import random
from rotated_binary_search import find_pivot, search, count_rotations

def test_empty():
    assert find_pivot([]) == -1
    assert search([], 5) == -1
    assert count_rotations([]) == 0

def test_single():
    assert find_pivot([7]) == 0
    assert search([7], 7) == 0
    assert search([7], 3) == -1

def test_sorted_no_rotation():
    a = [1,2,3,4,5]
    assert find_pivot(a) == 0
    for t in a + [0,6]:
        idx = search(a, t)
        assert (idx == -1) == (t not in a)
        if idx != -1:
            assert a[idx] == t

def test_rotated():
    base = [1,2,3,4,5,6,7]
    for r in range(len(base)):
        arr = base[r:] + base[:r]
        expected_pivot = (len(base) - r) % len(base)
        assert find_pivot(arr) == expected_pivot, (r, find_pivot(arr), expected_pivot)
        assert count_rotations(arr) == expected_pivot
        for t in base:
            i = search(arr, t)
            assert i != -1 and arr[i] == t

def test_duplicates():
    arr = [2,2,2,3,3,1,1,2]
    # pivot should point at a minimum (value 1)
    p = find_pivot(arr)
    assert arr[p] == 1
    assert search(arr, 3) != -1
    assert search(arr, 9) == -1

def test_randomized():
    random.seed(7)
    for _ in range(2000):
        n = random.randint(0, 30)
        base = sorted(random.randint(-5,5) for _ in range(n))
        r = random.randrange(n) if n else 0
        arr = base[r:] + base[:r] if n else []
        p = find_pivot(arr)
        if n:
            assert arr[p] == min(arr)
        # search every element
        for t in set(base):
            i = search(arr, t)
            assert i == -1 or arr[i] == t
        # search absent
        assert search(arr, 10**9) == -1