How to use the sure.microseconds function in sure

def test_microsecond_unit():
    "testing microseconds convertion"
    cfrom, cto = sure.UNITS[sure.microsecond]

    assert_equals(cfrom(1), 100000)
    assert_equals(cto(1), 1)

    cfrom, cto = sure.UNITS[sure.microseconds]

    assert_equals(cfrom(1), 100000)
    assert_equals(cto(1), 1)

@within(two=microseconds)
def test_httpretty_should_mock_a_simple_get_with_requests_read(now):
    "HTTPretty should mock a simple GET with requests.get"

    HTTPretty.register_uri(HTTPretty.GET, "http://yipit.com/",
                           body="Find the best daily deals")

    response = requests.get('http://yipit.com')
    expect(response.text).to.equal('Find the best daily deals')
    expect(HTTPretty.last_request.method).to.equal('GET')
    expect(HTTPretty.last_request.path).to.equal('/')

@within(two=microseconds)
def test_httpretty_should_mock_a_simple_get_with_httplib2_read(now):
    "HTTPretty should mock a simple GET with httplib2.context.http"

    HTTPretty.register_uri(HTTPretty.GET, "http://yipit.com/",
                           body="Find the best daily deals")

    _, got = httplib2.Http().request('http://yipit.com', 'GET')
    expect(got).to.equal(b'Find the best daily deals')

    expect(HTTPretty.last_request.method).to.equal('GET')
    expect(HTTPretty.last_request.path).to.equal('/')

@within(two=microseconds)
def test_httpretty_should_allow_adding_and_overwritting_httplib2(now):
    "HTTPretty should allow adding and overwritting headers with httplib2"

    HTTPretty.register_uri(HTTPretty.GET, "http://github.com/foo",
                           body="this is supposed to be the response",
                           adding_headers={
                               'Server': 'Apache',
                               'Content-Length': '27',
                               'Content-Type': 'application/json',
                           })

    headers, _ = httplib2.Http().request('http://github.com/foo', 'GET')

    expect(dict(headers)).to.equal({
        'content-type': 'application/json',
        'content-location': 'http://github.com/foo',

@within(two=microseconds)
def test_httpretty_should_mock_headers_urllib2(now):
    "HTTPretty should mock basic headers with urllib2"

    HTTPretty.register_uri(HTTPretty.GET, "http://github.com/",
                           body="this is supposed to be the response",
                           status=201)

    request = urlopen('http://github.com')

    headers = dict(request.headers)
    request.close()

    request.code.should.equal(201)
    headers.should.equal({
        'content-type': 'text/plain; charset=utf-8',
        'connection': 'close',

@within(two=microseconds)
def test_httpretty_should_mock_a_simple_get_with_urllib2_read():
    "HTTPretty should mock a simple GET with urllib2.read()"

    HTTPretty.register_uri(HTTPretty.GET, "http://yipit.com/",
                           body="Find the best daily deals")

    fd = urlopen('http://yipit.com')
    got = fd.read()
    fd.close()

    got.should.equal(b'Find the best daily deals')

@within(two=microseconds)
def test_httpretty_should_allow_adding_and_overwritting_requests(now):
    "HTTPretty should allow adding and overwritting headers with requests"

    HTTPretty.register_uri(HTTPretty.GET, "http://github.com/foo",
                           body="this is supposed to be the response",
                           adding_headers={
                               'Server': 'Apache',
                               'Content-Length': '27',
                               'Content-Type': 'application/json',
                           })

    response = requests.get('http://github.com/foo')

    expect(dict(response.headers)).to.equal({
        'content-type': 'application/json',
        'connection': 'close',