Problem: Source files contain no license info (#2455)

* Problem: Source files contain no license info

Solution: Add comments with SPDX license info to source files

* Python 3 files don't need # -*- coding: utf-8 -*-

acceptance/python/src/test_basic.py

@@ -1,3 +1,7 @@
+# Copyright BigchainDB GmbH and BigchainDB contributors
+# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
+# Code is Apache-2.0 and docs are CC-BY-4.0
+
 # # Basic Acceptance Test
 # Here we check that the primitives of the system behave as expected.
 # As you will see, this script tests basic stuff like:
@@ -36,7 +40,6 @@ def test_basic():
     # The two keypairs will be called—drum roll—Alice and Bob.
     alice, bob = generate_keypair(), generate_keypair()
 
-
     # ## Alice registers her bike in BigchainDB
     # Alice has a nice bike, and here she creates the "digital twin"
     # of her bike.
@@ -57,7 +60,6 @@ def test_basic():
     # a variable with a short and easy name
     bike_id = fulfilled_creation_tx['id']
 
-
     # Now she is ready to send it to the BigchainDB Network.
     sent_transfer_tx = bdb.transactions.send(fulfilled_creation_tx)
 
@@ -69,7 +71,6 @@ def test_basic():
     assert len(bdb.outputs.get(alice.public_key, spent=False)) == 1
     assert bdb.outputs.get(alice.public_key)[0]['transaction_id'] == bike_id
 
-
     # ## Alice transfers her bike to Bob
     # After registering her bike, Alice is ready to transfer it to Bob.
     # She needs to create a new `TRANSFER` transaction.

acceptance/python/src/test_divisible_asset.py

@@ -1,3 +1,7 @@
+# Copyright BigchainDB GmbH and BigchainDB contributors
+# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
+# Code is Apache-2.0 and docs are CC-BY-4.0
+
 # # Divisible assets integration testing
 # This test checks if we can successfully divide assets.
 # The script tests various things like:

acceptance/python/src/test_double_spend.py

@@ -1,3 +1,7 @@
+# Copyright BigchainDB GmbH and BigchainDB contributors
+# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
+# Code is Apache-2.0 and docs are CC-BY-4.0
+
 # # Double Spend testing
 # This test challenge the system with double spends.
 

acceptance/python/src/test_multiple_owners.py

@@ -1,3 +1,7 @@
+# Copyright BigchainDB GmbH and BigchainDB contributors
+# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
+# Code is Apache-2.0 and docs are CC-BY-4.0
+
 # # Multiple owners integration testing
 # This test checks if we can successfully create and transfer a transaction
 # with multiple owners.

acceptance/python/src/test_naughty_strings.py

@@ -1,3 +1,7 @@
+# Copyright BigchainDB GmbH and BigchainDB contributors
+# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
+# Code is Apache-2.0 and docs are CC-BY-4.0
+
 # ## Testing potentially hazardous strings
 # This test uses a library of `naughty` strings (code injections, weird unicode chars., etc.) as both keys and values.
 # We look for either a successful tx, or in the case that we use a naughty string as a key, and it violates some key
@@ -8,7 +12,8 @@
 # env variables.
 import os
 
-# Since the naughty strings get encoded and decoded in odd ways, we'll use a regex to sweep those details under the rug.
+# Since the naughty strings get encoded and decoded in odd ways,
+# we'll use a regex to sweep those details under the rug.
 import re
 
 # We'll use a nice library of naughty strings...

acceptance/python/src/test_stream.py

@@ -1,3 +1,7 @@
+# Copyright BigchainDB GmbH and BigchainDB contributors
+# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
+# Code is Apache-2.0 and docs are CC-BY-4.0
+
 # # Stream Acceptance Test
 # This test checks if the event stream works correctly. The basic idea of this
 # test is to generate some random **valid** transaction, send them to a