diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/unit/__init__.py b/tests/unit/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/unit/test_parameter.py b/tests/unit/test_parameter.py
new file mode 100644
index 0000000..862344d
--- /dev/null
+++ b/tests/unit/test_parameter.py
@@ -0,0 +1,46 @@
+from models.scenario import Scenario
+from main import app
+from config.database import Base, engine
+from fastapi.testclient import TestClient
+import pytest
+import os
+import sys
+sys.path.append(os.path.dirname(os.path.dirname(os.path.dirname(__file__))))
+
+# Setup and teardown
+
+
+def setup_module(module):
+    Base.metadata.create_all(bind=engine)
+
+
+def teardown_module(module):
+    Base.metadata.drop_all(bind=engine)
+
+
+client = TestClient(app)
+
+# Helper to create a scenario
+
+
+def create_test_scenario():
+    resp = client.post("/api/scenarios/",
+                       json={"name": "ParamTest", "description": "Desc"})
+    assert resp.status_code == 200
+    return resp.json()["id"]
+
+
+def test_create_and_list_parameter():
+    # Ensure scenario exists
+    scen_id = create_test_scenario()
+    # Create a parameter
+    resp = client.post(
+        "/api/parameters/", json={"scenario_id": scen_id, "name": "param1", "value": 3.14})
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["name"] == "param1"
+    # List parameters
+    resp2 = client.get("/api/parameters/")
+    assert resp2.status_code == 200
+    data2 = resp2.json()
+    assert any(p["name"] == "param1" for p in data2)
diff --git a/tests/unit/test_reporting.py b/tests/unit/test_reporting.py
new file mode 100644
index 0000000..bb858a1
--- /dev/null
+++ b/tests/unit/test_reporting.py
@@ -0,0 +1,27 @@
+from services.reporting import generate_report
+from routes.reporting import router
+from fastapi.testclient import TestClient
+from main import app
+import pytest
+
+# Function test
+def test_generate_report_empty():
+    report = generate_report([])
+    assert isinstance(report, dict)
+
+# Endpoint test
+def test_reporting_endpoint_invalid_input():
+    client = TestClient(app)
+    resp = client.post("/api/reporting/summary", json={})
+    assert resp.status_code == 400
+    assert resp.json()["detail"] == "Invalid input format"
+
+
+def test_reporting_endpoint_success():
+    client = TestClient(app)
+    # Minimal input: list of dicts
+    input_data = [{"iteration": 1, "result": 10.0}]
+    resp = client.post("/api/reporting/summary", json=input_data)
+    assert resp.status_code == 200
+    data = resp.json()
+    assert isinstance(data, dict)
diff --git a/tests/unit/test_scenario.py b/tests/unit/test_scenario.py
new file mode 100644
index 0000000..b4ed93f
--- /dev/null
+++ b/tests/unit/test_scenario.py
@@ -0,0 +1,36 @@
+# ensure project root is on sys.path for module imports
+from main import app
+from routes.scenarios import router
+from config.database import Base, engine
+from fastapi.testclient import TestClient
+import pytest
+import os
+import sys
+sys.path.append(os.path.dirname(os.path.dirname(os.path.dirname(__file__))))
+
+# Create tables for testing
+
+
+def setup_module(module):
+    Base.metadata.create_all(bind=engine)
+
+
+def teardown_module(module):
+    Base.metadata.drop_all(bind=engine)
+
+
+client = TestClient(app)
+
+
+def test_create_and_list_scenario():
+    # Create a scenario
+    response = client.post(
+        "/api/scenarios/", json={"name": "Test", "description": "Desc"})
+    assert response.status_code == 200
+    data = response.json()
+    assert data["name"] == "Test"
+    # List scenarios
+    response2 = client.get("/api/scenarios/")
+    assert response2.status_code == 200
+    data2 = response2.json()
+    assert any(s["name"] == "Test" for s in data2)
diff --git a/tests/unit/test_simulation.py b/tests/unit/test_simulation.py
new file mode 100644
index 0000000..2899e20
--- /dev/null
+++ b/tests/unit/test_simulation.py
@@ -0,0 +1,42 @@
+from services.simulation import run_simulation
+from main import app
+from config.database import Base, engine
+from fastapi.testclient import TestClient
+import pytest
+
+# Setup and teardown
+
+
+def setup_module(module):
+    Base.metadata.create_all(bind=engine)
+
+
+def teardown_module(module):
+    Base.metadata.drop_all(bind=engine)
+
+
+client = TestClient(app)
+
+# Direct function test
+
+
+def test_run_simulation_function_returns_list():
+    results = run_simulation([], iterations=10)
+    assert isinstance(results, list)
+    assert results == []
+
+# Endpoint tests
+
+
+def test_simulation_endpoint_no_params():
+    resp = client.post("/api/simulations/run", json=[])
+    assert resp.status_code == 400
+    assert resp.json()["detail"] == "No parameters provided"
+
+
+def test_simulation_endpoint_success():
+    params = [{"name": "param1", "value": 2.5}]
+    resp = client.post("/api/simulations/run", json=params)
+    assert resp.status_code == 200
+    data = resp.json()
+    assert isinstance(data, list)