diff --git a/trace_analysis/tests/test_core.py b/trace_analysis/tests/test_core.py
new file mode 100644
index 0000000..6d2c011
--- /dev/null
+++ b/trace_analysis/tests/test_core.py
@@ -0,0 +1,57 @@
+import json
+import os
+import tempfile
+import pytest
+from pathlib import Path
+
+from trace_analysis import core
+
+def create_test_event_file(tmp_path):
+    events = [
+        {"timestamp": "2024-07-01T12:00:00", "migration_type": "unpinned", "latency": 12},
+        {"timestamp": "2024-07-01T12:00:01", "migration_type": "unpinned", "latency": 35},
+        {"timestamp": "2024-07-01T12:00:02", "migration_type": "half_pinned", "latency": 15},
+        {"timestamp": "2024-07-01T12:00:03", "migration_type": "half_pinned", "latency": 40},
+        {"timestamp": "2024-07-01T12:00:04", "migration_type": "fully_pinned", "latency": 50}
+    ]
+    file_path = tmp_path / "test_events.json"
+    with open(file_path, "w", encoding="utf-8") as f:
+        json.dump(events, f)
+    return file_path
+
+
+def test_analyze_spikes_output_structure(tmp_path):
+    test_file = create_test_event_file(tmp_path)
+    report = core.analyze_spikes(str(test_file))
+
+    # basic type checks
+    assert isinstance(report, dict)
+    assert set(report.keys()) == {"migration_type", "timestamp", "spike_count"}
+
+    # field type checks
+    assert isinstance(report["migration_type"], str)
+    assert isinstance(report["timestamp"], str)
+    assert isinstance(report["spike_count"], int)
+
+
+def test_analyze_spikes_with_invalid_file(tmp_path):
+    bad_file = tmp_path / "missing.json"
+    with pytest.raises((FileNotFoundError, ValueError)):
+        core.analyze_spikes(str(bad_file))
+
+
+def test_analyze_spikes_counts_spikes_correctly(tmp_path):
+    events = [
+        {"timestamp": "2024-07-01T00:00:00", "migration_type": "unpinned", "latency": 10},
+        {"timestamp": "2024-07-01T00:00:01", "migration_type": "unpinned", "latency": 45},
+        {"timestamp": "2024-07-01T00:00:02", "migration_type": "unpinned", "latency": 60}
+    ]
+    fpath = tmp_path / "events.json"
+    with open(fpath, "w", encoding="utf-8") as fh:
+        json.dump(events, fh)
+
+    report = core.analyze_spikes(str(fpath))
+    # Spike detection likely based on latency > threshold, expect count >= 1
+    assert report["spike_count"] >= 1
+    assert report["migration_type"] == "unpinned"
+    assert "T" in report["timestamp"]
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