fix packaging and imports and introduce tests with pytest.

still issues with celery worker.

tests/test_app.py

@@ -0,0 +1,28 @@
+from application.app import get_vectorstore
+import os
+
+
+# Test cases for get_vectorstore function
+def test_no_active_docs():
+    data = {}
+    assert get_vectorstore(data) == os.path.join("application", "")
+
+
+def test_local_default_active_docs():
+    data = {"active_docs": "local/default"}
+    assert get_vectorstore(data) == os.path.join("application", "")
+
+
+def test_local_non_default_active_docs():
+    data = {"active_docs": "local/something"}
+    assert get_vectorstore(data) == os.path.join("application", "indexes/local/something")
+
+
+def test_default_active_docs():
+    data = {"active_docs": "default"}
+    assert get_vectorstore(data) == os.path.join("application", "")
+
+
+def test_complex_active_docs():
+    data = {"active_docs": "local/other/path"}
+    assert get_vectorstore(data) == os.path.join("application", "indexes/local/other/path")