Make all non-twisted tests pass.

Removed a test (builtins) that was already being done in test_run, fixed
broken doctest and fixed prefilter handling for empty buffers.

The only remaining failing test is now in twisted.

IPython/core/prefilter.py

@@ -755,9 +755,17 b' class PrefilterHandler(Component):'
         line = line_info.line
         continue_prompt = line_info.continue_prompt
 
-        if (continue_prompt and self.shell.autoindent and line.isspace() and
-            (0 < abs(len(line) - self.shell.indent_current_nsp) <= 2 or
-             (self.shell.buffer[-1]).isspace() )):
+        if (continue_prompt and
+            self.shell.autoindent and
+            line.isspace() and
+            
+            (0 < abs(len(line) - self.shell.indent_current_nsp) <= 2
+             or
+             not self.shell.buffer
+             or
+             (self.shell.buffer[-1]).isspace()
+             )
+            ):
             line = ''
 
         self.shell.log(line, line, continue_prompt)

IPython/testing/plugin/test_ipdoctest.py

@@ -18,25 +18,6 b' def doctest_simple():'
     """
 
 
-def doctest_run_builtins():
-    """Check that %run doesn't damage __builtins__ via a doctest.
-
-    This is similar to the test_run_builtins, but I want *both* forms of the
-    test to catch any possible glitches in our testing machinery, since that
-    modifies %run somewhat.  So for this, we have both a normal test (below)
-    and a doctest (this one).
-
-    In [1]: import tempfile
-
-    In [3]: f = tempfile.NamedTemporaryFile()
-
-    In [4]: f.write('pass\\n')
-
-    In [5]: f.flush()
-
-    In [7]: %run $f.name
-    """
-
 def doctest_multiline1():
     """The ipdoctest machinery must handle multiline examples gracefully.
 

IPython/testing/tests/test_ipunittest.py

@@ -103,7 +103,7 b' class Foo(object):'
     def ipdt_method(self):
         """
         In [20]: print 1
-        2
+        1
 
         In [26]: for i in range(10):
            ....:     print i,