diff --git a/bank_api/app.py b/bank_api/app.py
index 948b973..db02122 100644
--- a/bank_api/app.py
+++ b/bank_api/app.py
@@ -2,6 +2,7 @@
 from flask_restx import Api, Resource, reqparse, fields, abort
 
 from bank_api.bank import Bank
+from bank_api.bank_report import BankReport
 
 
 def create_app():
@@ -11,6 +12,7 @@ def create_app():
     api = Api(app, title='My Banking API',
             description='A simple banking API for learning Test-Driven-Development')
     bank = Bank()
+    bank_report = BankReport(bank)
 
     # Custom API documentation
     add_money = api.model("Add", {
@@ -31,7 +33,8 @@ def post(self, name):
         def get(self, name):
             """Get an Account"""
             try:
-                return bank.get_account(name).to_dict()
+                account = bank.get_account(name)
+                return {**account.to_dict(), 'balance': bank_report.get_balance(name)}
             except Exception:
                 abort(404, 'Account not found')
 
diff --git a/bank_api/bank.py b/bank_api/bank.py
index afe6353..2e003af 100644
--- a/bank_api/bank.py
+++ b/bank_api/bank.py
@@ -45,6 +45,8 @@ def get_account(self, name: str) -> Account:
 
     def add_funds(self, name: str, amount: int) -> None:
         """Add funds to the named account"""
+        if amount <= 0:
+            raise ValueError("Amount must be a positive integer")
         account = self.get_account(name)
         now = datetime.now()
         self.transactions.append(Transaction(account, now, amount))
diff --git a/bank_api/bank_report.py b/bank_api/bank_report.py
new file mode 100644
index 0000000..380ed96
--- /dev/null
+++ b/bank_api/bank_report.py
@@ -0,0 +1,10 @@
+from bank_api.bank import Bank
+
+
+class BankReport:
+    def __init__(self, bank: Bank):
+        self.bank = bank
+
+    def get_balance(self, name: str) -> int:
+        account = self.bank.get_account(name)
+        return sum(t.amount for t in self.bank.transactions if t.account == account)
diff --git a/tests/test_app.py b/tests/test_app.py
index e05b062..aa0e107 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -16,8 +16,28 @@ def client():
 
 
 def test_account_creation(client: FlaskClient):
-    # Use the client to make requests to the Flask app.
-    # response = client.get('/example/route')
-    # Or use client.post to make a POST request
-    # https://flask.palletsprojects.com/en/1.1.x/testing/
-    pass
+    post_response = client.post('/accounts/Alice')
+
+    assert post_response.status_code == 200
+    assert post_response.get_json() == {"name": "Alice"}
+
+    get_response = client.get('/accounts/Alice')
+
+    assert get_response.status_code == 200
+    assert get_response.get_json() == {"name": "Alice", "balance": 0}
+
+
+def test_get_account_returns_404_if_not_found(client: FlaskClient):
+    response = client.get('/accounts/Nobody')
+
+    assert response.status_code == 404
+
+
+def test_get_account_includes_balance(client: FlaskClient):
+    client.post('/accounts/Alice')
+    client.post('/money', json={'name': 'Alice', 'amount': 1000})
+
+    response = client.get('/accounts/Alice')
+
+    assert response.status_code == 200
+    assert response.get_json()['balance'] == 1000
diff --git a/tests/test_bank.py b/tests/test_bank.py
index 0f106f0..170c7db 100644
--- a/tests/test_bank.py
+++ b/tests/test_bank.py
@@ -32,5 +32,33 @@ def test_get_account_raises_error_if_no_account_matches(bank: Bank):
     with pytest.raises(ValueError):
         bank.get_account('Name 2')
 
-# TODO: Add unit tests for bank.add_funds()
+# --- add_funds() tests ---
+
+def test_add_funds_creates_transaction(bank: Bank):
+    bank.create_account('Alice')
+    bank.add_funds('Alice', 1000)
+
+    assert len(bank.transactions) == 1
+
+def test_add_funds_transaction_has_correct_amount(bank: Bank):
+    bank.create_account('Alice')
+    bank.add_funds('Alice', 500)
+
+    assert bank.transactions[0].amount == 500
+
+def test_add_funds_raises_error_if_account_not_found(bank: Bank):
+    with pytest.raises(ValueError):
+        bank.add_funds('Nobody', 100)
+
+def test_add_funds_raises_error_if_amount_is_negative(bank: Bank):
+    bank.create_account('Alice')
+
+    with pytest.raises(ValueError):
+        bank.add_funds('Alice', -50)
+
+def test_add_funds_raises_error_if_amount_is_zero(bank: Bank):
+    bank.create_account('Alice')
+
+    with pytest.raises(ValueError):
+        bank.add_funds('Alice', 0)
 
diff --git a/tests/test_bank_report.py b/tests/test_bank_report.py
new file mode 100644
index 0000000..bd396e7
--- /dev/null
+++ b/tests/test_bank_report.py
@@ -0,0 +1,47 @@
+"""Unit tests for bank_report.py"""
+
+from datetime import datetime
+
+import pytest
+
+from bank_api.bank import Account, Bank, Transaction
+from bank_api.bank_report import BankReport
+
+
+@pytest.fixture
+def bank() -> Bank:
+    return Bank()
+
+
+def test_balance_is_zero_with_no_transactions(bank: Bank, monkeypatch):
+    bank_report = BankReport(bank)
+    account = Account('Alice')
+    monkeypatch.setattr(bank, 'get_account', lambda name: account)
+    monkeypatch.setattr(bank, 'transactions', [])
+
+    assert bank_report.get_balance('Alice') == 0
+
+
+def test_balance_sums_transactions(bank: Bank, monkeypatch):
+    bank_report = BankReport(bank)
+    account = Account('Alice')
+    monkeypatch.setattr(bank, 'get_account', lambda name: account)
+    monkeypatch.setattr(bank, 'transactions', [
+        Transaction(account, datetime.now(), 500),
+        Transaction(account, datetime.now(), 300),
+    ])
+
+    assert bank_report.get_balance('Alice') == 800
+
+
+def test_balance_ignores_other_accounts_transactions(bank: Bank, monkeypatch):
+    bank_report = BankReport(bank)
+    alice = Account('Alice')
+    bob = Account('Bob')
+    monkeypatch.setattr(bank, 'get_account', lambda name: alice)
+    monkeypatch.setattr(bank, 'transactions', [
+        Transaction(alice, datetime.now(), 1000),
+        Transaction(bob, datetime.now(), 200),
+    ])
+
+    assert bank_report.get_balance('Alice') == 1000