Add data_logging/tests/test_main.py

data_logging/tests/test_main.py

@@ -0,0 +1,84 @@
+import json
+import tempfile
+import os
+from datetime import datetime
+import pytest
+
+import src.data_logging.main as main
+
+
+@pytest.fixture
+def sample_logentry_dict():
+    return {
+        "timestamp": datetime.utcnow().isoformat(),
+        "temperature": 18.2,
+        "wind_speed": 1.5,
+        "error_rate": 0.03,
+    }
+
+
+def test_logentry_to_json_structure(sample_logentry_dict):
+    entry = main.LogEntry(
+        timestamp=sample_logentry_dict["timestamp"],
+        temperature=sample_logentry_dict["temperature"],
+        wind_speed=sample_logentry_dict["wind_speed"],
+        error_rate=sample_logentry_dict["error_rate"],
+    )
+    result = entry.to_json()
+
+    assert isinstance(result, dict)
+    assert set(result.keys()) == {"timestamp", "temperature", "wind_speed", "error_rate"}
+    assert isinstance(result["temperature"], float)
+    assert isinstance(result["wind_speed"], float)
+    assert isinstance(result["error_rate"], float)
+
+
+def test_log_data_creates_valid_json_line(sample_logentry_dict):
+    with tempfile.TemporaryDirectory() as tmpdir:
+        log_path = os.path.join(tmpdir, "night_telemetry.json")
+
+        # first log
+        success = main.log_data(sample_logentry_dict)
+        assert isinstance(success, bool)
+
+        # simulate re-logging to test append mode
+        another = sample_logentry_dict.copy()
+        another["temperature"] = 19.4
+        success = main.log_data(another)
+        assert success
+
+
+def test_log_data_file_output_integrity(sample_logentry_dict):
+    with tempfile.TemporaryDirectory() as tmpdir:
+        outfile = os.path.join(tmpdir, "out.json")
+
+        # monkeypatch output path by changing current working directory to tmpdir
+        cwd = os.getcwd()
+        os.chdir(tmpdir)
+        try:
+            res = main.log_data(sample_logentry_dict)
+            assert res is True
+            # ensure file created
+            expected_file = 'output/logs/night_telemetry.json'
+            subdirs = os.path.dirname(expected_file)
+            created_file = os.path.join(tmpdir, expected_file)
+            assert os.path.exists(created_file)
+            # check JSON validity
+            with open(created_file, 'r', encoding='utf-8') as f:
+                line = f.readline().strip()
+                obj = json.loads(line)
+                assert set(obj.keys()) == {"timestamp", "temperature", "wind_speed", "error_rate"}
+        finally:
+            os.chdir(cwd)
+
+
+def test_error_on_invalid_data_type():
+    invalid_data = {
+        "timestamp": "invalid_iso",
+        "temperature": "warm",
+        "wind_speed": None,
+        "error_rate": "NaN",
+    }
+    # should not raise but return False or handle internally
+    result = main.log_data(invalid_data)
+    assert result in {True, False}