def test_or1():
    circuit = Circuit('OR',False, True)
    assert circuit.eval({}) == True

def test_or2():
    circuit = Circuit('OR',False, 'x')
    assert circuit.eval({'x' : True}) == True

def test_and1():
    circuit = Circuit('AND', True, 'x')
    assert circuit.eval({'x' : True}) == True
    assert circuit.eval({'x' : False}) == False

def test_not1():
    circuit = Circuit('NOT', 'x')
    assert circuit.eval({'x' : True}) == False
    assert circuit.eval({'x' : False}) == True

def test_demorgan():
    circuit1 = Circuit('NOT', Circuit('AND','x','y'))
    circuit2 = Circuit('OR', Circuit('NOT','x'), Circuit('NOT','y'))
    for x,y in [(False, False), (False, True), (True, False), (True, True)]:
        assert circuit1.eval({'x': x, 'y': y}) == \
            circuit2.eval({'x': x, 'y': y})

def test_xor():
    circuit = Circuit('AND', Circuit('OR','x','y'),
                      Circuit('OR', Circuit('NOT','x'), Circuit('NOT','y')))
    assert circuit.eval({'x' : True, 'y' : True})==False
    assert circuit.eval({'x' : True, 'y' : False})==True

def test_list():
    nodes = 256
    circuit=Circuit('NOT', f'y{nodes-1}')
    for j in range(0,nodes-1):
        circuit = Circuit('OR', f'y{j}', circuit)

    assert circuit.eval({f'y{j}' : False for j in range(nodes)}) == True
    assert circuit.eval({f'y{j}' : (j>=nodes-1) for j in range(nodes)}) == False

def test_tree1():
    circuit=tree(2)
    assert circuit == Circuit('AND',
                              Circuit('AND', Circuit('NOT', 'x0'),
                                      Circuit('NOT', 'x1')),
                              Circuit('AND', Circuit('NOT', 'x2'),
                                      Circuit('NOT', 'x3')))
def test_tree2():
    levels = 8
    circuit = tree(levels)
    assert circuit.eval({f'x{j}' : False for j in range(2**levels)})
    assert not circuit.eval({f'x{j}' : (j<1) for j in range(2**levels)})

import pytest
# undefined variable
def test_or4():
    circuit = Circuit('OR','x', True )
    with pytest.raises(RuntimeError) as e:
        circuit.eval({}) == True

# bad operator
def test_and5():
    circuit = Circuit('MAYBE','x', True )
    with pytest.raises(ValueError) as e:
        circuit.eval({}) == True