Make testing easier by exposing a top-level test() function.

Fixes https://bugs.launchpad.net/ipython/+bug/504450

IPython/__init__.py

@@ -42,6 +42,7 b' sys.path.append(os.path.join(os.path.dirname(__file__), "extensions"))'
 from IPython.core.iplib import InteractiveShell
 from IPython.core.embed import embed
 from IPython.core.error import TryNext
+from IPython.testing import test
 
 from IPython.lib import (
     enable_wx, disable_wx,
@@ -61,4 +62,3 b' for author, email in release.authors.values():'
 __license__  = release.license
 __version__  = release.version
 __revision__ = release.revision
-

IPython/testing/__init__.py

@@ -0,0 +1,18 b''
+"""Testing support (tools to test IPython itself).
+"""
+
+# User-level entry point for testing
+def test():
+    """Run the entire IPython test suite.
+
+    For fine-grained control, you should use the :file:`iptest` script supplied
+    with the IPython installation."""
+
+    # Do the import internally, so that this function doesn't increase total
+    # import time
+    from iptest import run_iptestall
+    run_iptestall()
+
+# So nose doesn't try to run this as a test itself and we end up with an
+# infinite test loop
+test.__test__ = False