Testing and Debugging Jupyter Notebooks

test_and_debug.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Testing and Debugging Jupyter Notebooks"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This is a code cell with a function that we will test and debug. If you uncomment the second last line the exectuion of a test case will halt just before the return statement and the [Python debugger](https://docs.python.org/3/library/pdb.html) (pdb) will start. You will get a pdb prompt that will allow you to inspect the values of a and b, step over lines, etc."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def add(a, b):\n",
    "    '''\n",
    "    This is the test:\n",
    "    >>> add(2, 2)\n",
    "    5\n",
    "    '''\n",
    "    #import pdb; pdb.set_trace() # Uncomment this line to start the PDB debugger at this point.\n",
    "    return a + b"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The next cell uses the [doctest module](https://docs.python.org/3.6/library/doctest.html) and runs the test case in the docstring of the `add()` function (and all other test cases in other docstrings if present). This cell will normally be the last one in a notebook."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Trying:\n",
      "    add(2, 2)\n",
      "Expecting:\n",
      "    5\n",
      "**********************************************************************\n",
      "File \"__main__\", line 4, in __main__.add\n",
      "Failed example:\n",
      "    add(2, 2)\n",
      "Expected:\n",
      "    5\n",
      "Got:\n",
      "    4\n",
      "1 items had no tests:\n",
      "    __main__\n",
      "**********************************************************************\n",
      "1 items had failures:\n",
      "   1 of   1 in __main__.add\n",
      "1 tests in 2 items.\n",
      "0 passed and 1 failed.\n",
      "***Test Failed*** 1 failures.\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "TestResults(failed=1, attempted=1)"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import doctest\n",
    "doctest.testmod(verbose=True)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The next cell uses the [unittest module](https://docs.python.org/3.6/library/unittest.html) to test the `add()` function. In the class `TestNotebook` we define one test case (`test_add`) for the `add()` function. The last line in the cell runs all test cases when the cell is executed. This cell will normally be the last one in a notebook."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "test_add (__main__.TestNotebook) ... FAIL\n",
      "\n",
      "======================================================================\n",
      "FAIL: test_add (__main__.TestNotebook)\n",
      "----------------------------------------------------------------------\n",
      "Traceback (most recent call last):\n",
      "  File \"<ipython-input-3-0e81fd1280b9>\", line 6, in test_add\n",
      "    self.assertEqual(add(2, 2), 5)\n",
      "AssertionError: 4 != 5\n",
      "\n",
      "----------------------------------------------------------------------\n",
      "Ran 1 test in 0.001s\n",
      "\n",
      "FAILED (failures=1)\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "<unittest.main.TestProgram at 0x7fd31837e438>"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import unittest\n",
    "\n",
    "class TestNotebook(unittest.TestCase):\n",
    "    \n",
    "    def test_add(self):\n",
    "        self.assertEqual(add(2, 2), 5)\n",
    "        \n",
    "\n",
    "unittest.main(argv=[''], verbosity=2, exit=False)"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python [conda root]",
   "language": "python",
   "name": "conda-root-py"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.5.4"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}