diff --git a/app/backend/tests/api/test_chatbot.py b/app/backend/tests/api/test_chatbot.py
new file mode 100644
index 0000000..0fd95ac
--- /dev/null
+++ b/app/backend/tests/api/test_chatbot.py
@@ -0,0 +1,51 @@
+import pytest
+from fastapi.testclient import TestClient
+from unittest.mock import patch, MagicMock
+from fastapi import WebSocket
+import sys
+import types
+
+# Patch langchain and other heavy dependencies for import
+sys.modules['langchain_deepseek'] = MagicMock()
+sys.modules['langchain_huggingface'] = MagicMock()
+sys.modules['langchain_community.vectorstores.chroma'] = MagicMock()
+sys.modules['langchain_community.tools.tavily_search'] = MagicMock()
+sys.modules['langchain_core.prompts'] = MagicMock()
+sys.modules['langchain_core.output_parsers'] = MagicMock()
+sys.modules['langchain.prompts'] = MagicMock()
+sys.modules['langchain.schema'] = MagicMock()
+sys.modules['langgraph.graph'] = MagicMock()
+
+from api import chatbot
+
+@pytest.fixture
+def client():
+    from fastapi import FastAPI
+    app = FastAPI()
+    app.include_router(chatbot.router)
+    return TestClient(app)
+
+def test_router_exists():
+    assert hasattr(chatbot, 'router')
+
+def test_env_vars_loaded(monkeypatch):
+    monkeypatch.setenv('DEEPSEEK_API_KEY', 'dummy')
+    monkeypatch.setenv('TAVILY_API_KEY', 'dummy')
+    # Re-import to trigger env loading
+    import importlib
+    importlib.reload(chatbot)
+    assert True
+
+def test_websocket_endpoint_accepts(monkeypatch):
+    # Patch ConnectionManager
+    mock_manager = MagicMock()
+    monkeypatch.setattr(chatbot, 'manager', mock_manager)
+    ws = MagicMock(spec=WebSocket)
+    ws.receive_text = MagicMock(side_effect=[pytest.raises(StopIteration)])
+    ws.accept = MagicMock()
+    # Should not raise
+    try:
+        coro = chatbot.websocket_endpoint(ws)
+        assert hasattr(coro, '__await__')
+    except Exception as e:
+        pytest.fail(f"websocket_endpoint raised: {e}")
diff --git a/app/backend/tests/models/adaptive_rag/test_grading.py b/app/backend/tests/models/adaptive_rag/test_grading.py
new file mode 100644
index 0000000..ea1180b
--- /dev/null
+++ b/app/backend/tests/models/adaptive_rag/test_grading.py
@@ -0,0 +1,14 @@
+import pytest
+from models.adaptive_rag import grading
+
+def test_grade_documents_class():
+    doc = grading.GradeDocuments(binary_score='yes')
+    assert doc.binary_score == 'yes'
+
+def test_grade_hallucinations_class():
+    doc = grading.GradeHallucinations(binary_score='no')
+    assert doc.binary_score == 'no'
+
+def test_grade_answer_class():
+    doc = grading.GradeAnswer(binary_score='yes')
+    assert doc.binary_score == 'yes'
diff --git a/app/backend/tests/models/adaptive_rag/test_prompts_library.py b/app/backend/tests/models/adaptive_rag/test_prompts_library.py
new file mode 100644
index 0000000..f04be17
--- /dev/null
+++ b/app/backend/tests/models/adaptive_rag/test_prompts_library.py
@@ -0,0 +1,10 @@
+import pytest
+from models.adaptive_rag import prompts_library
+
+def test_prompts_are_strings():
+    assert isinstance(prompts_library.system_router, str)
+    assert isinstance(prompts_library.system_retriever_grader, str)
+    assert isinstance(prompts_library.system_hallucination_grader, str)
+    assert isinstance(prompts_library.system_answer_grader, str)
+    assert isinstance(prompts_library.system_question_rewriter, str)
+    assert isinstance(prompts_library.qa_prompt_template, str)
diff --git a/app/backend/tests/models/adaptive_rag/test_query.py b/app/backend/tests/models/adaptive_rag/test_query.py
new file mode 100644
index 0000000..24af5f8
--- /dev/null
+++ b/app/backend/tests/models/adaptive_rag/test_query.py
@@ -0,0 +1,8 @@
+import pytest
+from models.adaptive_rag import query
+
+def test_query_request_and_response():
+    req = query.QueryRequest(query="What is AI?")
+    assert req.query == "What is AI?"
+    resp = query.QueryResponse(response="Artificial Intelligence")
+    assert resp.response == "Artificial Intelligence"
diff --git a/app/backend/tests/models/adaptive_rag/test_routing.py b/app/backend/tests/models/adaptive_rag/test_routing.py
new file mode 100644
index 0000000..f6eae0b
--- /dev/null
+++ b/app/backend/tests/models/adaptive_rag/test_routing.py
@@ -0,0 +1,6 @@
+import pytest
+from models.adaptive_rag import routing
+
+def test_route_query_class():
+    route = routing.RouteQuery(datasource="vectorstore")
+    assert route.datasource == "vectorstore"
diff --git a/app/backend/tests/test_config_and_main.py b/app/backend/tests/test_config_and_main.py
new file mode 100644
index 0000000..b95c3a7
--- /dev/null
+++ b/app/backend/tests/test_config_and_main.py
@@ -0,0 +1,10 @@
+import pytest
+from importlib import import_module
+
+def test_config_import():
+    mod = import_module('config')
+    assert mod is not None
+
+def test_main_import():
+    mod = import_module('main')
+    assert mod is not None
diff --git a/app/backend/tests/utils/test_initialize_sentence_transformer.py b/app/backend/tests/utils/test_initialize_sentence_transformer.py
new file mode 100644
index 0000000..976fa30
--- /dev/null
+++ b/app/backend/tests/utils/test_initialize_sentence_transformer.py
@@ -0,0 +1,6 @@
+import pytest
+from importlib import import_module
+
+def test_initialize_sentence_transformer_import():
+    mod = import_module('utils.initialize_sentence_transformer')
+    assert mod is not None