require "test_helper"

class WaysControllerTest < ActionController::TestCase
  ##
  # test all routes which lead to this controller
  def test_routes
    assert_routing(
      { :path => "/api/0.6/way/create", :method => :put },
      { :controller => "ways", :action => "create" }
    )
    assert_routing(
      { :path => "/api/0.6/way/1/full", :method => :get },
      { :controller => "ways", :action => "full", :id => "1" }
    )
    assert_routing(
      { :path => "/api/0.6/way/1", :method => :get },
      { :controller => "ways", :action => "show", :id => "1" }
    )
    assert_routing(
      { :path => "/api/0.6/way/1", :method => :put },
      { :controller => "ways", :action => "update", :id => "1" }
    )
    assert_routing(
      { :path => "/api/0.6/way/1", :method => :delete },
      { :controller => "ways", :action => "delete", :id => "1" }
    )
    assert_routing(
      { :path => "/api/0.6/ways", :method => :get },
      { :controller => "ways", :action => "index" }
    )
  end

  # -------------------------------------
  # Test showing ways.
  # -------------------------------------

  def test_show
    # check that a visible way is returned properly
    get :show, :params => { :id => create(:way).id }
    assert_response :success

    # check that an invisible way is not returned
    get :show, :params => { :id => create(:way, :deleted).id }
    assert_response :gone

    # check chat a non-existent way is not returned
    get :show, :params => { :id => 0 }
    assert_response :not_found
  end

  ##
  # check the "full" mode
  def test_full
    Way.all.each do |way|
      get :full, :params => { :id => way.id }

      # full call should say "gone" for non-visible ways...
      unless way.visible
        assert_response :gone
        next
      end

      # otherwise it should say success
      assert_response :success

      # Check the way is correctly returned
      assert_select "osm way[id='#{way.id}'][version='#{way.version}'][visible='#{way.visible}']", 1

      # check that each node in the way appears once in the output as a
      # reference and as the node element.
      way.nodes.each do |n|
        count = (way.nodes - (way.nodes - [n])).length
        assert_select "osm way nd[ref='#{n.id}']", count
        assert_select "osm node[id='#{n.id}'][version='#{n.version}'][lat='#{format('%.7f', n.lat)}'][lon='#{format('%.7f', n.lon)}']", 1
      end
    end
  end

  ##
  # test fetching multiple ways
  def test_index
    way1 = create(:way)
    way2 = create(:way, :deleted)
    way3 = create(:way)
    way4 = create(:way)

    # check error when no parameter provided
    get :index
    assert_response :bad_request

    # check error when no parameter value provided
    get :index, :params => { :ways => "" }
    assert_response :bad_request

    # test a working call
    get :index, :params => { :ways => "#{way1.id},#{way2.id},#{way3.id},#{way4.id}" }
    assert_response :success
    assert_select "osm" do
      assert_select "way", :count => 4
      assert_select "way[id='#{way1.id}'][visible='true']", :count => 1
      assert_select "way[id='#{way2.id}'][visible='false']", :count => 1
      assert_select "way[id='#{way3.id}'][visible='true']", :count => 1
      assert_select "way[id='#{way4.id}'][visible='true']", :count => 1
    end

    # check error when a non-existent way is included
    get :index, :params => { :ways => "#{way1.id},#{way2.id},#{way3.id},#{way4.id},0" }
    assert_response :not_found
  end

  # -------------------------------------
  # Test simple way creation.
  # -------------------------------------

  def test_create
    node1 = create(:node)
    node2 = create(:node)
    private_user = create(:user, :data_public => false)
    private_changeset = create(:changeset, :user => private_user)
    user = create(:user)
    changeset = create(:changeset, :user => user)

    ## First check that it fails when creating a way using a non-public user
    basic_authorization private_user.email, "test"

    # use the first user's open changeset
    changeset_id = private_changeset.id

    # create a way with pre-existing nodes
    xml = "<osm><way changeset='#{changeset_id}'>" \
          "<nd ref='#{node1.id}'/><nd ref='#{node2.id}'/>" \
          "<tag k='test' v='yes' /></way></osm>"
    put :create, :body => xml
    # hope for failure
    assert_response :forbidden,
                    "way upload did not return forbidden status"

