     "source": [
      "## Unit Test"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "*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": 3,
     "metadata": {
      "collapsed": false
 
</s> remove     "<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>"
 </s> add     "<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges).</i></small>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Solution Notebook" </s> remove     "%run linked_list.py"
 </s> add     "%run ../linked_list/linked_list.py" </s> remove     "    test = Test()\n",
    "    test.test_find_loop_start()"
 </s> add     "    main()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Test: Empty list\n",
      "Test: Not a circular linked list: One element\n",
      "Test: Not a circular linked list: Two elements\n",
      "Test: Not a circular linked list: Three or more elements\n",
      "Test: General case: Circular linked list\n",
      "Success: test_find_loop_start\n"
     ]
    }
   ],
   "source": [
    "%run -i test_find_loop_start.py" </s> remove     "*Problem statements are often intentionally ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
 </s> add     "*Problem statements are sometimes ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n", </s> remove     "* This is a singly linked list?\n",
 </s> add     "* Is this a singly linked list?\n",
     "source": [
      "## Unit Test"
     ]
    },







    {
     "cell_type": "code",
     "execution_count": 3,
     "metadata": {
      "collapsed": false
keep keep keep keep replace replace replace replace replace replace replace keep keep keep keep keep
 Added find loop start challenge. 
linked_lists/find_loop_start/find_loop_start_solution.ipynb