def test_distribution():
    rng = check_random_state(12321)

    # Single variable with 4 values
    X = rng.randint(0, 4, size=(1000, 1))
    y = rng.rand(1000)
    n_trees = 500

    clf = ExtraTreesRegressor(n_estimators=n_trees, random_state=42).fit(X, y)

    uniques = defaultdict(int)
    for tree in clf.estimators_:
        tree = "".join(("%d,%d/" % (f, int(t)) if f >= 0 else "-")
                       for f, t in zip(tree.tree_.feature,
                                       tree.tree_.threshold))

        uniques[tree] += 1

    uniques = sorted([(1. * count / n_trees, tree)
                      for tree, count in uniques.items()])

    # On a single variable problem where X_0 has 4 equiprobable values, there
    # are 5 ways to build a random tree. The more compact (0,1/0,0/--0,2/--) of
    # them has probability 1/3 while the 4 others have probability 1/6.

    assert_equal(len(uniques), 5)
    assert_greater(0.20, uniques[0][0])  # Rough approximation of 1/6.
    assert_greater(0.20, uniques[1][0])
    assert_greater(0.20, uniques[2][0])
    assert_greater(0.20, uniques[3][0])
    assert_greater(uniques[4][0], 0.3)
    assert_equal(uniques[4][1], "0,1/0,0/--0,2/--")

    # Two variables, one with 2 values, one with 3 values
    X = np.empty((1000, 2))
    X[:, 0] = np.random.randint(0, 2, 1000)
    X[:, 1] = np.random.randint(0, 3, 1000)
    y = rng.rand(1000)

    clf = ExtraTreesRegressor(n_estimators=100, max_features=1,
                              random_state=1).fit(X, y)

    uniques = defaultdict(int)
    for tree in clf.estimators_:
        tree = "".join(("%d,%d/" % (f, int(t)) if f >= 0 else "-")
                       for f, t in zip(tree.tree_.feature,
                                       tree.tree_.threshold))

        uniques[tree] += 1

    uniques = [(count, tree) for tree, count in uniques.items()]
    assert_equal(len(uniques), 8)
dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/ensemble/tests/test_forest.py/test_distribution/original