diff --git a/dataset_exporter/tests/test_core.py b/dataset_exporter/tests/test_core.py
new file mode 100644
index 0000000..00311cd
--- /dev/null
+++ b/dataset_exporter/tests/test_core.py
@@ -0,0 +1,79 @@
+import json
+import csv
+from pathlib import Path
+import pytest
+
+import src.dataset_exporter.core as core
+
+
+@pytest.fixture
+def sample_dataset():
+    return [
+        {
+            'timestamp': '2024-01-01T00:00:00',
+            'decision': 'PASS',
+            'warn_rate': 0.05,
+            'fail_count': 2,
+            'unknown_count': 0,
+            'pinned': False,
+        },
+        {
+            'timestamp': '2024-01-02T00:00:00',
+            'decision': 'FAIL',
+            'warn_rate': 0.2,
+            'fail_count': 10,
+            'unknown_count': 1,
+            'pinned': True,
+        },
+    ]
+
+
+def test_export_jsonl(tmp_path: Path, sample_dataset):
+    output = tmp_path / 'dataset.jsonl'
+    options = core.ExportOptions(output_format='jsonl', output_path=str(output))
+    core.export_dataset(sample_dataset, options.output_format, options.output_path)
+    
+    assert output.exists(), 'JSONL file was not created.'
+
+    with open(output, 'r', encoding='utf-8') as f:
+        lines = [json.loads(line) for line in f]
+
+    assert len(lines) == len(sample_dataset)
+    assert lines[0]['decision'] == 'PASS'
+    assert all(isinstance(item, dict) for item in lines)
+
+
+def test_export_csv(tmp_path: Path, sample_dataset):
+    output = tmp_path / 'dataset.csv'
+    options = core.ExportOptions(output_format='csv', output_path=str(output))
+    core.export_dataset(sample_dataset, options.output_format, options.output_path)
+
+    assert output.exists(), 'CSV file was not created.'
+
+    with open(output, 'r', encoding='utf-8') as f:
+        reader = csv.DictReader(f)
+        rows = list(reader)
+
+    assert len(rows) == len(sample_dataset)
+    assert set(rows[0].keys()) == set(sample_dataset[0].keys())
+    assert rows[1]['decision'] == 'FAIL'
+
+
+def test_export_invalid_format(tmp_path: Path, sample_dataset):
+    output = tmp_path / 'dataset.invalid'
+    with pytest.raises(ValueError):
+        core.export_dataset(sample_dataset, 'xml', str(output))
+
+
+def test_empty_dataset_jsonl(tmp_path: Path):
+    output = tmp_path / 'empty.jsonl'
+    core.export_dataset([], 'jsonl', str(output))
+    with open(output, 'r', encoding='utf-8') as f:
+        content = f.read()
+    assert content == '', 'JSONL export of empty dataset should produce an empty file.'
+
+
+def test_invalid_dataset_type(tmp_path: Path):
+    output = tmp_path / 'invalid.jsonl'
+    with pytest.raises(TypeError):
+        core.export_dataset({'non': 'list'}, 'jsonl', str(output))
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