merge from master to features

2 files changed, 5 insertions, 33 deletions

diff --git a/_pytest/assertion/rewrite.py b/_pytest/assertion/rewrite.py
index 921d17a10..06944b016 100644
--- a/_pytest/assertion/rewrite.py
+++ b/_pytest/assertion/rewrite.py
@@ -1,6 +1,7 @@
 """Rewrite assertion AST to produce nice error messages"""
 
 import ast
+import _ast
 import errno
 import itertools
 import imp
@@ -876,6 +877,8 @@ class AssertionRewriter(ast.NodeVisitor):
     def visit_Compare(self, comp):
         self.push_format_context()
         left_res, left_expl = self.visit(comp.left)
+        if isinstance(comp.left, (_ast.Compare, _ast.BoolOp)):
+            left_expl = "({0})".format(left_expl)
         res_variables = [self.variable() for i in range(len(comp.ops))]
         load_names = [ast.Name(v, ast.Load()) for v in res_variables]
         store_names = [ast.Name(v, ast.Store()) for v in res_variables]
@@ -885,6 +888,8 @@ class AssertionRewriter(ast.NodeVisitor):
         results = [left_res]
         for i, op, next_operand in it:
             next_res, next_expl = self.visit(next_operand)
+            if isinstance(next_operand, (_ast.Compare, _ast.BoolOp)):
+                next_expl = "({0})".format(next_expl)
             results.append(next_res)
             sym = binop_map[op.__class__]
             syms.append(ast.Str(sym))
diff --git a/_pytest/assertion/util.py b/_pytest/assertion/util.py
index 8bf425caf..2481cf34c 100644
--- a/_pytest/assertion/util.py
+++ b/_pytest/assertion/util.py
@@ -38,44 +38,11 @@ def format_explanation(explanation):
     displaying diffs.
     """
     explanation = ecu(explanation)
-    explanation = _collapse_false(explanation)
     lines = _split_explanation(explanation)
     result = _format_lines(lines)
     return u('\n').join(result)
 
 
-def _collapse_false(explanation):
-    """Collapse expansions of False
-
-    So this strips out any "assert False\n{where False = ...\n}"
-    blocks.
-    """
-    where = 0
-    while True:
-        start = where = explanation.find("False\n{False = ", where)
-        if where == -1:
-            break
-        level = 0
-        prev_c = explanation[start]
-        for i, c in enumerate(explanation[start:]):
-            if prev_c + c == "\n{":
-                level += 1
-            elif prev_c + c == "\n}":
-                level -= 1
-                if not level:
-                    break
-            prev_c = c
-        else:
-            raise AssertionError("unbalanced braces: %r" % (explanation,))
-        end = start + i
-        where = end
-        if explanation[end - 1] == '\n':
-            explanation = (explanation[:start] + explanation[start+15:end-1] +
-                           explanation[end+1:])
-            where -= 17
-    return explanation
-
-
 def _split_explanation(explanation):
     """Return a list of individual lines in the explanation