Added columns property to chunks matrix

Added test for columns

da/common.py

@@ -20,9 +20,9 @@ class Row(List[Chunk]):
 
 
 class ChunksMatrix(List[Row]):
+    @property
     def columns(self) -> Generator[List[Chunk], None, None]:
-        # TODO: yield columns
-        yield None
+        yield from map(list, zip(*self))
 
 
 

da/dispersal.py

@@ -13,7 +13,7 @@ class Dispersal:
     def _prepare_data(self, encoded_data: EncodedData) -> Generator[DABlob, None, None]:
         assert len(encoded_data.row_commitments) == len(self.nodes)
         assert len(encoded_data.row_proofs) == len(self.nodes)
-        columns = encoded_data.extended_matrix.columns()
+        columns = encoded_data.extended_matrix.columns
         column_commitments = encoded_data.column_commitments
         row_commitments = encoded_data.row_commitments
         rows_proofs = encoded_data.row_proofs

da/encoder.py

@@ -3,7 +3,7 @@ from typing import List
 from eth2spec.eip7594.mainnet import KZGCommitment as Commitment, KZGProof as Proof
 
 from da.common import ChunksMatrix
-
+from da.kzg_rs import kzg, rs, poly
 
 @dataclass
 class DAEncoderParams:

da/test_common.py

@@ -0,0 +1,12 @@
+from unittest import TestCase
+
+from da.common import ChunksMatrix
+
+
+class TestCommon(TestCase):
+
+    def test_chunks_matrix_columns(self):
+        matrix = ChunksMatrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
+        expected = [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
+        for c1, c2 in zip(expected, matrix.columns):
+            self.assertEqual(c1, c2)