import sh
import unittest


class Qeeprom(unittest.TestCase):

    __position = None
    __uuid = None
    __eeprompath = None

    # varlist: position, uuid, eeprompath
    def __init__(self, testname, testfunc, varlist):
        super(Qeeprom, self).__init__(testfunc)
        self._testMethodDoc = testname
        if "position" in varlist:
            self.__position = varlist["position"]
        else:
            raise Exception('position param inside Qeeprom must be defined')
        if "uuid" in varlist:
            self.__uuid = varlist["uuid"]
        else:
            raise Exception('uuid param inside Qeeprom must be defined')
        if "eeprompath" in varlist:
            self.__eeprompath = varlist["eeprompath"]
        else:
            raise Exception('eeprompath param inside Qeeprom must be defined')

    def execute(self):
        # write data into the eeprom
        p = sh.dd(sh.echo(self._uuid), "of=" + self.__eeprompath, "bs=1", "seek=" + self.__position)
        if p.exit_code == 0:
            # read data from the eeprom
            p = sh.dd("if=" + self.__eeprompath, "bs=1", "skip=" + self.__position, "count=" + len(self.__uuid))
            if p.exit_code == 0:
                uuid_rx = p.stdout.decode('ascii')
                # compare both values
                if (uuid_rx != self.__uuid):
                    self.fail("failed: mismatch between written and received values.")

            else:
                self.fail("failed: Unable to read from the EEPROM device.")
        else:
            self.fail("failed: Unable to write on the EEPROM device.")