diff --git a/test/test_cli.rb b/test/test_cli.rb
new file mode 100644
index 0000000..1711049
--- /dev/null
+++ b/test/test_cli.rb
@@ -0,0 +1,95 @@
+require 'minitest/autorun'
+require 'prism'
+require 'tmpdir'
+require 'fileutils'
+
+class CliTest < Minitest::Test
+  def setup
+    @workdir = Dir.mktmpdir('prism-cli')
+    @cli = Prism::Cli.new(@workdir)
+  end
+
+  def teardown
+    FileUtils.remove_entry(@workdir)
+  end
+
+  def test_new_app_scaffolds_expected_files
+    app_dir = @cli.new_app('blog')
+    assert File.directory?(File.join(app_dir, 'app', 'controllers'))
+    assert File.directory?(File.join(app_dir, 'app', 'models'))
+    assert File.directory?(File.join(app_dir, 'db', 'migrate'))
+    assert File.file?(File.join(app_dir, 'app.rb'))
+    assert File.file?(File.join(app_dir, 'config.ru'))
+    assert File.file?(File.join(app_dir, 'app', 'views', 'layouts', 'application.erb'))
+    assert File.executable?(File.join(app_dir, 'bin', 'server'))
+  end
+
+  def test_new_app_boot_file_references_app_class
+    app_dir = @cli.new_app('blog')
+    content = File.read(File.join(app_dir, 'app.rb'))
+    assert_includes content, 'class Blog < Prism::Application'
+  end
+
+  def test_new_app_refuses_to_overwrite_existing_directory
+    @cli.new_app('blog')
+    assert_raises(Prism::Cli::UsageError) { @cli.new_app('blog') }
+  end
+
+  def test_generate_migration_for_create_table
+    path = @cli.generate_migration('create_posts', ['title:string', 'body:text'])
+    content = File.read(path)
+    assert_includes content, 'class CreatePosts < Prism::Orm::Migration'
+    assert_includes content, 'create_table :posts do |t|'
+    assert_includes content, 't.string :title'
+    assert_includes content, 't.text :body'
+    assert_includes content, 't.timestamps'
+    assert_includes content, 'drop_table :posts'
+  end
+
+  def test_generate_migration_filename_has_version_prefix
+    path = @cli.generate_migration('create_posts', [])
+    assert_match(/\A\d{14}_create_posts\.rb\z/, File.basename(path))
+  end
+
+  def test_generate_migration_avoids_version_collisions_within_the_same_second
+    first = @cli.generate_migration('create_posts', [])
+    second = @cli.generate_migration('create_comments', [])
+    first_version = File.basename(first).split('_', 2).first
+    second_version = File.basename(second).split('_', 2).first
+    refute_equal first_version, second_version
+  end
+
+  def test_generated_migration_actually_runs
+    path = @cli.generate_migration('create_widgets', ['name:string'])
+    store = Prism::Orm::Store.new(File.join(@workdir, 'test.pstore'))
+    Prism::Orm::Migrator.new(store, File.dirname(path)).migrate!
+    assert store.table_exists?(:widgets)
+    assert_includes store.columns(:widgets), 'name'
+  end
+
+  def test_generate_model_creates_model_and_migration
+    model_path, migration_path = @cli.generate_model('post', ['title:string'])
+    assert_includes File.read(model_path), 'class Post < Prism::Orm::Model'
+    assert_includes File.read(migration_path), 'create_table :posts do |t|'
+  end
+
+  def test_bin_prism_new_via_subprocess
+    lib_dir = File.expand_path('../lib', __dir__)
+    bin_path = File.expand_path('../bin/prism', __dir__)
+    ruby = File.join(RbConfig::CONFIG['bindir'], RbConfig::CONFIG['ruby_install_name'])
+    output = IO.popen([ruby, "-I#{lib_dir}", bin_path, 'new', 'shop'], chdir: @workdir, err: [:child, :out], &:read)
+    status = $?.exitstatus
+    assert_equal 0, status, output
+    assert File.file?(File.join(@workdir, 'shop', 'app.rb'))
+  end
+
+  def test_bin_prism_reports_usage_error_and_nonzero_exit
+    lib_dir = File.expand_path('../lib', __dir__)
+    bin_path = File.expand_path('../bin/prism', __dir__)
+    ruby = File.join(RbConfig::CONFIG['bindir'], RbConfig::CONFIG['ruby_install_name'])
+    output = IO.popen([ruby, "-I#{lib_dir}", bin_path, 'bogus'], chdir: @workdir, err: [:child, :out], &:read)
+    status = $?.exitstatus
+    refute_equal 0, status
+    assert_includes output, 'unknown command'
+  end
+end
diff --git a/test/test_integration.rb b/test/test_integration.rb
new file mode 100644
index 0000000..61c8181
--- /dev/null
+++ b/test/test_integration.rb
@@ -0,0 +1,53 @@
+require 'minitest/autorun'
+require 'prism'
+require 'net/http'
+
+class IntegrationApp < Prism::Application
+  get '/ping' do
+    json(pong: true)
+  end
+
+  get '/hello/:name' do
+    json(hello: params['name'])
+  end
+
+  post '/sum' do
+    numbers = JSON.parse(request.body)
+    json(sum: numbers['a'] + numbers['b'])
+  end
+end
+
+class IntegrationTest < Minitest::Test
+  def setup
+    @server = Prism::Server.new(IntegrationApp, port: 0).start
+    @port = @server.port
+  end
+
+  def teardown
+    @server.stop
+  end
+
+  def test_port_is_ephemeral
+    assert @port.positive?
