tests: Add utility to compare sequences

This is useful if you want to check if some function was called with a
sequence, without caring about the concrete underlying type, so the
implementation can change and tests don't need to be updated as long
as the interface stays the same.

For example: mock.assert_called_once_with(a_sequence(1, 2, 3))

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

tests/utils/__init__.py

@@ -2,3 +2,9 @@
 # Copyright © 2022 Frequenz Energy-as-a-Service GmbH
 
 """Utilities for testing purposes."""
+
+from ._a_sequence import a_sequence
+
+__all__ = [
+    "a_sequence",
+]

tests/utils/_a_sequence.py

@@ -0,0 +1,44 @@
+# tests/timeseries/test_resampling.py:93: License: MIT
+# Copyright © 2022 Frequenz Energy-as-a-Service GmbH
+
+"""Helper class to compare two sequences without caring about the underlying type."""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+from typing import Any
+
+
+# Disabling the lint because it reads easier in tests like this
+class a_sequence:  # pylint: disable=invalid-name
+    """Helper class to compare two sequences without caring about the underlying type.
+
+    Examples:
+        >>> from collections import deque
+        >>> (1, 2) == a_sequence(1, 2)
+        >>> True
+        >>> deque([1, 2]) == a_sequence(1, 2)
+        >>> True
+        >>> deque([2, 1]) == a_sequence(1, 2)
+        >>> False
+        >>> 1 == a_sequence(1, 2)
+        >>> False
+    """
+
+    def __init__(self, *sequence: Any) -> None:
+        """Create an instance."""
+        self.sequence: Sequence[Any] = sequence
+
+    def __eq__(self, other: Any) -> bool:
+        """# noqa D105 (Missing docstring in magic method)."""
+        if not isinstance(other, Sequence):
+            return False
+        return list(self.sequence) == list(other)
+
+    def __str__(self) -> str:
+        """# noqa D105 (Missing docstring in magic method)."""
+        return f"{self.__class__.__name__}({', '.join(str(s) for s in self.sequence)})"
+
+    def __repr__(self) -> str:
+        """# noqa D105 (Missing docstring in magic method)."""
+        return f"{self.__class__.__name__}({', '.join(repr(s) for s in self.sequence)})"