Add hotspot_logging/tests/test_core.py

hotspot_logging/tests/test_core.py

@@ -0,0 +1,66 @@
+import json
+import io
+import os
+from datetime import datetime
+import pytest
+
+import hotspot_logging.core as core
+
+@pytest.fixture
+def mock_output_file(tmp_path):
+    path = tmp_path / "hotspot_log.json"
+    yield path
+    if path.exists():
+        path.unlink()
+
+@pytest.mark.parametrize(
+    "near_expiry, total, expected",
+    [
+        (0, 10, 0.0),
+        (5, 10, 0.5),
+        (10, 10, 1.0),
+    ],
+)
+def test_log_hotspot_ratio_valid(monkeypatch, tmp_path, near_expiry, total, expected):
+    output_file = tmp_path / "hotspot_log.json"
+    records = []
+
+    def fake_print(entry):
+        records.append(entry)
+
+    monkeypatch.setattr(core, "_write_log_entry", lambda entry, _: records.append(entry))
+
+    core.log_hotspot_ratio(1.0, near_expiry, total, output_path=output_file)
+    assert len(records) == 1
+    entry = records[0]
+
+    # Validate log entry schema
+    assert isinstance(entry, dict)
+    assert set(entry.keys()) == {"timestamp", "hotspot_ratio"}
+    assert isinstance(entry["timestamp"], str)
+    assert isinstance(entry["hotspot_ratio"], float)
+    # Ratio tolerance
+    assert abs(entry["hotspot_ratio"] - expected) < 1e-9
+    # Valid ISO-8601 timestamp
+    datetime.fromisoformat(entry["timestamp"])
+
+
+def test_log_hotspot_ratio_zero_jobs(monkeypatch, tmp_path):
+    output_file = tmp_path / "hotspot_log.json"
+    records = []
+    monkeypatch.setattr(core, "_write_log_entry", lambda entry, _: records.append(entry))
+
+    with pytest.raises(ValueError):
+        core.log_hotspot_ratio(1.0, 5, 0, output_path=output_file)
+
+
+def test_json_written_to_file(tmp_path):
+    output_file = tmp_path / "hotspot_log.json"
+    core.log_hotspot_ratio(2.0, 1, 4, output_path=output_file)
+    assert output_file.exists()
+    content = json.loads(output_file.read_text())
+    assert isinstance(content, list)
+    assert len(content) == 1
+    entry = content[0]
+    assert set(entry.keys()) == {"timestamp", "hotspot_ratio"}
+    assert isinstance(entry["hotspot_ratio"], float)