+  end
+
+  def test_get_with_param
+    response = Net::HTTP.get_response(URI("http://127.0.0.1:#{@port}/hello/Ruby"))
+    assert_equal '200', response.code
+    assert_equal({ 'hello' => 'Ruby' }, JSON.parse(response.body))
+  end
+
+  def test_post_with_body
+    uri = URI("http://127.0.0.1:#{@port}/sum")
+    response = Net::HTTP.start(uri.host, uri.port) do |http|
+      http.post(uri.path, JSON.generate(a: 2, b: 40), 'Content-Type' => 'application/json')
+    end
+    assert_equal '200', response.code
+    assert_equal 42, JSON.parse(response.body)['sum']
+  end
+
+  def test_not_found_over_http
+    response = Net::HTTP.get_response(URI("http://127.0.0.1:#{@port}/nope"))
+    assert_equal '404', response.code
+  end
+end
diff --git a/test/test_integration_orm.rb b/test/test_integration_orm.rb
new file mode 100644
index 0000000..024a398
--- /dev/null
+++ b/test/test_integration_orm.rb
@@ -0,0 +1,88 @@
+require 'minitest/autorun'
+require 'prism'
+require 'net/http'
+require 'tmpdir'
+require 'fileutils'
+
+class IntegrationOrmTest < Minitest::Test
+  def setup
+    @dir = Dir.mktmpdir('prism-e2e-orm')
+    @db_path = File.join(@dir, 'blog.pstore')
+    @views_dir = File.join(@dir, 'views', 'e2e_posts')
+    FileUtils.mkdir_p(@views_dir)
+    File.write(File.join(@views_dir, 'index.erb'), <<~ERB)
+      <ul class="posts">
+      <% posts.each do |post| %>
+      <li><%= post.title %>: <%= post.body %></li>
+      <% end %>
+      </ul>
+    ERB
+
+    Prism::Orm.connect(@db_path)
+    Prism::Orm.store.create_table(:e2e_posts, %w[id title body created_at updated_at])
+
+    views_dir = File.dirname(@views_dir)
+    post_class = Class.new(Prism::Orm::Model) do
+      table_name :e2e_posts
+      validates :title, presence: true
+    end
+    Object.const_set(:E2ePost, post_class)
+
+    controller_class = Class.new(Prism::Controller) do
+      views_root views_dir
+
+      define_method(:index) { render(:index, locals: { posts: E2ePost.order(:id) }) }
+      define_method(:create) do
+        post = E2ePost.create(title: params['title'], body: params['body'])
+        json({ id: post.id }, 201)
+      end
+    end
+    Object.const_set(:E2ePostsController, controller_class)
+
+    app_class = Class.new(Prism::Application) do
+      get '/posts', to: 'e2e_posts#index'
+      post '/posts', to: 'e2e_posts#create'
+    end
+    Object.const_set(:E2eBlogApp, app_class)
+  end
+
+  def teardown
+    @server&.stop
+    %i[E2ePost E2ePostsController E2eBlogApp].each { |name| Object.send(:remove_const, name) if Object.const_defined?(name) }
+    FileUtils.remove_entry(@dir)
+  end
+
+  def test_post_then_get_round_trip_and_survives_a_process_restart
+    @server = Prism::Server.new(E2eBlogApp, port: 0).start
+    port = @server.port
+
+    create_response = Net::HTTP.start('127.0.0.1', port) do |http|
+      http.post('/posts', URI.encode_www_form(title: 'Hello Prism', body: 'first real post'),
+                 'Content-Type' => 'application/x-www-form-urlencoded')
+    end
+    assert_equal '201', create_response.code
+    created_id = JSON.parse(create_response.body)['id']
+    refute_nil created_id
+
+    listing_response = Net::HTTP.get_response(URI("http://127.0.0.1:#{port}/posts"))
+    assert_equal '200', listing_response.code
+    assert_includes listing_response.body, 'Hello Prism: first real post'
+
+    @server.stop
+    @server = nil
+
+    # Simulate a process restart: reconnect to the same file with a brand new
+    # Store instance (no shared in-memory state with the writer above) and
+    # boot a second, independent server against it.
+    Prism::Orm.connect(@db_path)
+    restarted_server = Prism::Server.new(E2eBlogApp, port: 0).start
+    begin
+      restarted_response = Net::HTTP.get_response(URI("http://127.0.0.1:#{restarted_server.port}/posts"))
+      assert_equal '200', restarted_response.code
+      assert_includes restarted_response.body, 'Hello Prism: first real post',
+                       'data inserted before the restart must still render after reconnecting to the store file'
+    ensure
+      restarted_server.stop
+    end
+  end
+end