@@ -114,6 +114,9 @@ Other Changes and Additions
 - ``ConfigurationItem``\s now have a more useful and informative ``__repr__``
   and improved documentation for how to use them. [#855]
 
+- Added a friendlier error message when trying to import astropy from a source
+  checkout without first building the extension modules inplace. [#864]
+
 - ``py.test`` now outputs more system information for help in debugging issues
   from users. [#869]
 
 
@@ -121,8 +121,24 @@ def test(package=None, test_path=None, args=None, plugins=None,
     from . import config
 
     import os
+    import sys
     from warnings import warn
 
+    try:
+        from .utils import _compiler
+    except ImportError:
+        if os.path.exists('setup.py'):
+            log.error('You appear to be trying to import astropy from within '
+                      'a source checkout; please run `./setup.py develop` or '
+                      '`./setup.py --inplace` first so that extension '
+                      'modules can be compiled and made importable.')
+            sys.exit(1)
+        else:
+            # Outright broken installation; don't be nice.
+            raise
+
+
+
     # add these here so we only need to cleanup the namespace at the end
     config_dir = None