add a mock progress implementation

progress_api/backends/mock.py

@@ -0,0 +1,56 @@
+# This file is part of Progress API.
+# Copyright (C) 2023 - 2024 Drexel University and contributors
+# Licensed under the MIT license, see LICENSE.md for details.
+# SPDX-License-Identifier: MIT
+
+"""
+Mock backend that records progress updates for testing.
+"""
+from __future__ import annotations
+
+from typing import Optional
+
+from .. import api
+from . import ProgressBackend, ProgressBarSpec
+
+
+class MockProgressBackend(ProgressBackend):
+    """
+    Progress bar backend that records progress updates in a list for testing.
+    """
+
+    record: list[str]
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.record = []
+
+    def create_bar(self, spec: ProgressBarSpec) -> api.Progress:
+        self.record.append(f"start {spec.label} {spec.total}")
+        return MockProgress(self, spec)
+
+
+class MockProgress(api.Progress):
+    backend: MockProgressBackend
+
+    def __init__(self, backend: MockProgressBackend, spec: ProgressBarSpec):
+        self.backend = backend
+        self.spec = spec
+
+    def set_label(self, label: Optional[str]):
+        pass
+
+    def set_total(self, total: int):
+        pass
+
+    def update(
+        self,
+        n: int = 1,
+        state: Optional[str] = None,
+        src_state: Optional[str] = None,
+        metric: int | str | float | None = None,
+    ):
+        self.backend.record.append(f"update {self.spec.label} {n} ({src_state} -> {state})")
+
+    def finish(self):
+        self.backend.record.append(f"finish {self.spec.label}")