def test_range_parse():
    assert isinstance(Range.parse("bytes=0-99"), Range)
    assert isinstance(Range.parse("BYTES=0-99"), Range)
    assert isinstance(Range.parse("bytes = 0-99"), Range)
    assert isinstance(Range.parse("bytes=0 - 102"), Range)
    assert Range.parse("bytes=10-5") is None
    assert Range.parse("bytes 5-10") is None
    assert Range.parse("words=10-5") is None

def test_parse_bytes_start_greater_than_end():
    range = Range(((0, 100),))
    assert_equal(range.parse_bytes("bytes=99-0"), None)

def test_parse_range_values():
    from webob.byterange import Range
    range = Range.parse("bytes=1-500")
    assert range.start == 1
    assert range.end == 501

def test_range_start_none():
    # Start is None
    range = Range(None, 99)
    assert range.range_for_length(100) is None

def test_range_for_length_end_is_none():
    # End is None
    range = Range(0, None)
    assert range.range_for_length(100) == (0, 100)

def test_range_repr():
    range = Range(0, 99)
    assert_true(range.__repr__(), '<Range bytes 0-98>')

def test_range_for_length_end_is_none():
    # End is None
    range = Range(0, None)
    eq_(range.range_for_length(100), (0,100))

def test_range_for_length_end_is_none():
    # End is None
    range = Range(((0, None),))
    assert_equal(range.range_for_length(100), (0, 100))

def test_range_for_length_one_range_and_length_none():
    # One range and length is None
    range = Range(((0, 99),))
    assert_equal(range.range_for_length(None), None)

def test_range_for_length_more_than_one_range():
    # More than one range
    range = Range(((0, 99), (100, 199)))
    assert_equal(range.range_for_length(100), None)

def test_range_content_range_length_ok():
    range = Range(((0, 100),))
    assert_true(range.content_range(100).__class__, ContentRange)

def test_range_content_range_length_none():
    range = Range(((0, 100),))
    assert_equal(range.content_range(None), None)

def test_parse_bytes_only_start():
    range = Range(((0, 100),))
    assert_equal(range.parse_bytes("bytes=0-"), ("bytes", [(0, None)]))

def test_parse_bytes_start_greater_than_last_end():
    range = Range(((0, 100),))
    assert_equal(range.parse_bytes("bytes=0-99,0-199"), None)

def test_range_for_length_end_is_none_negative_start():
    # End is None and start is negative
    range = Range(((-5, None),))
    assert_equal(range.range_for_length(100), (95, 100))

def test_range_content_range_length_none():
    range = Range(0, 100)
    eq_(range.content_range(None), None)
    assert isinstance(range.content_range(1), ContentRange)
    eq_(tuple(range.content_range(1)), (0,1,1))
    eq_(tuple(range.content_range(200)), (0,100,200))

def test_range_start_none():
    # Start is None
    range = Range(((None, 99),))
    assert_equal(range.range_for_length(100), None)

def test_range_start_none():
    # Start is None
    range = Range(None, 99)
    eq_(range.range_for_length(100), None)

def test_range_str_end_none():
    range = Range(((0, 100),))
    # Manually set test values
    range.ranges = ((0, None),)
    assert_equal(range.__str__(), "bytes=0-")

def test_not_satisfiable():
    range = Range.parse("bytes=-100")
    assert range.range_for_length(50) is None
    range = Range.parse("bytes=100-")
    assert range.range_for_length(50) is None