# A simple test of binary search algorithms

def bs_test(bs):
    """
    A test framework for a simple binary search procedure.  
    """

    errors = 0

    for size in range(0,33):
        vals = range(0,2*(size-1),2)
        # Test something that precedes everything
        index = bs(-1, vals)
        if (index != -1):
            print("ERROR!  For bs(-1,", list(vals), "), expected -1 and got", 
                  index)
            errors = errors + 1
        # Test values in the array
        for i in vals:
            index = bs(i, vals)
            if (index != i/2):
                print("ERROR!  For bs(", i, ",", list(vals), ") expected", 
                      int(i/2), "and got", index)
                errors = errors + 1
        # Test values in the array
        for i in vals:
            # Test values not in the array
            index = bs(i+1, vals)
            if (index != -1):
                print("ERROR!  For bs(-1,", list(vals), "), expected -1 and got", 
                      index)
                errors = errors + 1

    # Report results
    if (errors == 1):
        print("One error encountered.")
        return False
    elif (errors > 1):
        print(errors, "errors encountered.")
        return False
    else:
        return True