Improve display of continuation lines with multiline errors

Fixes pytest-dev#717.
Follow-up to pytest-dev#1762.

Author: blueyed

CHANGELOG.rst

@@ -3,9 +3,10 @@
 
 **Bug Fixes**
 
-* Add an 'E' to the first line of error messages from FixtureLookupErrorRepr.
-  Fixes `#717`_. Thanks `@blueyed`_ for reporting, `@eolo999`_ for the PR
-  and `@tomviner`_ for his guidance during EuroPython2016 sprint.
+* Improve error message with fixture lookup errors: add an 'E' to the first
+  line and '>' to the rest. Fixes `#717`_. Thanks `@blueyed`_ for reporting and
+  a PR, `@eolo999`_ for the initial PR and `@tomviner`_ for his guidance during
+  EuroPython2016 sprint.
 
 * Text documents without any doctests no longer appear as "skipped".
   Thanks `@graingert`_ for reporting and providing a full PR (`#1580`_).

_pytest/python.py

@@ -9,7 +9,7 @@
 
 import py
 import pytest
-from _pytest._code.code import TerminalRepr
+from _pytest._code.code import FormattedExcinfo, TerminalRepr
 from _pytest.mark import MarkDecorator, MarkerError
 
 try:
@@ -1849,12 +1849,12 @@ def toterminal(self, tw):
         for tbline in self.tblines:
             tw.line(tbline.rstrip())
         lines = self.errorstring.split("\n")
-        for line in lines:
-            if line == lines[0]:
-                prefix = 'E       '
-            else:
-                prefix = '        '
-            tw.line(prefix + line.strip(), red=True)
+        if lines:
+            tw.line('{}       {}'.format(FormattedExcinfo.fail_marker,
+                                         lines[0].strip()), red=True)
+            for line in lines[1:]:
+                tw.line('{}       {}'.format(FormattedExcinfo.flow_marker,
+                                             line.strip()), red=True)
         tw.line()
         tw.line("%s:%d" % (self.filename, self.firstlineno+1))
 

testing/python/fixture.py

@@ -395,10 +395,11 @@ def test_lookup_error(unknown):
         """)
         result = testdir.runpytest()
         result.stdout.fnmatch_lines([
-            "*ERROR*test_lookup_error*",
-            "*def test_lookup_error(unknown):*",
-            "*fixture*unknown*not found*",
-            "*available fixtures*",
+            "*ERROR at setup of test_lookup_error*",
+            "  def test_lookup_error(unknown):*",
+            "E       fixture 'unknown' not found",
+            ">       available fixtures:*",
+            ">       use 'py*test --fixtures *' for help on them.",
             "*1 error*",
         ])
         assert "INTERNAL" not in result.stdout.str()