    ## Now use a public user
    basic_authorization user.email, "test"

    # use the first user's open changeset
    changeset_id = changeset.id

    # create a way with pre-existing nodes
    xml = "<osm><way changeset='#{changeset_id}'>" \
          "<nd ref='#{node1.id}'/><nd ref='#{node2.id}'/>" \
          "<tag k='test' v='yes' /></way></osm>"
    put :create, :body => xml
    # hope for success
    assert_response :success,
                    "way upload did not return success status"
    # read id of created way and search for it
    wayid = @response.body
    checkway = Way.find(wayid)
    assert_not_nil checkway,
                   "uploaded way not found in data base after upload"
    # compare values
    assert_equal checkway.nds.length, 2,
                 "saved way does not contain exactly one node"
    assert_equal checkway.nds[0], node1.id,
                 "saved way does not contain the right node on pos 0"
    assert_equal checkway.nds[1], node2.id,
                 "saved way does not contain the right node on pos 1"
    assert_equal checkway.changeset_id, changeset_id,
                 "saved way does not belong to the correct changeset"
    assert_equal user.id, checkway.changeset.user_id,
                 "saved way does not belong to user that created it"
    assert_equal true, checkway.visible,
                 "saved way is not visible"
  end

  # -------------------------------------
  # Test creating some invalid ways.
  # -------------------------------------

  def test_create_invalid
    node = create(:node)
    private_user = create(:user, :data_public => false)
    private_open_changeset = create(:changeset, :user => private_user)
    private_closed_changeset = create(:changeset, :closed, :user => private_user)
    user = create(:user)
    open_changeset = create(:changeset, :user => user)
    closed_changeset = create(:changeset, :closed, :user => user)

    ## First test with a private user to make sure that they are not authorized
    basic_authorization private_user.email, "test"

    # use the first user's open changeset
    # create a way with non-existing node
    xml = "<osm><way changeset='#{private_open_changeset.id}'>" \
          "<nd ref='0'/><tag k='test' v='yes' /></way></osm>"
    put :create, :body => xml
    # expect failure
    assert_response :forbidden,
                    "way upload with invalid node using a private user did not return 'forbidden'"

    # create a way with no nodes
    xml = "<osm><way changeset='#{private_open_changeset.id}'>" \
          "<tag k='test' v='yes' /></way></osm>"
    put :create, :body => xml
    # expect failure
    assert_response :forbidden,
                    "way upload with no node using a private userdid not return 'forbidden'"

    # create a way inside a closed changeset
    xml = "<osm><way changeset='#{private_closed_changeset.id}'>" \
          "<nd ref='#{node.id}'/></way></osm>"
    put :create, :body => xml
    # expect failure
    assert_response :forbidden,
                    "way upload to closed changeset with a private user did not return 'forbidden'"

    ## Now test with a public user
    basic_authorization user.email, "test"

    # use the first user's open changeset
    # create a way with non-existing node
    xml = "<osm><way changeset='#{open_changeset.id}'>" \
          "<nd ref='0'/><tag k='test' v='yes' /></way></osm>"
    put :create, :body => xml
    # expect failure
    assert_response :precondition_failed,
                    "way upload with invalid node did not return 'precondition failed'"
    assert_equal "Precondition failed: Way  requires the nodes with id in (0), which either do not exist, or are not visible.", @response.body

    # create a way with no nodes
    xml = "<osm><way changeset='#{open_changeset.id}'>" \
          "<tag k='test' v='yes' /></way></osm>"
    put :create, :body => xml
    # expect failure
    assert_response :precondition_failed,
                    "way upload with no node did not return 'precondition failed'"
    assert_equal "Precondition failed: Cannot create way: data is invalid.", @response.body

    # create a way inside a closed changeset
    xml = "<osm><way changeset='#{closed_changeset.id}'>" \
          "<nd ref='#{node.id}'/></way></osm>"
    put :create, :body => xml
    # expect failure
    assert_response :conflict,
                    "way upload to closed changeset did not return 'conflict'"

    # create a way with a tag which is too long
    xml = "<osm><way changeset='#{open_changeset.id}'>" \
          "<nd ref='#{node.id}'/>" \
          "<tag k='foo' v='#{'x' * 256}'/>" \
          "</way></osm>"
    put :create, :body => xml
    # expect failure
    assert_response :bad_request,
                    "way upload to with too long tag did not return 'bad_request'"
  end

