def test_n_neg():
"""Perform unit tests on test-driven_dev.n_neg."""
assert test_driven_dev.n_neg('E') == 1
assert test_driven_dev.n_neg('D') == 1
assert test_driven_dev.n_neg('') == 0
assert test_driven_dev.n_neg('ACKLWTTAE') == 1
assert test_driven_dev.n_neg('DDDDEEEE') == 8
assert test_driven_dev.n_neg('acklwttae') == 1
def test_n_neg_for_invalid_amino_acid():
with pytest.raises(RuntimeError) as excinfo:
test_driven_dev.n_neg('Z')
excinfo.match("Z is not a valid amino acid")
def test_n_neg_for_lower_case_sequences():
assert test_driven_dev.n_neg('acklwttae') == 1
def test_n_neg_for_longer_sequences():
assert test_driven_dev.n_neg('ACKLWTTAE') == 1
assert test_driven_dev.n_neg('DDDDEEEE') == 8
def test_n_neg_for_empty_sequence():
assert test_driven_dev.n_neg('') == 0
def test_n_neg_for_single_E_or_D():
"""Perform unit tests on n_neg."""
assert test_driven_dev.n_neg('E') == 1
assert test_driven_dev.n_neg('D') == 1