from pytest import mark
products = [{'text': 'bla bla', 'fields': [('bla', 0), ('foo', -1)]}, {
    'text': 'foo bar', 'fields': [('bla', -1), ('foo', 0), ('bar', 4)]}]
possible_params = []
for product in products:
    for field_key, field_value in product['fields']:
        possible_params.append((product['text'], field_key, field_value))

@mark.parametrize('text,field_key,field_value', possible_params)
def test_parser(text, field_key, field_value):
    assert text.find(field_key) == field_value
Как параметризовать тест, взяв параметры из параметризованного прибора?