test: cover MiddlewareCorsTest and teardown

test/test_middleware_cors.rb

@@ -0,0 +1,150 @@
+require 'minitest/autorun'
+require 'prism'
+require 'support'
+
+class MiddlewareCorsTest < Minitest::Test
+  include TestSupport
+
+  def setup
+    Prism::Cors.reset!
+    @downstream_calls = 0
+    downstream = lambda do |_env|
+      @downstream_calls += 1
+      [200, {'Content-Type' => 'application/json'}, ['{}']]
+    end
+    @app = Prism::Middleware::Cors.new(downstream)
+  end
+
+  def teardown
+    Prism::Cors.reset!
+  end
+
+  def configure_api(**resource_options)
+    Prism::Cors.configure do |config|
+      config.allow do
+        origins 'https://app.example.com'
+        resource '/api/*', **resource_options
+      end
+    end
+  end
+
+  def test_request_without_origin_header_passes_through_untouched
+    status, headers, = @app.call(env_for('GET', '/api/posts'))
+    assert_equal 200, status
+    assert_nil headers['Access-Control-Allow-Origin']
+    assert_equal 1, @downstream_calls
+  end
+
+  def test_request_with_unmatched_origin_passes_through_without_cors_headers
+    configure_api(methods: %w[GET])
+    env = env_for('GET', '/api/posts', headers: {'Origin' => 'https://evil.example.com'})
+    status, headers, = @app.call(env)
+    assert_equal 200, status
+    assert_nil headers['Access-Control-Allow-Origin']
+    assert_equal 1, @downstream_calls
+  end
+
+  def test_simple_request_with_allowed_origin_gets_cors_headers_and_reaches_the_app
+    configure_api(methods: %w[GET])
+    env = env_for('GET', '/api/posts', headers: {'Origin' => 'https://app.example.com'})
+    status, headers, = @app.call(env)
+
+    assert_equal 200, status
+    assert_equal 'https://app.example.com', headers['Access-Control-Allow-Origin']
+    assert_equal 'Origin', headers['Vary']
+    assert_equal 1, @downstream_calls
+  end
+
+  def test_preflight_request_is_answered_directly_without_reaching_the_app
+    configure_api(methods: %w[GET POST], headers: %w[Content-Type])
+    env = env_for('OPTIONS', '/api/posts', headers: {
+      'Origin' => 'https://app.example.com',
+      'Access-Control-Request-Method' => 'POST',
+      'Access-Control-Request-Headers' => 'Content-Type'
+    })
+    status, headers, body = @app.call(env)
+
+    assert_equal 204, status
+    assert_equal 'https://app.example.com', headers['Access-Control-Allow-Origin']
+    assert_equal 'GET, POST', headers['Access-Control-Allow-Methods']
+    assert_equal 'Content-Type', headers['Access-Control-Allow-Headers']
+    assert_empty body
+    assert_equal 0, @downstream_calls
+  end
+
+  def test_preflight_with_disallowed_method_is_rejected
+    configure_api(methods: %w[GET])
+    env = env_for('OPTIONS', '/api/posts', headers: {
+      'Origin' => 'https://app.example.com',
+      'Access-Control-Request-Method' => 'DELETE'
+    })
+    status, = @app.call(env)
+
+    assert_equal 403, status
+    assert_equal 0, @downstream_calls
+  end
+
+  def test_preflight_with_disallowed_header_is_rejected
+    configure_api(methods: %w[POST], headers: %w[Content-Type])
+    env = env_for('OPTIONS', '/api/posts', headers: {
+      'Origin' => 'https://app.example.com',
+      'Access-Control-Request-Method' => 'POST',
+      'Access-Control-Request-Headers' => 'X-Secret'
+    })
+    status, = @app.call(env)
+
+    assert_equal 403, status
+  end
+
+  def test_max_age_is_only_sent_when_configured
+    configure_api(methods: %w[GET], max_age: 600)
+    env = env_for('OPTIONS', '/api/posts', headers: {
+      'Origin' => 'https://app.example.com',
+      'Access-Control-Request-Method' => 'GET'
+    })
+    _, headers, = @app.call(env)
+    assert_equal '600', headers['Access-Control-Max-Age']
+  end
+
+  def test_credentials_true_echoes_origin_and_sets_allow_credentials
+    configure_api(methods: %w[GET], credentials: true)
+    env = env_for('GET', '/api/posts', headers: {'Origin' => 'https://app.example.com'})
+    _, headers, = @app.call(env)
+
+    assert_equal 'https://app.example.com', headers['Access-Control-Allow-Origin']
+    assert_equal 'true', headers['Access-Control-Allow-Credentials']
+  end
+
+  def test_expose_headers_only_sent_when_configured
+    configure_api(methods: %w[GET], expose: %w[X-Total-Count])
+    env = env_for('GET', '/api/posts', headers: {'Origin' => 'https://app.example.com'})
+    _, headers, = @app.call(env)
+    assert_equal 'X-Total-Count', headers['Access-Control-Expose-Headers']
+  end
+
+  def test_vary_origin_is_appended_to_an_existing_vary_header
+    Prism::Cors.reset!
+    downstream = lambda { |_env| [200, {'Vary' => 'Accept'}, ['{}']] }
+    app = Prism::Middleware::Cors.new(downstream)
+    configure_api(methods: %w[GET])
+    env = env_for('GET', '/api/posts', headers: {'Origin' => 'https://app.example.com'})
+    _, headers, = app.call(env)
+    assert_equal 'Accept, Origin', headers['Vary']
+  end
+
+  def test_a_resource_registered_without_a_format_extension_still_matches_a_dot_json_path
+    configure_api(methods: %w[GET])
+    env = env_for('GET', '/api/posts.json', headers: {'Origin' => 'https://app.example.com'})
+    status, headers, = @app.call(env)
+    assert_equal 200, status
+    assert_equal 'https://app.example.com', headers['Access-Control-Allow-Origin']
+  end
+
+  def test_options_without_request_method_header_is_treated_as_a_simple_request
+    configure_api(methods: %w[GET])
+    env = env_for('OPTIONS', '/api/posts', headers: {'Origin' => 'https://app.example.com'})
+    status, = @app.call(env)
+    assert_equal 200, status
+    assert_equal 1, @downstream_calls
+  end
+end