  # -------------------------------------
  # Test deleting ways.
  # -------------------------------------

  def test_delete
    private_user = create(:user, :data_public => false)
    private_open_changeset = create(:changeset, :user => private_user)
    private_closed_changeset = create(:changeset, :closed, :user => private_user)
    private_way = create(:way, :changeset => private_open_changeset)
    private_deleted_way = create(:way, :deleted, :changeset => private_open_changeset)
    private_used_way = create(:way, :changeset => private_open_changeset)
    create(:relation_member, :member => private_used_way)
    user = create(:user)
    open_changeset = create(:changeset, :user => user)
    closed_changeset = create(:changeset, :closed, :user => user)
    way = create(:way, :changeset => open_changeset)
    deleted_way = create(:way, :deleted, :changeset => open_changeset)
    used_way = create(:way, :changeset => open_changeset)
    relation_member = create(:relation_member, :member => used_way)
    relation = relation_member.relation

    # first try to delete way without auth
    delete :delete, :params => { :id => way.id }
    assert_response :unauthorized

    # now set auth using the private user
    basic_authorization private_user.email, "test"

    # this shouldn't work as with the 0.6 api we need pay load to delete
    delete :delete, :params => { :id => private_way.id }
    assert_response :forbidden

    # Now try without having a changeset
    xml = "<osm><way id='#{private_way.id}'/></osm>"
    delete :delete, :params => { :id => private_way.id }, :body => xml.to_s
    assert_response :forbidden

    # try to delete with an invalid (closed) changeset
    xml = update_changeset(private_way.to_xml, private_closed_changeset.id)
    delete :delete, :params => { :id => private_way.id }, :body => xml.to_s
    assert_response :forbidden

    # try to delete with an invalid (non-existent) changeset
    xml = update_changeset(private_way.to_xml, 0)
    delete :delete, :params => { :id => private_way.id }, :body => xml.to_s
    assert_response :forbidden

    # Now try with a valid changeset
    xml = private_way.to_xml
    delete :delete, :params => { :id => private_way.id }, :body => xml.to_s
    assert_response :forbidden

    # check the returned value - should be the new version number
    # valid delete should return the new version number, which should
    # be greater than the old version number
    # assert @response.body.to_i > current_ways(:visible_way).version,
    #   "delete request should return a new version number for way"

    # this won't work since the way is already deleted
    xml = private_deleted_way.to_xml
    delete :delete, :params => { :id => private_deleted_way.id }, :body => xml.to_s
    assert_response :forbidden

    # this shouldn't work as the way is used in a relation
    xml = private_used_way.to_xml
    delete :delete, :params => { :id => private_used_way.id }, :body => xml.to_s
    assert_response :forbidden,
                    "shouldn't be able to delete a way used in a relation (#{@response.body}), when done by a private user"

    # this won't work since the way never existed
    delete :delete, :params => { :id => 0 }
    assert_response :forbidden

    ### Now check with a public user
    # now set auth
    basic_authorization user.email, "test"

    # this shouldn't work as with the 0.6 api we need pay load to delete
    delete :delete, :params => { :id => way.id }
    assert_response :bad_request

    # Now try without having a changeset
    xml = "<osm><way id='#{way.id}'/></osm>"
    delete :delete, :params => { :id => way.id }, :body => xml.to_s
    assert_response :bad_request

    # try to delete with an invalid (closed) changeset
    xml = update_changeset(way.to_xml, closed_changeset.id)
    delete :delete, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict

    # try to delete with an invalid (non-existent) changeset
    xml = update_changeset(way.to_xml, 0)
    delete :delete, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict

    # Now try with a valid changeset
    xml = way.to_xml
    delete :delete, :params => { :id => way.id }, :body => xml.to_s
    assert_response :success

    # check the returned value - should be the new version number
    # valid delete should return the new version number, which should
    # be greater than the old version number
    assert @response.body.to_i > way.version,
           "delete request should return a new version number for way"

    # this won't work since the way is already deleted
    xml = deleted_way.to_xml
    delete :delete, :params => { :id => deleted_way.id }, :body => xml.to_s
    assert_response :gone

