diff --git a/cve_bin_tool/data_sources/osv_source.py b/cve_bin_tool/data_sources/osv_source.py
index 1266db1358..25342ef252 100644
--- a/cve_bin_tool/data_sources/osv_source.py
+++ b/cve_bin_tool/data_sources/osv_source.py
@@ -387,3 +387,8 @@ async def get_cve_data(self):
         await self.update_cve_entries()
 
         return self.format_data(self.all_cve_entries), self.source_name
+import pytest
+from unittest.mock import AsyncMock, patch
+
+from cve_bin_tool.data_sources.osv_source import OSV_Source
+
diff --git a/test/test_osv_source.py b/test/test_osv_source.py
new file mode 100644
index 0000000000..d8d40885be
--- /dev/null
+++ b/test/test_osv_source.py
@@ -0,0 +1,36 @@
+import pytest
+from unittest.mock import patch
+from cve_bin_tool.data_sources.osv_source import OSV_Source
+
+@pytest.mark.asyncio
+async def test_update_ecosystems_mocked():
+    # Create an instance of OSV_Source
+    osv = OSV_Source()
+
+    with patch("cve_bin_tool.data_sources.osv_source.aio_run_command") as mock_run:
+        # Mock gsutil ls and gsutil ls for all.zip
+        mock_run.side_effect = [
+            (b"gs://osv-vulnerabilities/ecosystem1/\n", b"", b""),   # gsutil ls base
+            (b"gs://osv-vulnerabilities/ecosystem1/all.zip\n", b"", b""),  # gsutil ls all.zip
+            (b"", b"", b"")  # fallback mock result
+        ]
+
+        await osv.update_ecosystems()
+
+        assert osv.ecosystems == ["ecosystem1"]
+
+@pytest.mark.asyncio
+@patch("cve_bin_tool.data_sources.osv_source.aio_run_command", new_callable=AsyncMock)
+async def test_update_ecosystems(mock_aio_run_command):
+    # Mock gsutil output: two folders, one of them contains all.zip
+    mock_aio_run_command.side_effect = [
+        b"https://osv-vulnerabilities/python/\nhttps://osv-vulnerabilities/rust/\n",
+        b"https://osv-vulnerabilities/python/all.zip\n",
+        b"",  # rust does not contain all.zip
+    ]
+
+    osv = OSV_Source()
+    await osv.update_ecosystems()
+
+    assert "python" in osv.ecosystems
+    assert "rust" not in osv.ecosystems