test: add spec to compare servlet env vs default env parsing of some edge cases

Author: chadlwilson

src/spec/ruby/rack/handler/servlet_env_parsing_spec.rb

@@ -0,0 +1,90 @@
+#--
+# This source code is available under the MIT license.
+# See the file LICENSE.txt for details.
+#++
+
+require File.expand_path('../../spec_helper', File.dirname(__FILE__))
+
+require 'rack'
+require 'rack/handler/servlet'
+
+# Differential coverage: the "pure" ServletEnv maps servlet-parsed parameters
+# (HttpServletRequest#getParameterMap) into the Rack env, whereas DefaultEnv
+# lets Rack itself parse the QUERY_STRING. ServletEnv's whole reason to exist
+# is to produce the *same* params Rack would - so here we drive the same query
+# string through both and assert Rack::Request#GET comes out identical.
+#
+# The decoded values handed to addParameter are written as literals (simulating
+# what a servlet container decodes getParameterMap to), NOT computed via Rack's
+# unescaper - otherwise the escaping comparison would be circular.
+describe 'Rack::Handler::Servlet ServletEnv vs DefaultEnv (parsing parity)' do
+
+  before do
+    @servlet_context = mock_servlet_context
+  end
+
+  # Build Rack::Request#GET from a query string using the given env class.
+  # +params+ are the (already url-decoded) name/value pairs the servlet
+  # container would expose via getParameterMap; DefaultEnv ignores them.
+  def get_params(env_class, query_string, params = [])
+    request = org.springframework.mock.web.MockHttpServletRequest.new(@servlet_context)
+    request.setMethod('GET')
+    request.setRequestURI('/path')
+    request.setQueryString(query_string)
+    params.each { |name, value| request.addParameter(name, value) }
+    response = org.springframework.mock.web.MockHttpServletResponse.new
+    servlet_env = org.jruby.rack.servlet.ServletRackEnvironment.new(request, response, @rack_context)
+    Rack::Request.new(env_class.create(servlet_env)).GET
+  end
+
+  DefaultEnv = Rack::Handler::Servlet::DefaultEnv
+  ServletEnv = Rack::Handler::Servlet::ServletEnv
+
+  # [ description, query_string, decoded getParameterMap pairs ]
+  PARITY_CASES = [
+    [ 'plain params',            'a=1&b=2',                 [ %w(a 1), %w(b 2) ] ],
+    [ 'space via +',             'a=x+y',                   [ [ 'a', 'x y' ] ] ],
+    [ 'space via %20',           'a=x%20y',                 [ [ 'a', 'x y' ] ] ],
+    [ 'encoded & = #',           'a=%26%3D%23',             [ [ 'a', '&=#' ] ] ],
+    [ 'encoded = in value',      'a=b%3Dc',                 [ [ 'a', 'b=c' ] ] ],
+    [ 'utf-8 name and value',    'caf%C3%A9=%C3%BC',        [ [ "café", "ü" ] ] ],
+    [ 'repeated flat key',       'a=1&a=2',                 [ %w(a 1), %w(a 2) ] ],
+    [ 'array [] key',            'a%5B%5D=1&a%5B%5D=2',     [ [ 'a[]', '1' ], [ 'a[]', '2' ] ] ],
+    [ 'hash [k] key',            'a%5Bb%5D=1',              [ [ 'a[b]', '1' ] ] ],
+    [ 'empty value',             'a=',                      [ [ 'a', '' ] ] ],
+  ]
+
+  PARITY_CASES.each do |desc, query_string, params|
+    it "matches DefaultEnv (real Rack) for #{desc}" do
+      default_get = get_params(DefaultEnv, query_string)
+      servlet_get = get_params(ServletEnv, query_string, params)
+      expect(servlet_get).to eq(default_get)
+    end
+  end
+
+  # Known divergences of the hand-rolled ServletEnv#store_parameter from Rack's
+  # own nested-query parsing. Documented here so the gap is explicit (and any
+  # future change to store_parameter can turn these into parity cases).
+  describe 'known divergences from Rack' do
+
+    it 'hash-in-array (a[][b]) is not parsed the same as Rack' do
+      query_string = 'a%5B%5D%5Bb%5D=1'
+      default_get = get_params(DefaultEnv, query_string)                 # Rack: {"a"=>[{"b"=>"1"}]}
+      servlet_get = get_params(ServletEnv, query_string, [ [ 'a[][b]', '1' ] ])
+
+      expect(default_get).to eq({ 'a' => [ { 'b' => '1' } ] })
+      expect(servlet_get).to_not eq(default_get) # documents the current gap
+    end
+
+    it 'deep nesting (a[b][c]) is only nested one level by store_parameter' do
+      query_string = 'a%5Bb%5D%5Bc%5D=x'
+      default_get = get_params(DefaultEnv, query_string)                 # Rack: {"a"=>{"b"=>{"c"=>"x"}}}
+      servlet_get = get_params(ServletEnv, query_string, [ [ 'a[b][c]', 'x' ] ])
+
+      expect(default_get).to eq({ 'a' => { 'b' => { 'c' => 'x' } } })
+      expect(servlet_get).to eq({ 'a' => { 'b][c' => 'x' } }) # current (broken) behavior
+    end
+
+  end
+
+end