anchor.diff:      };
     };
   
  +  # Special check phase for numpy and scipy, following the same set of steps:
  +  # First "install" the package, then import what was installed, and call the
  +  # .test() function, which will run the test suite.
  +  numpyScipyCheckPhase = python: pkgName: ''
  +    runHook preCheck
  +
  +    _python=${python}/bin/${python.executable}
  +
  +    # We will "install" into a temp directory, so that we can run the numpy
  +    # tests (see below).
  +    install_dir="$TMPDIR/test_install"
  +    install_lib="$install_dir/lib/${python.libPrefix}/site-packages"
  +    mkdir -p $install_dir
  +    $_python setup.py install \
  +      --install-lib=$install_lib \
  +      --old-and-unmanageable \
  +      --prefix=$install_dir > /dev/null
  +
  +    # Create a directory in which to run tests (you get an error if you try to
  +    # import the package when you're in the current directory).
  +    mkdir $TMPDIR/run_tests
  +    pushd $TMPDIR/run_tests > /dev/null
  +    # Temporarily add the directory we installed in to the python path
  +    # (not permanently, or this pythonpath will wind up getting exported),
  +    # and run the test suite.
  +    PYTHONPATH="$install_lib:$PYTHONPATH" $_python -c \
  +      'import ${pkgName}; ${pkgName}.test("fast", verbose=10)'
  +    popd > /dev/null
  +
  +    runHook postCheck
  +  '';
  +
  +  # Special prebuild step for numpy and scipy. Creates a site.cfg telling
  +  # the setup script where to find depended-on math libraries.
  +  numpyScipyPrebuild = ''
  +    echo "Creating site.cfg file..."
  +    cat << EOF > site.cfg
  +    [atlas]
  +    include_dirs = ${pkgs.atlasWithLapack}/include
  +    library_dirs = ${pkgs.atlasWithLapack}/lib
  +    EOF
  +  '';
  +
     numpy = buildPythonPackage ( rec {
       name = "numpy-1.9.2";
   
  
positive.code:       sha256 = "16i5iksaas3m0hgbxrxpgsyri4a9ncbwbiazlhx5d6lynz1wn4m2";
      };
  
      buildInputs = [ pkgs.gfortran ];
      propagatedBuildInputs = with self; [ numpy ];
  
      # TODO: add ATLAS=${pkgs.atlas}
      preConfigure = ''
        export BLAS=${pkgs.blas} LAPACK=${pkgs.liblapack}
        sed -i '0,/from numpy.distutils.core/s//import setuptools;from numpy.distutils.core/' setup.py
      '';
  
      setupPyBuildFlags = [ "--fcompiler='gnu95'" ];
  
      # error: invalid command 'test'
      doCheck = false;
  
      meta = {
        description = "SciPy (pronounced 'Sigh Pie') is open-source software for mathematics, science, and engineering. ";
  
negative.code:       sed -i '0,/from numpy.distutils.core/s//import setuptools;from numpy.distutils.core/' setup.py
      '';
  
      preBuild = self.numpyScipyPrebuild;
  
      setupPyBuildFlags = ["--fcompiler='gnu95'"];
  
      buildInputs = [ pkgs.gfortran self.nose ];
      propagatedBuildInputs = [ pkgs.atlas ];
  
      checkPhase = self.numpyScipyCheckPhase python "numpy";
  
      meta = {
        description = "Scientific tools for Python";
  