Show BDD scenario on failed tests

See #1552

qutebrowser/utils/log.py

@@ -38,6 +38,10 @@ except ImportError:
     colorama = None
 
 COLORS = ['black', 'red', 'green', 'yellow', 'blue', 'purple', 'cyan', 'white']
+COLOR_ESCAPES = {color: '\033[{}m'.format(i)
+                 for i, color in enumerate(COLORS, start=30)}
+RESET_ESCAPE = '\033[0m'
+
 
 # Log formats to use.
 SIMPLE_FMT = ('{green}{asctime:8}{reset} {log_color}{levelname}{reset}: '
@@ -473,28 +477,20 @@ class ColoredFormatter(logging.Formatter):
 
     Attributes:
         use_colors: Whether to do colored logging or not.
-
-    Class attributes:
-        COLOR_ESCAPES: A dict mapping color names to escape sequences
-        RESET_ESCAPE: The escape sequence using for resetting colors
     """
 
-    COLOR_ESCAPES = {color: '\033[{}m'.format(i)
-                     for i, color in enumerate(COLORS, start=30)}
-    RESET_ESCAPE = '\033[0m'
-
     def __init__(self, fmt, datefmt, style, *, use_colors):
         super().__init__(fmt, datefmt, style)
         self._use_colors = use_colors
 
     def format(self, record):
         if self._use_colors:
-            color_dict = dict(self.COLOR_ESCAPES)
+            color_dict = dict(COLOR_ESCAPES)
-            color_dict['reset'] = self.RESET_ESCAPE
+            color_dict['reset'] = RESET_ESCAPE
             log_color = LOG_COLORS[record.levelname]
-            color_dict['log_color'] = self.COLOR_ESCAPES[log_color]
+            color_dict['log_color'] = COLOR_ESCAPES[log_color]
         else:
-            color_dict = {color: '' for color in self.COLOR_ESCAPES}
+            color_dict = {color: '' for color in COLOR_ESCAPES}
             color_dict['reset'] = ''
             color_dict['log_color'] = ''
         record.__dict__.update(color_dict)

tests/end2end/features/conftest.py

@@ -20,6 +20,7 @@
 """Steps for bdd-like tests."""
 
 import re
+import sys
 import time
 import json
 import os.path
@@ -30,9 +31,69 @@ import textwrap
 import pytest
 import pytest_bdd as bdd
 
+from qutebrowser.utils import log
 from helpers import utils
 
 
+@pytest.hookimpl(hookwrapper=True)
+def pytest_runtest_makereport(item, call):
+    """Add a BDD section to the test output."""
+    outcome = yield
+    if call.when not in ['call', 'teardown']:
+        return
+    report = outcome.get_result()
+
+    if report.passed:
+        return
+
+    if not hasattr(report.longrepr, 'addsection'):
+        # In some conditions (on OS X and Windows it seems), report.longrepr is
+        # actually a tuple. This is handled similarily in pytest-qt too.
+        return
+
+    if sys.stdout.isatty() and item.config.getoption('--color') != 'no':
+        colors = {
+            'failed': log.COLOR_ESCAPES['red'],
+            'passed': log.COLOR_ESCAPES['green'],
+            'keyword': log.COLOR_ESCAPES['cyan'],
+            'reset': log.RESET_ESCAPE,
+        }
+    else:
+        colors = {
+            'failed': '',
+            'passed': '',
+            'keyword': '',
+            'reset': '',
+        }
+
+    output = []
+    output.append("{kw_color}Feature:{reset} {name}".format(
+        kw_color=colors['keyword'],
+        name=report.scenario['feature']['name'],
+        reset=colors['reset'],
+    ))
+    output.append("  {kw_color}Scenario:{reset} {name} "
+                  "({filename}:{line})".format(
+        kw_color=colors['keyword'],
+        name=report.scenario['name'],
+        filename=report.scenario['feature']['rel_filename'],
+        line=report.scenario['line_number'],
+        reset=colors['reset'],
+    ))
+    for step in report.scenario['steps']:
+        output.append("    {kw_color}{keyword}{reset} {color}{name}{reset} "
+                      "({duration:.2f}s)".format(
+            kw_color=colors['keyword'],
+            color=colors['failed'] if step['failed'] else colors['passed'],
+            keyword=step['keyword'],
+            name=step['name'],
+            duration=step['duration'],
+            reset=colors['reset'],
+        ))
+
+    report.longrepr.addsection("BDD scenario", '\n'.join(output))
+
+
 ## Given