Add unit tests for elemnet featurizer

import unittest

import numpy as np

from deepchem.feat import ElementPropertyFingerprint, SineCoulombMatrix, CGCNNFeaturizer

from deepchem.feat import ElementPropertyFingerprint, SineCoulombMatrix, CGCNNFeaturizer, ElemNetFeaturizer

class TestMaterialFeaturizers(unittest.TestCase):

    assert graph_features[0].node_features.shape == (1, 92)

    assert graph_features[0].edge_index.shape == (2, 6)

    assert graph_features[0].edge_features.shape == (6, 11)

  def test_elemnet_featurizer(self):

    """

    Test ElemNetFeaturizer.

    """

    featurizer = ElemNetFeaturizer()

    features = featurizer.featurize([self.formula])

    assert features.shape[1] == 86

    assert np.isclose(features[0][13], 0.6666667, atol=0.01)

    assert np.isclose(features[0][38], 0.33333334, atol=0.01)

    assert np.isclose(features.sum(), 1.0, atol=0.01)