Reworked notebook: Added more detail to constraints and test cases. Reworked code and unit test.

sorting-searching/selection-sort.ipynb

@@ -13,20 +13,22 @@
    "source": [
     "## Problem: Implement selection sort.\n",
     "\n",
-    "* [Clarifying Questions](#Clarifying-Questions)\n",
+    "* [Constraints and Assumptions](#Constraints-and-Assumptions)\n",
     "* [Test Cases](#Test-Cases)\n",
     "* [Algorithm](#Algorithm)\n",
     "* [Code](#Code)\n",
-    "* [Pythonic-Code](#Pythonic-Code)"
+    "* [Unit Test](#Unit-Test)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Clarifying Questions\n",
+    "## Constraints and Assumptions\n",
     "\n",
-    "* Are you looking for a generic naiive selection sort (ie not stable)?\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 (ie not stable, not based on a heap)?\n",
     "    * Yes"
    ]
   },
@@ -70,7 +72,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {
     "collapsed": true
    },
@@ -90,34 +92,21 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 2,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
-    "def selection_sort_recursive(data, start):\n",
+    "def selection_sort_recursive(data, start=0):\n",
     "    if start < len(data) - 1:\n",
     "        swap(data, start, find_min_index(data, start))\n",
-    "        selection_sort_recursive(data, start+1)\n",
+    "        selection_sort_recursive(data, start+1)"
-    "\n",
-    "print('Empty input')\n",
-    "data = []\n",
-    "selection_sort_recursive(data, 0)\n",
-    "print(data)\n",
-    "print('One element')\n",
-    "data = [5]\n",
-    "selection_sort_recursive(data, 0)\n",
-    "print(data)\n",
-    "print('Two or more elements')\n",
-    "data = [5, 1, 7, 2, 6, -3, 5, 7, -1]\n",
-    "selection_sort_recursive(data, 0)\n",
-    "print(data)"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 3,
    "metadata": {
     "collapsed": false
    },
@@ -129,6 +118,67 @@
     "    for i in xrange(0, len(data) - 1):\n",
     "        swap(data, i, find_min_index(data, i))"
    ]
+  },
+  {
+   "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.*"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Empty input\n",
+      "One element\n",
+      "Two or more elements\n",
+      "Success: test_selection_sort\n",
+      "\n",
+      "Empty input\n",
+      "One element\n",
+      "Two or more elements\n",
+      "Success: test_selection_sort\n",
+      "\n"
+     ]
+    }
+   ],
+   "source": [
+    "from nose.tools import assert_equal\n",
+    "\n",
+    "class Test(object):\n",
+    "    def test_selection_sort(self, func):\n",
+    "        print('Empty input')\n",
+    "        data = []\n",
+    "        func(data)\n",
+    "        assert_equal(data, [])\n",
+    "\n",
+    "        print('One element')\n",
+    "        data = [5]\n",
+    "        func(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",
+    "        func(data)\n",
+    "        assert_equal(data, sorted(data))\n",
+    "        \n",
+    "        print('Success: test_selection_sort\\n')\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    test = Test()\n",
+    "    test.test_selection_sort(selection_sort_recursive)\n",
+    "    test.test_selection_sort(selection_sort_iterative)"
+   ]
   }
  ],
  "metadata": {