1 files changed, 57 insertions, 0 deletions
diff --git a/test/test_csv_writer.py b/test/test_csv_writer.py
new file mode 100644
index 0000000..eceac28
--- /dev/null
+++ b/test/test_csv_writer.py
@@ -0,0 +1,57 @@
+import io
+import csv
+from obfuscator.csv_writer import create_byte_stream
+
+
+def csv_bytes_to_list(csv_bytes: bytes):
+    csv_string = csv_bytes.decode("utf-8")
+    f = io.StringIO(csv_string)
+    reader = csv.DictReader(f)
+    return [dict(row) for row in reader]
+
+
+def test_create_byte_stream_valid_data():
+    data = [
+        {"student_id": "1234", "name": "Student 1", "course": "Course 1"},
+        {"student_id": "5678", "name": "Student 2", "course": "Course 2"},
+    ]
+    csv_bytes = create_byte_stream(data)
+    result = csv_bytes_to_list(csv_bytes)
+    assert result == data
+
+
+def test_create_byte_stream_empty_data():
+    csv_bytes = create_byte_stream([])
+    assert csv_bytes == b""
+
+
+def test_create_byte_stream_handles_quoted_fields():
+    data = [
+        {"student_id": "1234", "name": 'Student "One"', "course": "Course, A"},
+        {"student_id": "5678", "name": 'Student "Two"', "course": "Course, B"},
+    ]
+    csv_bytes = create_byte_stream(data)
+    result = csv_bytes_to_list(csv_bytes)
+    assert result == data
+
+
+def test_create_byte_stream_consistent_header_order():
+    data = [
+        {"student_id": "1234", "name": "Alice", "course": "Math"},
+        {"student_id": "5678", "name": "Bob", "course": "Science"},
+    ]
+    csv_bytes = create_byte_stream(data)
+    csv_string = csv_bytes.decode("utf-8")
+    header_line = csv_string.splitlines()[0]
+    expected_header = ",".join(data[0].keys())
+    assert header_line == expected_header
+
+
+def test_create_byte_stream_special_characters():
+    data = [
+        {"student_id": "1234", "name": "Student 1", "course": "Line1\nLine2"},
+        {"student_id": "5678", "name": "Student 2", "course": "Value with, comma"},
+    ]
+    csv_bytes = create_byte_stream(data)
+    result = csv_bytes_to_list(csv_bytes)
+    assert result == data