Flask-Testing appears to not remove session in between client requests

broken_test.py

from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
from flask.ext.testing import TestCase

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db'
db = SQLAlchemy(app)
@app.route('/')
def index():
  u = db.session.query(User).first()
  print u.name # Prints 'joe' the first time, 'bob' the second.
  u.name = 'bob'
  return ''

class User(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  name = db.Column(db.String)

class SessionTest(TestCase):

  def create_app(self):
    return app

  def test_remove(self):
    db.drop_all()
    db.create_all()

    u = User()
    u.name = 'joe'
    db.session.add(u)
    db.session.commit()
    client = app.test_client()
    client.get('/')
    client.get('/')