GDScript BFS

#var visited = [] # List to keep track of visited nodes.
var queue = []     #Initialize a queue

func bfs(visited, graph, node):
    var result = []
    visited.append(node)
    queue.append(node)

    while queue:
        var s = queue.pop_front()
        result.append(s)

        for neighbour in graph[s]:
            if not visited.has(neighbour):
                visited.append(neighbour)
                queue.append(neighbour)
    return result

var graph1 = {
    'A' : ['B','C'],
    'B' : ['D', 'E'],
    'C' : ['F'],
    'D' : [],
    'E' : ['F'],
    'F' : []
    }

var graph2 = {
    '0': ['1', '2'],
    '1': ['2'],
    '2': ['0', '3'],
    '3': ['3']
    }

var graph3 = {
    0:[1,3,4],
    1:[0,2,4],
    2:[1,6],
    3:[0,4,6],
    4:[0,1,3,5],
    5:[4],
    6:[2,3]
}

func test():
    print(bfs([], graph1, 'A') == ['A', 'B', 'C', 'D', 'E', 'F'])
    print(bfs([], graph2, '2') == ['2', '0', '3', '1'])
    print(bfs([], graph3, 0) == [0, 1, 3, 4, 2, 6, 5])
    print(bfs([], graph3, 1) != [0, 1, 3, 4, 2, 6, 5])