test: add template, view, session, and flash tests

test/test_session.rb

@@ -0,0 +1,33 @@
+require 'minitest/autorun'
+require 'prism'
+
+class SessionTest < Minitest::Test
+  def test_roundtrip
+    cookie = Prism::Session.encode({ 'user' => 'foksiu', 'count' => 3 }, 'top-secret')
+    decoded = Prism::Session.decode(cookie, 'top-secret')
+    assert_equal 'foksiu', decoded['user']
+    assert_equal 3, decoded['count']
+  end
+
+  def test_tampering_rejected
+    cookie = Prism::Session.encode({ 'admin' => false }, 'top-secret')
+    payload, signature = cookie.split('--', 2)
+    forged = "#{payload}--#{'0' * signature.size}"
+    assert_equal({}, Prism::Session.decode(forged, 'top-secret'))
+  end
+
+  def test_wrong_secret
+    cookie = Prism::Session.encode({ 'x' => 1 }, 'secret-a')
+    assert_equal({}, Prism::Session.decode(cookie, 'secret-b'))
+  end
+
+  def test_cookie_is_url_safe
+    cookie = Prism::Session.encode({ 'blob' => 'a' * 60 }, 's')
+    assert_nil cookie[/[^A-Za-z0-9_\-]/], "expected url safe cookie, got: #{cookie}"
+  end
+
+  def test_missing_cookie
+    assert_equal({}, Prism::Session.decode(nil, 's'))
+    assert_equal({}, Prism::Session.decode('', 's'))
+  end
+end