How to use the cutadapt.adapters.BackAdapter function in cutadapt

def test_paired_adapter_cutter_actions(action, expected_trimmed1, expected_trimmed2):
    from cutadapt.adapters import BackAdapter
    a1 = BackAdapter("GGTTAA")
    a2 = BackAdapter("AACCGG")
    s1 = Sequence("name", "CCCCGGTTAACCCC")
    s2 = Sequence("name", "TTTTAACCGGTTTT")
    pac = PairedAdapterCutter([a1], [a2], action=action)
    info1 = ModificationInfo(s1)
    info2 = ModificationInfo(s2)
    trimmed1, trimmed2 = pac(s1, s2, info1, info2)
    assert expected_trimmed1 == trimmed1.sequence
    assert expected_trimmed2 == trimmed2.sequence

def test_back_adapter_partial_occurrence_in_front():
    adapter = BackAdapter("CTGAATT", max_error_rate=0, min_overlap=4)
    assert adapter.match_to("AATTGGGGGGG") is None

def test_linked_adapter():
    front_adapter = PrefixAdapter('AAAA', min_overlap=4)
    back_adapter = BackAdapter('TTTT', min_overlap=3)

    linked_adapter = LinkedAdapter(
        front_adapter, back_adapter, front_required=True, back_required=False, name='name')
    assert linked_adapter.front_adapter.min_overlap == 4
    assert linked_adapter.back_adapter.min_overlap == 3

    read = Sequence(name='seq', sequence='AAAACCCCCTTTT')
    trimmed = linked_adapter.match_to(read.sequence).trimmed(read)
    assert trimmed.name == 'seq'
    assert trimmed.sequence == 'CCCCC'

def test_paired_adapter_cutter_actions(action, expected_trimmed1, expected_trimmed2):
    from cutadapt.adapters import BackAdapter
    a1 = BackAdapter("GGTTAA")
    a2 = BackAdapter("AACCGG")
    s1 = Sequence("name", "CCCCGGTTAACCCC")
    s2 = Sequence("name", "TTTTAACCGGTTTT")
    pac = PairedAdapterCutter([a1], [a2], action=action)
    info1 = ModificationInfo(s1)
    info2 = ModificationInfo(s2)
    trimmed1, trimmed2 = pac(s1, s2, info1, info2)
    assert expected_trimmed1 == trimmed1.sequence
    assert expected_trimmed2 == trimmed2.sequence

def test_statistics():
    read = Sequence('name', 'AAAACCCCAAAA')
    adapters = [BackAdapter("CCCC", max_error_rate=0.1)]
    cutter = AdapterCutter(adapters, times=3)
    cutter(read, ModificationInfo(read))
    # TODO make this a lot simpler
    trimmed_bp = 0
    for adapter in adapters:
        for d in (cutter.adapter_statistics[adapter].front.lengths,
                cutter.adapter_statistics[adapter].back.lengths):
            trimmed_bp += sum(seqlen * count for (seqlen, count) in d.items())
    assert trimmed_bp <= len(read), trimmed_bp

def test_issue_52():
    adapter = BackAdapter(
        sequence='GAACTCCAGTCACNNNNN',
        max_error_rate=0.12,
        min_overlap=5,
        read_wildcards=False,
        adapter_wildcards=True)
    sequence = "CCCCAGAACTACAGTCCCGGC"
    am = RemoveAfterMatch(astart=0, astop=17, rstart=5, rstop=21, matches=15, errors=2,
        adapter=adapter, sequence=sequence)
    assert am.wildcards() == 'GGC'
    """
    The result above should actually be 'CGGC' since the correct

def test_anywhere_parameter_back():
    parser = AdapterParser(max_error_rate=0.2, min_overlap=4, read_wildcards=False,
        adapter_wildcards=False, indels=True)
    adapter = list(parser.parse('CTGAAGTGAAGTACACGGTT;anywhere', 'back'))[0]
    assert isinstance(adapter, BackAdapter)
    assert adapter._force_anywhere

    # TODO move the rest to a separate test
    read = Sequence('foo1', 'TGAAGTACACGGTTAAAAAAAAAA')
    from cutadapt.modifiers import AdapterCutter
    cutter = AdapterCutter([adapter])
    trimmed_read = cutter(read, ModificationInfo(read))
    assert trimmed_read.sequence == ''

def test_adapter_cutter():
    from cutadapt.adapters import BackAdapter
    a1 = BackAdapter("GTAGTCCCGC")
    a2 = BackAdapter("GTAGTCCCCC")
    match = AdapterCutter.best_match([a1, a2], Sequence("name", "ATACCCCTGTAGTCCCC"))
    assert match.adapter is a2

def test_info_record():
    adapter = BackAdapter(
        sequence='GAACTCCAGTCACNNNNN',
        max_error_rate=0.12,
        min_overlap=5,
        read_wildcards=False,
        adapter_wildcards=True,
        name="Foo")
    read = Sequence(name="abc", sequence='CCCCAGAACTACAGTCCCGGC')
    am = RemoveAfterMatch(astart=0, astop=17, rstart=5, rstop=21, matches=15, errors=2,
        adapter=adapter, sequence=read.sequence)
    assert am.get_info_records(read) == [[
        "",
        2,
        5,
        21,
        'CCCCA',
        'GAACTACAGTCCCGGC',

def test_str():
    a = BackAdapter('ACGT', max_error_rate=0.1)
    str(a)
    str(a.match_to("TTACGT"))