test: add test harness with http and router tests

test/test_response.rb

@@ -0,0 +1,32 @@
+require 'minitest/autorun'
+require 'prism'
+
+class ResponseTest < Minitest::Test
+  def test_defaults
+    status, headers, body = Prism::Response.new.finish
+    assert_equal 200, status
+    assert_equal 'text/html;charset=utf-8', headers['Content-Type']
+    assert_equal [], body
+  end
+
+  def test_write
+    response = Prism::Response.new
+    response << 'a'
+    response.write('b')
+    assert_equal %w[a b], response.finish[2]
+  end
+
+  def test_set_cookie
+    response = Prism::Response.new
+    response.set_cookie('token', 'abc def')
+    assert_includes response.headers['Set-Cookie'], 'token=abc+def'
+    assert_includes response.headers['Set-Cookie'], 'HttpOnly'
+  end
+
+  def test_multiple_cookies
+    response = Prism::Response.new
+    response.set_cookie('a', '1')
+    response.set_cookie('b', '2')
+    assert_equal 2, response.headers['Set-Cookie'].split("\n").size
+  end
+end