Fix order of arguments in assertEqual

Some tests used incorrect order assertEqual(observed, expected).

The correct order expected by testtools is...

    def assertEqual(self, expected, observed, message=''):
        """Assert that 'expected' is equal to 'observed'.

        :param expected: The expected value.
        :param observed: The observed value.
        :param message: An optional message to include in the error.
        """

The string length of the sum of the results of repr(expected) and
repr(observed) is greater than 70, then, MismatchError message is
changed, as below.

  Ex.:
        raise mismatch_error
    MismatchError: !=:
    reference = '_123456789_123456789_bar'
    actual    = '_123456789_123456789_123456789_123456789_123456789'

Change-Id: Id02ddfb2ca03df7f432cff67a7bed182cccc4924
Closes-Bug: #1259292
convert availability zone tests to requests-mock

Blueprint: http-mock-testing
Change-Id: Ib02db9b9e24808d2f5eac42cf6f5b3c5ca123e9b
Updated from global requirements

Change-Id: I8d7b21b4ac55e9f02f067e31ad09a99b95180c4e
Merge "Fix order of arguments in assertEqual"
Merge "convert availability zone tests to requests-mock"
Merge "Updated from global requirements"