Make all module_utils and plugin_utils private (#887)

* Add leading underscore. Remove deprecated module utils.

* Document module and plugin utils as private. Add changelog fragment.

* Convert relative to absolute imports.

* Remove unnecessary imports.

tests/unit/plugins/module_utils/_openssh/test_utils.py

@@ -0,0 +1,147 @@
+# Copyright (c) Ansible Project
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from __future__ import annotations
+
+import typing as t
+
+import pytest
+from ansible_collections.community.crypto.plugins.module_utils._openssh.utils import (
+    OpensshParser,
+    _OpensshWriter,
+    parse_openssh_version,
+)
+
+
+SSH_VERSION_STRING = "OpenSSH_7.9p1, OpenSSL 1.1.0i-fips  14 Aug 2018"
+SSH_VERSION_NUMBER = "7.9"
+
+VALID_BOOLEAN: list[bool] = [True, False]
+INVALID_BOOLEAN: list[t.Any] = [0x02]
+VALID_UINT32: list[int] = [
+    0x00,
+    0x01,
+    0x01234567,
+    0xFFFFFFFF,
+]
+INVALID_UINT32: list[int] = [
+    0xFFFFFFFFF,
+    -1,
+]
+VALID_UINT64: list[int] = [
+    0x00,
+    0x01,
+    0x0123456789ABCDEF,
+    0xFFFFFFFFFFFFFFFF,
+]
+INVALID_UINT64: list[int] = [
+    0xFFFFFFFFFFFFFFFFF,
+    -1,
+]
+VALID_STRING: list[bytes] = [
+    b"test string",
+]
+INVALID_STRING: list[t.Any] = [
+    [],
+]
+# See https://datatracker.ietf.org/doc/html/rfc4251#section-5 for examples source
+VALID_MPINT: list[int] = [
+    0x00,
+    0x9A378F9B2E332A7,
+    0x80,
+    -0x1234,
+    -0xDEADBEEF,
+    # Additional large int test
+    0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF,
+]
+INVALID_MPINT: list[t.Any] = [
+    [],
+]
+
+
+def test_parse_openssh_version() -> None:
+    assert parse_openssh_version(SSH_VERSION_STRING) == SSH_VERSION_NUMBER
+
+
+@pytest.mark.parametrize("boolean", VALID_BOOLEAN)
+def test_valid_boolean(boolean: bool) -> None:
+    assert OpensshParser(_OpensshWriter().boolean(boolean).bytes()).boolean() == boolean
+
+
+@pytest.mark.parametrize("boolean", INVALID_BOOLEAN)
+def test_invalid_boolean(boolean: t.Any) -> None:
+    with pytest.raises(TypeError):
+        _OpensshWriter().boolean(boolean)
+
+
+@pytest.mark.parametrize("uint32", VALID_UINT32)
+def test_valid_uint32(uint32: int) -> None:
+    assert OpensshParser(_OpensshWriter().uint32(uint32).bytes()).uint32() == uint32
+
+
+@pytest.mark.parametrize("uint32", INVALID_UINT32)
+def test_invalid_uint32(uint32: int) -> None:
+    with pytest.raises(ValueError):
+        _OpensshWriter().uint32(uint32)
+
+
+@pytest.mark.parametrize("uint64", VALID_UINT64)
+def test_valid_uint64(uint64: int) -> None:
+    assert OpensshParser(_OpensshWriter().uint64(uint64).bytes()).uint64() == uint64
+
+
+@pytest.mark.parametrize("uint64", INVALID_UINT64)
+def test_invalid_uint64(uint64: int) -> None:
+    with pytest.raises(ValueError):
+        _OpensshWriter().uint64(uint64)
+
+
+@pytest.mark.parametrize("ssh_string", VALID_STRING)
+def test_valid_string(ssh_string: bytes) -> None:
+    assert (
+        OpensshParser(_OpensshWriter().string(ssh_string).bytes()).string()
+        == ssh_string
+    )
+
+
+@pytest.mark.parametrize("ssh_string", INVALID_STRING)
+def test_invalid_string(ssh_string: t.Any) -> None:
+    with pytest.raises(TypeError):
+        _OpensshWriter().string(ssh_string)
+
+
+@pytest.mark.parametrize("mpint", VALID_MPINT)
+def test_valid_mpint(mpint: int) -> None:
+    assert OpensshParser(_OpensshWriter().mpint(mpint).bytes()).mpint() == mpint
+
+
+@pytest.mark.parametrize("mpint", INVALID_MPINT)
+def test_invalid_mpint(mpint: t.Any) -> None:
+    with pytest.raises(TypeError):
+        _OpensshWriter().mpint(mpint)
+
+
+def test_valid_seek() -> None:
+    buffer = bytearray(b"buffer")
+    parser = OpensshParser(buffer)
+    parser.seek(len(buffer))
+    assert parser.remaining_bytes() == 0
+    parser.seek(-len(buffer))
+    assert parser.remaining_bytes() == len(buffer)
+
+
+def test_invalid_seek() -> None:
+    buffer = b"buffer"
+    parser = OpensshParser(buffer)
+
+    with pytest.raises(ValueError):
+        parser.seek(len(buffer) + 1)
+
+    with pytest.raises(ValueError):
+        parser.seek(-1)
+
+
+def test_writer_bytes() -> None:
+    buffer = bytearray(b"buffer")
+    assert _OpensshWriter(buffer).bytes() == buffer