diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5ceb386
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+venv
diff --git a/Copy_of_Untitled7.ipynb b/Copy_of_Untitled7.ipynb
index ba82ae8..03f4ebd 100644
--- a/Copy_of_Untitled7.ipynb
+++ b/Copy_of_Untitled7.ipynb
@@ -222,6 +222,39 @@
           "metadata": {}
         }
       ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {},
+      "outputs": [],
+      "source": [
+        "# --- UNIT TESTS ---\n",
+        "import numpy as np\n",
+        "\n",
+        "def test_coherence_index():\n",
+        "    # Test with r=0, should be 1.0\n",
+        "    assert np.isclose(coherence_index(0, 1.5), 1.0), \"Failed on r=0\"\n",
+        "    \n",
+        "    # Test with typical values\n",
+        "    r = 10\n",
+        "    rho_info = 1.0\n",
+        "    expected = np.exp(-10 / (10 * 1.0))\n",
+        "    assert np.isclose(coherence_index(r, rho_info), expected), \"Failed on typical values\"\n",
+        "    \n",
+        "    # Test with array input\n",
+        "    r_arr = np.array([0, 10, 20])\n",
+        "    expected_arr = np.exp(-r_arr / (10 * 1.0))\n",
+        "    np.testing.assert_allclose(coherence_index(r_arr, 1.0), expected_arr, err_msg=\"Failed on array input\")\n",
+        "    \n",
+        "    # Test error condition (e.g. division by zero if rho_info is 0)\n",
+        "    # Although the function doesn't explicitly handle it, it will return inf or raise warning. \n",
+        "    # We focus on the functional math values.\n",
+        "    print(\"All tests for coherence_index passed!\")\n",
+        "\n",
+        "if __name__ == \"__main__\":\n",
+        "    test_coherence_index()\n"
+      ]
     }
   ]
 }
\ No newline at end of file