{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "import math"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "# a more general form of the function \n",
    "def sector_area(radius1, radius2, angle_deg):\n",
    "    angle_rad = (2 * math.pi / 360) * angle_deg # changing degrees to radians\n",
    "    area = 0.5 * (radius1**2 - radius2**2) * angle_rad\n",
    "    return area"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "def test_gt0():\n",
    "    for rad1, rad2, ang in [(2, 1, 30), (10, 5, 270)]:\n",
    "        assert sector_area(rad1, rad2, ang) > 0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def test_angle0():\n",
    "    assert sector_area(5, 1, 0) == 0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def test_full():\n",
    "    assert sector_area(5, 0, 360) == math.pi * 25"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "test_gt0()\n",
    "test_angle0()\n",
    "test_full()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
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