    # this shouldn't work as the way is used in a relation
    xml = used_way.to_xml
    delete :delete, :params => { :id => used_way.id }, :body => xml.to_s
    assert_response :precondition_failed,
                    "shouldn't be able to delete a way used in a relation (#{@response.body})"
    assert_equal "Precondition failed: Way #{used_way.id} is still used by relations #{relation.id}.", @response.body

    # this won't work since the way never existed
    delete :delete, :params => { :id => 0 }
    assert_response :not_found
  end

  ##
  # tests whether the API works and prevents incorrect use while trying
  # to update ways.
  def test_update
    private_user = create(:user, :data_public => false)
    private_way = create(:way, :changeset => create(:changeset, :user => private_user))
    user = create(:user)
    way = create(:way, :changeset => create(:changeset, :user => user))
    node = create(:node)
    create(:way_node, :way => private_way, :node => node)
    create(:way_node, :way => way, :node => node)

    ## First test with no user credentials
    # try and update a way without authorisation
    xml = way.to_xml
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :unauthorized

    ## Second test with the private user

    # setup auth
    basic_authorization private_user.email, "test"

    ## trying to break changesets

    # try and update in someone else's changeset
    xml = update_changeset(private_way.to_xml,
                           create(:changeset).id)
    put :update, :params => { :id => private_way.id }, :body => xml.to_s
    assert_require_public_data "update with other user's changeset should be forbidden when date isn't public"

    # try and update in a closed changeset
    xml = update_changeset(private_way.to_xml,
                           create(:changeset, :closed, :user => private_user).id)
    put :update, :params => { :id => private_way.id }, :body => xml.to_s
    assert_require_public_data "update with closed changeset should be forbidden, when data isn't public"

    # try and update in a non-existant changeset
    xml = update_changeset(private_way.to_xml, 0)
    put :update, :params => { :id => private_way.id }, :body => xml.to_s
    assert_require_public_data("update with changeset=0 should be forbidden, when data isn't public")

    ## try and submit invalid updates
    xml = xml_replace_node(private_way.to_xml, node.id, 9999)
    put :update, :params => { :id => private_way.id }, :body => xml.to_s
    assert_require_public_data "way with non-existent node should be forbidden, when data isn't public"

    xml = xml_replace_node(private_way.to_xml, node.id, create(:node, :deleted).id)
    put :update, :params => { :id => private_way.id }, :body => xml.to_s
    assert_require_public_data "way with deleted node should be forbidden, when data isn't public"

    ## finally, produce a good request which will still not work
    xml = private_way.to_xml
    put :update, :params => { :id => private_way.id }, :body => xml.to_s
    assert_require_public_data "should have failed with a forbidden when data isn't public"

    ## Finally test with the public user

    # setup auth
    basic_authorization user.email, "test"

    ## trying to break changesets

    # try and update in someone else's changeset
    xml = update_changeset(way.to_xml,
                           create(:changeset).id)
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict, "update with other user's changeset should be rejected"

    # try and update in a closed changeset
    xml = update_changeset(way.to_xml,
                           create(:changeset, :closed, :user => user).id)
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict, "update with closed changeset should be rejected"

    # try and update in a non-existant changeset
    xml = update_changeset(way.to_xml, 0)
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict, "update with changeset=0 should be rejected"

    ## try and submit invalid updates
    xml = xml_replace_node(way.to_xml, node.id, 9999)
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :precondition_failed, "way with non-existent node should be rejected"

    xml = xml_replace_node(way.to_xml, node.id, create(:node, :deleted).id)
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :precondition_failed, "way with deleted node should be rejected"

    ## next, attack the versioning
    current_way_version = way.version

    # try and submit a version behind
    xml = xml_attr_rewrite(way.to_xml,
                           "version", current_way_version - 1)
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict, "should have failed on old version number"

    # try and submit a version ahead
    xml = xml_attr_rewrite(way.to_xml,
                           "version", current_way_version + 1)
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict, "should have failed on skipped version number"

    # try and submit total crap in the version field
    xml = xml_attr_rewrite(way.to_xml,
                           "version", "p1r4t3s!")
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :conflict,
                    "should not be able to put 'p1r4at3s!' in the version field"

    ## try an update with the wrong ID
    xml = create(:way).to_xml
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :bad_request,
                    "should not be able to update a way with a different ID from the XML"

    ## try an update with a minimal valid XML doc which isn't a well-formed OSM doc.
    xml = "<update/>"
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :bad_request,
                    "should not be able to update a way with non-OSM XML doc."

