diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..1991e5d
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,12 @@
+language: python
+
+python:
+  - 3.6
+  - nightly
+
+install:
+  - pip install pipenv
+  - pipenv install --dev
+
+script:
+  - pipenv run python -m unittest
diff --git a/README.md b/README.md
index 0f46b5b..e77626b 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,7 @@
 # Learn Blockchains by Building One
 
+[![Build Status](https://travis-ci.org/dvf/blockchain.svg?branch=master)](https://travis-ci.org/dvf/blockchain)
+
 This is the source code for my post on [Building a Blockchain](https://medium.com/p/117428612f46). 
 
 ## Installation
diff --git a/blockchain.py b/blockchain.py
index cb1cb8a..aba163b 100644
--- a/blockchain.py
+++ b/blockchain.py
@@ -1,7 +1,6 @@
 import hashlib
 import json
 from time import time
-from typing import Any, Dict, List, Optional
 from urllib.parse import urlparse
 from uuid import uuid4
 
@@ -18,7 +17,7 @@ class Blockchain:
         # Create the genesis block
         self.new_block(previous_hash='1', proof=100)
 
-    def register_node(self, address: str) -> None:
+    def register_node(self, address):
         """
         Add a new node to the list of nodes
 
@@ -28,7 +27,7 @@ class Blockchain:
         parsed_url = urlparse(address)
         self.nodes.add(parsed_url.netloc)
 
-    def valid_chain(self, chain: List[Dict[str, Any]]) -> bool:
+    def valid_chain(self, chain):
         """
         Determine if a given blockchain is valid
 
@@ -57,7 +56,7 @@ class Blockchain:
 
         return True
 
-    def resolve_conflicts(self) -> bool:
+    def resolve_conflicts(self):
         """
         This is our consensus algorithm, it resolves conflicts
         by replacing our chain with the longest one in the network.
@@ -91,7 +90,7 @@ class Blockchain:
 
         return False
 
-    def new_block(self, proof: int, previous_hash: Optional[str]) -> Dict[str, Any]:
+    def new_block(self, proof, previous_hash):
         """
         Create a new Block in the Blockchain
 
@@ -114,7 +113,7 @@ class Blockchain:
         self.chain.append(block)
         return block
 
-    def new_transaction(self, sender: str, recipient: str, amount: int) -> int:
+    def new_transaction(self, sender, recipient, amount):
         """
         Creates a new transaction to go into the next mined Block
 
@@ -132,11 +131,11 @@ class Blockchain:
         return self.last_block['index'] + 1
 
     @property
-    def last_block(self) -> Dict[str, Any]:
+    def last_block(self):
         return self.chain[-1]
 
     @staticmethod
-    def hash(block: Dict[str, Any]) -> str:
+    def hash(block):
         """
         Creates a SHA-256 hash of a Block
 
@@ -147,7 +146,7 @@ class Blockchain:
         block_string = json.dumps(block, sort_keys=True).encode()
         return hashlib.sha256(block_string).hexdigest()
 
-    def proof_of_work(self, last_proof: int) -> int:
+    def proof_of_work(self, last_proof):
         """
         Simple Proof of Work Algorithm:
          - Find a number p' such that hash(pp') contains leading 4 zeroes, where p is the previous p'
@@ -161,7 +160,7 @@ class Blockchain:
         return proof
 
     @staticmethod
-    def valid_proof(last_proof: int, proof: int) -> bool:
+    def valid_proof(last_proof, proof):
         """
         Validates the Proof
 
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)