diff --git a/sorting_searching/insertion_sort/__init__.py b/sorting_searching/insertion_sort/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/sorting_searching/insertion_sort/insertion_sort_challenge.ipynb b/sorting_searching/insertion_sort/insertion_sort_challenge.ipynb
new file mode 100644
index 0000000..8ae1754
--- /dev/null
+++ b/sorting_searching/insertion_sort/insertion_sort_challenge.ipynb
@@ -0,0 +1,145 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Implement insertion sort.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "*Problem statements are often intentionally ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
+    "\n",
+    "* Is a naiive solution sufficient?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* Empty input -> []\n",
+    "* One element -> [element]\n",
+    "* Two or more elements"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Refer to the solution notebook.  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def insertion_sort(data):\n",
+    "    # TODO: Implement me\n",
+    "    pass"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test\n",
+    "\n",
+    "*It is important to identify and run through general and edge cases from the [Test Cases](#Test-Cases) section by hand.  You generally will not be asked to write a unit test like what is shown below.*\n",
+    "\n",
+    "**The following unit test is expected to fail until you solve the challenge.**"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "# %load test_insertion_sort.py\n",
+    "from nose.tools import assert_equal\n",
+    "\n",
+    "\n",
+    "class TestInsertionSort(object):\n",
+    "    \n",
+    "    def test_insertion_sort(self):\n",
+    "        print('Empty input')\n",
+    "        data = []\n",
+    "        insertion_sort(data)\n",
+    "        assert_equal(data, [])\n",
+    "\n",
+    "        print('One element')\n",
+    "        data = [5]\n",
+    "        insertion_sort(data)\n",
+    "        assert_equal(data, [5])\n",
+    "\n",
+    "        print('Two or more elements')\n",
+    "        data = [5, 1, 7, 2, 6, -3, 5, 7, -1]\n",
+    "        insertion_sort(data)\n",
+    "        assert_equal(data, sorted(data))\n",
+    "        \n",
+    "        print('Success: test_insertion_sort')\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    test = TestInsertionSort()\n",
+    "    test.test_insertion_sort()"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.10"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/sorting_searching/insertion_sort/insertion_sort_solution.ipynb b/sorting_searching/insertion_sort/insertion_sort_solution.ipynb
index 7d38833..36aadd3 100644
--- a/sorting_searching/insertion_sort/insertion_sort_solution.ipynb
+++ b/sorting_searching/insertion_sort/insertion_sort_solution.ipynb
@@ -28,7 +28,7 @@
     "\n",
     "*Problem statements are often intentionally ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
     "\n",
-    "* Are you looking for a naiive solution?\n",
+    "* Is a naiive solution sufficient?\n",
     "    * Yes"
    ]
   },
@@ -38,8 +38,8 @@
    "source": [
     "## Test Cases\n",
     "\n",
-    "* Empty input\n",
-    "* One element\n",
+    "* Empty input -> []\n",
+    "* One element -> [element]\n",
     "* Two or more elements"
    ]
   },
@@ -111,17 +111,17 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Empty input\n",
-      "One element\n",
-      "Two or more elements\n",
-      "Success: test_insertion_sort\n"
+      "Overwriting test_insertion_sort.py\n"
      ]
     }
    ],
    "source": [
+    "%%writefile test_insertion_sort.py\n",
     "from nose.tools import assert_equal\n",
     "\n",
-    "class Test(object):\n",
+    "\n",
+    "class TestInsertionSort(object):\n",
+    "    \n",
     "    def test_insertion_sort(self):\n",
     "        print('Empty input')\n",
     "        data = []\n",
@@ -141,9 +141,31 @@
     "        print('Success: test_insertion_sort')\n",
     "\n",
     "if __name__ == '__main__':\n",
-    "    test = Test()\n",
+    "    test = TestInsertionSort()\n",
     "    test.test_insertion_sort()"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Empty input\n",
+      "One element\n",
+      "Two or more elements\n",
+      "Success: test_insertion_sort\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_insertion_sort.py"
+   ]
   }
  ],
  "metadata": {
diff --git a/sorting_searching/insertion_sort/test_insertion_sort.py b/sorting_searching/insertion_sort/test_insertion_sort.py
new file mode 100644
index 0000000..71d1de3
--- /dev/null
+++ b/sorting_searching/insertion_sort/test_insertion_sort.py
@@ -0,0 +1,26 @@
+from nose.tools import assert_equal
+
+
+class TestInsertionSort(object):
+    
+    def test_insertion_sort(self):
+        print('Empty input')
+        data = []
+        insertion_sort(data)
+        assert_equal(data, [])
+
+        print('One element')
+        data = [5]
+        insertion_sort(data)
+        assert_equal(data, [5])
+
+        print('Two or more elements')
+        data = [5, 1, 7, 2, 6, -3, 5, 7, -1]
+        insertion_sort(data)
+        assert_equal(data, sorted(data))
+        
+        print('Success: test_insertion_sort')
+
+if __name__ == '__main__':
+    test = TestInsertionSort()
+    test.test_insertion_sort()
\ No newline at end of file