import numpy as np
import tempfile

from numpy.testing import assert_array_almost_equal, run_module_suite, assert_

from scipy.sparse import csc_matrix, csr_matrix, bsr_matrix, dia_matrix, coo_matrix, save_npz, load_npz


def _save_and_load(matrix):        
    with tempfile.NamedTemporaryFile(suffix='.npz') as file:
        file = file.name
        save_npz(file, matrix)
        loaded_matrix = load_npz(file)
    return loaded_matrix

def _check_save_and_load(dense_matrix):
    for matrix_class in [csc_matrix, csr_matrix, bsr_matrix, dia_matrix, coo_matrix]:
        matrix = matrix_class(dense_matrix)
        loaded_matrix = _save_and_load(matrix)
        assert_(type(loaded_matrix) is matrix_class)
        assert_(loaded_matrix.shape == dense_matrix.shape)
        assert_(loaded_matrix.dtype == dense_matrix.dtype)
        assert_array_almost_equal(loaded_matrix.toarray(), dense_matrix)

def test_save_and_load_random():
    N = 10
    np.random.seed(0)
    dense_matrix = np.random.random((N, N))
    dense_matrix[dense_matrix > 0.7] = 0
    _check_save_and_load(dense_matrix)

def test_save_and_load_empty():
    dense_matrix = np.zeros((4,6))
    _check_save_and_load(dense_matrix)

def test_save_and_load_one_entry():
    dense_matrix = np.zeros((4,6))
    dense_matrix[1,2] = 1
    _check_save_and_load(dense_matrix)


if __name__ == "__main__":
    run_module_suite()
