diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_blockchain.py b/tests/test_blockchain.py
new file mode 100644
index 0000000..f2d85e1
--- /dev/null
+++ b/tests/test_blockchain.py
@@ -0,0 +1,104 @@
+import hashlib
+import json
+from unittest import TestCase
+
+from blockchain import Blockchain
+
+
+class BlockchainTestCase(TestCase):
+
+    def setUp(self):
+        self.blockchain = Blockchain()
+
+    def create_block(self, proof=123, previous_hash='abc'):
+        self.blockchain.new_block(proof, previous_hash)
+
+    def create_transaction(self, sender='a', recipient='b', amount=1):
+        self.blockchain.new_transaction(
+            sender=sender,
+            recipient=recipient,
+            amount=amount
+        )
+
+
+class TestRegisterNodes(BlockchainTestCase):
+
+    def test_valid_nodes(self):
+        blockchain = Blockchain()
+
+        blockchain.register_node('http://192.168.0.1:5000')
+
+        self.assertIn('192.168.0.1:5000', blockchain.nodes)
+
+    def test_malformed_nodes(self):
+        blockchain = Blockchain()
+
+        blockchain.register_node('http//192.168.0.1:5000')
+
+        self.assertNotIn('192.168.0.1:5000', blockchain.nodes)
+
+    def test_idempotency(self):
+        blockchain = Blockchain()
+
+        blockchain.register_node('http://192.168.0.1:5000')
+        blockchain.register_node('http://192.168.0.1:5000')
+
+        assert len(blockchain.nodes) == 1
+
+
+class TestBlocksAndTransactions(BlockchainTestCase):
+
+    def test_block_creation(self):
+        self.create_block()
+
+        latest_block = self.blockchain.last_block
+
+        # The genesis block is create at initialization, so the length should be 2
+        assert len(self.blockchain.chain) == 2
+        assert latest_block['index'] == 2
+        assert latest_block['timestamp'] is not None
+        assert latest_block['proof'] == 123
+        assert latest_block['previous_hash'] == 'abc'
+
+    def test_create_transaction(self):
+        self.create_transaction()
+
+        transaction = self.blockchain.current_transactions[-1]
+
+        assert transaction
+        assert transaction['sender'] == 'a'
+        assert transaction['recipient'] == 'b'
+        assert transaction['amount'] == 1
+
+    def test_block_resets_transactions(self):
+        self.create_transaction()
+
+        initial_length = len(self.blockchain.current_transactions)
+
+        self.create_block()
+
+        current_length = len(self.blockchain.current_transactions)
+
+        assert initial_length == 1
+        assert current_length == 0
+
+    def test_return_last_block(self):
+        self.create_block()
+
+        created_block = self.blockchain.last_block
+
+        assert len(self.blockchain.chain) == 2
+        assert created_block is self.blockchain.chain[-1]
+
+
+class TestHashingAndProofs(BlockchainTestCase):
+
+    def test_hash_is_correct(self):
+        self.create_block()
+
+        new_block = self.blockchain.last_block
+        new_block_json = json.dumps(self.blockchain.last_block, sort_keys=True).encode()
+        new_hash = hashlib.sha256(new_block_json).hexdigest()
+
+        assert len(new_hash) == 64
+        assert new_hash == self.blockchain.hash(new_block)