schema='log')