test_Selection.py

#!/usr/bin/env python
"""Test Selection Sort"""

import sys

from AlgsSedgewickWayne.Selection import Sort
from AlgsSedgewickWayne.testcode.ArrayHistory import chk
from AlgsSedgewickWayne.testcode.ArrayHistory import ArrayHistory
from AlgsSedgewickWayne.testcode.InputArgs import cli_get_array

def test_wk2_lec(prt=sys.stdout):
    """Example from week 2 lecture, "Selection Sort (6:59)" """
    # Give the array that results after the first 4 exchanges when
    # selection sorting the following array:
    arr = [int(i) for i in "7 10 5 3 8 4 2 9 6".split()]
    run(arr, 'SELECTION SORT', prt=prt)

def test_wk2_ex_selections_489125(prt=sys.stdout):
    """What results after the first 4 exchanges when selection sorting the given array"""
    # (seed = 183182)
    # Give the array that results after the first 4 exchanges when
    # selection sorting the following array:
    arr = [int(i) for i in "13 16 40 60 19 70 71 47 12 67".split()]
    run(arr, 'SELECTION SORT', prt=prt)

def test_wk2_q3a(prt=sys.stdout):
    """QUESTION: Any pair of items is compared no more than once during selection sort"""
    # QUESTION: Any pair of items is compared no more than once during selection sort.
    # ANSWER(FALSE): Consider the array { 2, 1, 0 }. Then, 2 and 1 are compared twice.
    run([2, 1, 0], 'SELECTION SORT', prt=prt)

def test_wk2_q3b(prt=sys.stdout):
    """QUESTION: An exchange in selection sort can decrease the number of inversions by 2+"""
    # QUESTION: An exchange in selection sort can decrease the number of inversions
    #   by two (or more).
    # ANSWER(TRUE): Consider the array { 3, 2, 1 }, which has 3 inversions.
    # The first exchange results in the array { 1, 2, 3 }, which has zero inversions.
    run([3, 2, 1], 'SELECTION SORT', prt=prt)

def test_wk2_q2a(prt=sys.stdout):
    """Test selection sort on words"""
    desc = 'SELECTION SORT WORDS'
    prt.write(f"\n{desc}\n")
    exp = "BECK BUSH DEVO EVE6 HOLE JAYZ KORN MIMS VAIN RATT TOTO PINK SADE NOFX SOAD WHAM"
    arr = "HOLE BUSH MIMS BECK WHAM SOAD NOFX TOTO VAIN RATT DEVO PINK SADE KORN JAYZ EVE6".split()
    ahistobj = ArrayHistory()
    Sort(arr, array_history=ahistobj)
    ahistobj.show(desc)
    for idx, arrhist in enumerate(ahistobj):
        if chk( arrhist[0], exp ):
            prt.write(f"MATCH {idx}\n")

def run(arr, desc=None, prt=sys.stdout):
    """Run Selection sort"""
    ahistobj = ArrayHistory()
    Sort(arr, array_history=ahistobj)
    if desc is None:
        desc = "SELECTION SORT"
    prt.write(f"{desc} RESULT {' '.join(str(e) for e in arr)}\n")
    ahistobj.prt()
    ahistobj.show(desc)

def run_all():
    """Run all tests."""
    test_wk2_lec()
    test_wk2_ex_selections_489125()
    test_wk2_q3a()
    test_wk2_q2a()

def cli():
    """Command line interface for variations of this test"""
    len_array = len(sys.argv)
    if len_array == 1:
        run_all()
    elif len_array == 2:
        run(cli_get_array())

if __name__ == '__main__':
    cli()