diff --git a/opendata_module/opmon_opendata/api/helpers.py b/opendata_module/opmon_opendata/api/helpers.py
index dfff756..cccdeff 100644
--- a/opendata_module/opmon_opendata/api/helpers.py
+++ b/opendata_module/opmon_opendata/api/helpers.py
@@ -60,13 +60,15 @@ def generate_ndjson_stream(postgres: PostgreSQL_LogManager, date: datetime,
     with GzipFile(fileobj=gzip_buffer, mode='wb') as gzip_file:
         count = 0
         buffer_size = settings['opendata'].get('stream-buffer-lines', DEFAULT_STREAM_BUFFER_LINES)
-        for row in data_cursor:
+        gzip_file.write(b'[\n')
+        for idx, row in enumerate(data_cursor):
+            if idx > 0:
+                gzip_file.write(b',\n')
             json_obj = {column_name: row[column_idx] for column_idx, column_name in enumerate(column_names)}
             # Must manually convert Postgres dates to string to be compatible with JSON format
             for date_column in date_columns:
                 json_obj[date_column] = datetime.strftime(json_obj[date_column], '%Y-%m-%d')
             gzip_file.write(bytes(json.dumps(json_obj), 'utf-8'))
-            gzip_file.write(b'\n')
             count += 1
             if count == buffer_size:
                 count = 0
@@ -78,6 +80,8 @@ def generate_ndjson_stream(postgres: PostgreSQL_LogManager, date: datetime,
                     # Empty buffer to free memory
                     gzip_buffer.truncate(0)
                     gzip_buffer.seek(0)
+        gzip_file.write(b'\n]')
+
     # Final data gets written when GzipFile is closed
     yield gzip_buffer.getvalue()
 
diff --git a/opendata_module/opmon_opendata/tests/test_helpers.py b/opendata_module/opmon_opendata/tests/test_helpers.py
new file mode 100644
index 0000000..79b885c
--- /dev/null
+++ b/opendata_module/opmon_opendata/tests/test_helpers.py
@@ -0,0 +1,72 @@
+#
+# The MIT License 
+# Copyright (c) 2021- Nordic Institute for Interoperability Solutions (NIIS)
+# Copyright (c) 2017-2020 Estonian Information System Authority (RIA)
+#  
+# Permission is hereby granted, free of charge, to any person obtaining a copy 
+# of this software and associated documentation files (the "Software"), to deal 
+# in the Software without restriction, including without limitation the rights 
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
+# copies of the Software, and to permit persons to whom the Software is 
+# furnished to do so, subject to the following conditions: 
+#  
+# The above copyright notice and this permission notice shall be included in 
+# all copies or substantial portions of the Software. 
+#  
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
+# THE SOFTWARE.
+#
+import gzip
+import json
+import io
+import pytest
+
+from datetime import date, datetime
+from opmon_opendata.api import helpers
+
+
+SETTINGS = {
+    'opendata': {}
+}
+
+
+@pytest.fixture
+def postgres(mocker):
+    return mocker.Mock()
+
+
+@pytest.mark.parametrize(
+    "column_types, data_cursor, expected_output",
+    [
+        # Test case: Multiple results
+        (
+            [('foo', 'integer'), ('bar', 'character varying'), ('baz', 'date')],
+            [('1', 'aaa', date(2025, 1, 1)), ('2', 'bbb', date(2025, 2, 2))],
+            [{'foo': '1', 'bar': 'aaa', 'baz': '2025-01-01'},
+             {'foo': '2', 'bar': 'bbb', 'baz': '2025-02-02'}]
+        ),
+        # Test case: No results
+        (
+            [('foo', 'integer')],
+            [],
+            []
+        )
+    ]
+)
+def test_generate_ndjson_stream_creates_correct_json(postgres, column_types, data_cursor, expected_output):
+    postgres.get_column_names_and_types.return_value = column_types
+    postgres.get_data_cursor.return_value = data_cursor
+    gzipped_file_stream = helpers.generate_ndjson_stream(postgres, datetime.now(), [], [], [], SETTINGS)
+    decompressed_data = decompress_gzip(gzipped_file_stream)
+    assert json.loads(decompressed_data) == expected_output
+
+def decompress_gzip(gzipped_file_stream):
+    compressed_data = b"".join(gzipped_file_stream)
+    with gzip.GzipFile(fileobj=io.BytesIO(compressed_data), mode="rb") as f:
+        decompressed_data = f.read().decode()
+        return decompressed_data