8-Queens Matrix is Stored using JSON/XML having first Queen placed, use back-tracking to place remaining Queens to generate final 8-queen's Matrix. Use suitable Software modeling, Design and testing methods. Justify the selection over other methods.

File: b1.py

import json
import unittest

class MyTestCases(unittest.TestCase):
        def test_positive(self):
                self.assertEqual(run("inp2.json"), True)
 def test_negative(self):
  self.assertEqual(run("inp3.json"), False)

def isattack(board,r,c):
 for i in range(r):
  if(board[i][c]==1):
   return True
 i=r-1
 j=c-1
 while i>=0 and j>=0:
  if(board[i][j]==1):
   return True
  i-=1
  j-=1
 
 i=r-1
 j=c+1
 while i>=0 and j<8:
  if(board[i][j]==1):
   return True
  i-=1
  j-=1
 return False


def solve(board,row):
 i=0
 while i<8:
  if (not isattack(board,row,i)):
   board[row][i]=1
   if row==7:
    return True
   else:
    if(solve(board,row+1)):
     return True
    else:
     board[row][i]=0
  i=i+1
 if i==8:
  return False

def run(filename):
 board=[[0 for x in range(8)] for x in range(8)]
 if __name__=='__main__':
  data=[]
  with open(filename, 'r') as f:
   data=json.load(f)
  if data["start"]>7 or data["start"]<0:
   print "Invalid input"
   return False #exit()
  board[0][data["start"]]=1
  if solve(board,1):
   print "8 Queens solved"
   print "Board Configuration"
   for i in range(8):
    for j in range(8):
     print str(board[i][j])+"  ",
    print "\n"
   return True
  else:
   print "8 Queens not solved"

run('inp1.json')
print "---TESTING---"
unittest.main()


File: inp1.json

{"start":2}

File: inp2.json

{"start":5}

File: inp3.json

{"start":9}


Output

ccpvg@ccpvg-HP-Compaq-4000-Pro-SFF-PC:~$ python b1.py
8 Queens solved
Board Configuration
0   0   1   0   0   0   0   0

0   0   0   0   1   0   0   0

0   0   0   0   0   0   1   0

1   0   0   0   0   0   0   0

0   0   0   1   0   0   0   0

0   1   0   0   0   0   0   0

0   0   0   0   0   0   0   1

0   0   0   0   0   1   0   0

---TESTING---
Invalid input
.8 Queens solved
Board Configuration
0   0   0   0   0   1   0   0

0   1   0   0   0   0   0   0

0   0   0   0   1   0   0   0

0   0   0   0   0   0   0   1

0   0   0   1   0   0   0   0

0   0   0   0   0   0   1   0

0   0   1   0   0   0   0   0

1   0   0   0   0   0   0   0

.
----------------------------------------------------------------------
Ran 2 tests in 0.002s

OK