test: cover ArticlePagesController and show

test/test_conditional_get.rb

@@ -0,0 +1,140 @@
+require 'minitest/autorun'
+require 'prism'
+require 'support'
+
+class ArticlePagesController < Prism::Controller
+  CURRENT_ETAG = 'article-42-v3'
+  CURRENT_MODIFIED = Time.utc(2026, 1, 1, 12, 0, 0)
+
+  def show
+    fresh_when(etag: CURRENT_ETAG, last_modified: CURRENT_MODIFIED)
+    html('full article body')
+  end
+
+  def show_strong
+    fresh_when(etag: CURRENT_ETAG, weak: false)
+    html('full article body')
+  end
+
+  def edit
+    if stale?(etag: CURRENT_ETAG)
+      html('editable article body')
+    else
+      raise 'should not reach render when not stale'
+    end
+  end
+
+  def update
+    fresh_when(etag: CURRENT_ETAG, last_modified: CURRENT_MODIFIED)
+    html('updated')
+  end
+end
+
+class ConditionalGetApp < Prism::Application
+  get '/article', to: 'article_pages#show'
+  get '/article/strong', to: 'article_pages#show_strong'
+  get '/article/edit', to: 'article_pages#edit'
+  patch '/article', to: 'article_pages#update'
+end
+
+class ConditionalGetTest < Minitest::Test
+  include TestSupport
+
+  def call(method, path, **opts)
+    ConditionalGetApp.call(env_for(method, path, **opts))
+  end
+
+  def test_first_request_renders_and_sets_etag_and_last_modified
+    status, headers, body = call('GET', '/article')
+    assert_equal 200, status
+    assert_equal 'full article body', body.join
+    refute_nil headers['ETag']
+    assert_equal 'W/"' + Digest::SHA1.hexdigest('article-42-v3') + '"', headers['ETag']
+    assert_equal ArticlePagesController::CURRENT_MODIFIED.httpdate, headers['Last-Modified']
+  end
+
+  def test_matching_if_none_match_returns_304_with_empty_body
+    etag = 'W/"' + Digest::SHA1.hexdigest('article-42-v3') + '"'
+    status, _, body = call('GET', '/article', headers: { 'If-None-Match' => etag })
+    assert_equal 304, status
+    assert_equal '', body.join
+  end
+
+  def test_stale_if_none_match_still_renders_with_200
+    status, _, body = call('GET', '/article', headers: { 'If-None-Match' => 'W/"stale-value"' })
+    assert_equal 200, status
+    assert_equal 'full article body', body.join
+  end
+
+  def test_wildcard_if_none_match_is_always_fresh
+    status, = call('GET', '/article', headers: { 'If-None-Match' => '*' })
+    assert_equal 304, status
+  end
+
+  def test_if_modified_since_after_last_modified_is_fresh
+    status, = call('GET', '/article', headers: { 'If-Modified-Since' => (ArticlePagesController::CURRENT_MODIFIED + 3600).httpdate })
+    assert_equal 304, status
+  end
+
+  def test_if_modified_since_before_last_modified_is_stale
+    status, _, body = call('GET', '/article', headers: { 'If-Modified-Since' => (ArticlePagesController::CURRENT_MODIFIED - 3600).httpdate })
+    assert_equal 200, status
+    assert_equal 'full article body', body.join
+  end
+
+  def test_strong_etag_has_no_weak_prefix
+    status, headers, = call('GET', '/article/strong')
+    assert_equal 200, status
+    assert_equal '"' + Digest::SHA1.hexdigest('article-42-v3') + '"', headers['ETag']
+  end
+
+  def test_stale_predicate_renders_when_no_conditional_headers_sent
+    status, _, body = call('GET', '/article/edit')
+    assert_equal 200, status
+    assert_equal 'editable article body', body.join
+  end
+
+  def test_stale_predicate_halts_with_304_and_skips_render_when_fresh
+    etag = 'W/"' + Digest::SHA1.hexdigest('article-42-v3') + '"'
+    status, _, body = call('GET', '/article/edit', headers: { 'If-None-Match' => etag })
+    assert_equal 304, status
+    assert_equal '', body.join
+  end
+
+  def test_matching_if_match_lets_the_write_through
+    etag = 'W/"' + Digest::SHA1.hexdigest('article-42-v3') + '"'
+    status, _, body = call('PATCH', '/article', headers: { 'If-Match' => etag })
+    assert_equal 200, status
+    assert_equal 'updated', body.join
+  end
+
+  def test_stale_if_match_returns_412_and_skips_the_write
+    status, _, body = call('PATCH', '/article', headers: { 'If-Match' => 'W/"someone-elses-version"' })
+    assert_equal 412, status
+    assert_equal '', body.join
+  end
+
+  def test_wildcard_if_match_always_passes_the_precondition
+    status, = call('PATCH', '/article', headers: { 'If-Match' => '*' })
+    assert_equal 200, status
+  end
+
+  def test_if_unmodified_since_before_last_modified_returns_412
+    header = (ArticlePagesController::CURRENT_MODIFIED - 3600).httpdate
+    status, _, body = call('PATCH', '/article', headers: { 'If-Unmodified-Since' => header })
+    assert_equal 412, status
+    assert_equal '', body.join
+  end
+
+  def test_if_unmodified_since_at_or_after_last_modified_lets_the_write_through
+    header = ArticlePagesController::CURRENT_MODIFIED.httpdate
+    status, _, body = call('PATCH', '/article', headers: { 'If-Unmodified-Since' => header })
+    assert_equal 200, status
+    assert_equal 'updated', body.join
+  end
+
+  def test_no_precondition_headers_lets_the_write_through
+    status, = call('PATCH', '/article')
+    assert_equal 200, status
+  end
+end