ACME modules refactor (#187)

* Move acme.py to acme/__init__.py to prepare splitup.

* Began moving generic code out.

* Creating backends.

* Update unit tests.

* Move remaining new code out.

* Use new interface.

* Rewrite module init code.

* Add changelog.

* Add BackendException for crypto backend errors.

* Improve / uniformize ACME error reporting.

* Create ACMELegacyAccount for backwards compatibility.

* Split up ACMEAccount into ACMEClient and ACMEAccount.

* Move get_keyauthorization into module_utils.acme.challenges.

* Improve error handling.

* Move challenge and authorization handling code into module_utils.

* Add split_identifier helper.

* Move order code into module_utils.

* Move ACME v2 certificate handling code to module_utils.

* Fix/move ACME v1 certificate retrieval to module_utils as well.

* Refactor alternate chain handling code by splitting it up into simpler functions.

* Make chain matcher creation part of backend.

tests/unit/plugins/module_utils/acme/test_backend_cryptography.py

@@ -0,0 +1,64 @@
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+
+import pytest
+
+from mock import MagicMock
+
+
+from ansible_collections.community.crypto.plugins.module_utils.acme.backend_cryptography import (
+    HAS_CURRENT_CRYPTOGRAPHY,
+    CryptographyBackend,
+)
+
+from .backend_data import (
+    TEST_KEYS,
+    TEST_CSRS,
+    TEST_CERT,
+    TEST_CERT_DAYS,
+)
+
+
+if not HAS_CURRENT_CRYPTOGRAPHY:
+    pytest.skip('cryptography not found')
+
+
+@pytest.mark.parametrize("pem, result, dummy", TEST_KEYS)
+def test_eckeyparse_cryptography(pem, result, dummy, tmpdir):
+    fn = tmpdir / 'test.pem'
+    fn.write(pem)
+    module = MagicMock()
+    backend = CryptographyBackend(module)
+    error, key = backend.parse_key(key_file=str(fn))
+    assert error is None
+    key.pop('key_obj')
+    assert key == result
+    error, key = backend.parse_key(key_content=pem)
+    assert error is None
+    key.pop('key_obj')
+    assert key == result
+
+
+@pytest.mark.parametrize("csr, result, openssl_output", TEST_CSRS)
+def test_csridentifiers_cryptography(csr, result, openssl_output, tmpdir):
+    fn = tmpdir / 'test.csr'
+    fn.write(csr)
+    module = MagicMock()
+    backend = CryptographyBackend(module)
+    identifiers = backend.get_csr_identifiers(csr_filename=str(fn))
+    assert identifiers == result
+    identifiers = backend.get_csr_identifiers(csr_content=csr)
+    assert identifiers == result
+
+
+@pytest.mark.parametrize("now, expected_days", TEST_CERT_DAYS)
+def test_certdays_cryptography(now, expected_days, tmpdir):
+    fn = tmpdir / 'test-cert.pem'
+    fn.write(TEST_CERT)
+    module = MagicMock()
+    backend = CryptographyBackend(module)
+    days = backend.get_cert_days(cert_filename=str(fn), now=now)
+    assert days == expected_days
+    days = backend.get_cert_days(cert_content=TEST_CERT, now=now)
+    assert days == expected_days