add unit conversion test for pair style sw

            EXPECT_NEAR(ev_convert * fold[i][j], f[i][j], fabs(f[i][j] * rel_error));

}

TEST_F(PairUnitConvertTest, sw)

{

    // check if the prerequisite pair style is available

    if (!info->has_style("pair", "sw")) GTEST_SKIP();

    if (!verbose) ::testing::internal::CaptureStdout();

    lmp->input->one("units metal");

    lmp->input->one("read_data test_pair_unit_convert.data");

    lmp->input->one("pair_style sw");

    lmp->input->one("pair_coeff * * GaN.sw Ga N");

    lmp->input->one("run 0 post no");

    if (!verbose) ::testing::internal::GetCapturedStdout();

    // copy energy and force from first step

    double eold = lmp->force->pair->eng_vdwl + lmp->force->pair->eng_coul;

    double **f  = lmp->atom->f;

    for (int i = 0; i < 4; ++i)

        for (int j = 0; j < 3; ++j)

            fold[i][j] = f[i][j];

    if (!verbose) ::testing::internal::CaptureStdout();

    lmp->input->one("clear");

    lmp->input->one("units real");

    lmp->input->one("read_data test_pair_unit_convert.data");

    lmp->input->one("pair_style sw");

    lmp->input->one("pair_coeff * * GaN.sw Ga N");

    lmp->input->one("run 0 post no");

    if (!verbose) ::testing::internal::GetCapturedStdout();

    double enew = lmp->force->pair->eng_vdwl + lmp->force->pair->eng_coul;

    EXPECT_NEAR(ev_convert * eold, enew, fabs(enew * rel_error));

    f = lmp->atom->f;

    for (int i = 0; i < 4; ++i)

        for (int j = 0; j < 3; ++j)

            EXPECT_NEAR(ev_convert * fold[i][j], f[i][j], fabs(f[i][j] * rel_error));

}

} // namespace LAMMPS_NS

int main(int argc, char **argv)