    ## finally, produce a good request which should work
    xml = way.to_xml
    put :update, :params => { :id => way.id }, :body => xml.to_s
    assert_response :success, "a valid update request failed"
  end

  # ------------------------------------------------------------
  # test tags handling
  # ------------------------------------------------------------

  ##
  # Try adding a new tag to a way
  def test_add_tags
    private_user = create(:user, :data_public => false)
    private_way = create(:way_with_nodes, :nodes_count => 2, :changeset => create(:changeset, :user => private_user))
    user = create(:user)
    way = create(:way_with_nodes, :nodes_count => 2, :changeset => create(:changeset, :user => user))

    ## Try with the non-public user
    # setup auth
    basic_authorization private_user.email, "test"

    # add an identical tag to the way
    tag_xml = XML::Node.new("tag")
    tag_xml["k"] = "new"
    tag_xml["v"] = "yes"

    # add the tag into the existing xml
    way_xml = private_way.to_xml
    way_xml.find("//osm/way").first << tag_xml

    # try and upload it
    put :update, :params => { :id => private_way.id }, :body => way_xml.to_s
    assert_response :forbidden,
                    "adding a duplicate tag to a way for a non-public should fail with 'forbidden'"

    ## Now try with the public user
    # setup auth
    basic_authorization user.email, "test"

    # add an identical tag to the way
    tag_xml = XML::Node.new("tag")
    tag_xml["k"] = "new"
    tag_xml["v"] = "yes"

    # add the tag into the existing xml
    way_xml = way.to_xml
    way_xml.find("//osm/way").first << tag_xml

    # try and upload it
    put :update, :params => { :id => way.id }, :body => way_xml.to_s
    assert_response :success,
                    "adding a new tag to a way should succeed"
    assert_equal way.version + 1, @response.body.to_i
  end

  ##
  # Try adding a duplicate of an existing tag to a way
  def test_add_duplicate_tags
    private_user = create(:user, :data_public => false)
    private_way = create(:way, :changeset => create(:changeset, :user => private_user))
    private_existing_tag = create(:way_tag, :way => private_way)
    user = create(:user)
    way = create(:way, :changeset => create(:changeset, :user => user))
    existing_tag = create(:way_tag, :way => way)

    ## Try with the non-public user
    # setup auth
    basic_authorization private_user.email, "test"

    # add an identical tag to the way
    tag_xml = XML::Node.new("tag")
    tag_xml["k"] = private_existing_tag.k
    tag_xml["v"] = private_existing_tag.v

    # add the tag into the existing xml
    way_xml = private_way.to_xml
    way_xml.find("//osm/way").first << tag_xml

    # try and upload it
    put :update, :params => { :id => private_way.id }, :body => way_xml.to_s
    assert_response :forbidden,
                    "adding a duplicate tag to a way for a non-public should fail with 'forbidden'"

    ## Now try with the public user
    # setup auth
    basic_authorization user.email, "test"

    # add an identical tag to the way
    tag_xml = XML::Node.new("tag")
    tag_xml["k"] = existing_tag.k
    tag_xml["v"] = existing_tag.v

    # add the tag into the existing xml
    way_xml = way.to_xml
    way_xml.find("//osm/way").first << tag_xml

    # try and upload it
    put :update, :params => { :id => way.id }, :body => way_xml.to_s
    assert_response :bad_request,
                    "adding a duplicate tag to a way should fail with 'bad request'"
    assert_equal "Element way/#{way.id} has duplicate tags with key #{existing_tag.k}", @response.body
  end

  ##
  # Try adding a new duplicate tags to a way
  def test_new_duplicate_tags
    private_user = create(:user, :data_public => false)
    private_way = create(:way, :changeset => create(:changeset, :user => private_user))
    user = create(:user)
    way = create(:way, :changeset => create(:changeset, :user => user))

    ## First test with the non-public user so should be rejected
    # setup auth
    basic_authorization private_user.email, "test"

    # create duplicate tag
    tag_xml = XML::Node.new("tag")
    tag_xml["k"] = "i_am_a_duplicate"
    tag_xml["v"] = "foobar"

    # add the tag into the existing xml
    way_xml = private_way.to_xml

    # add two copies of the tag
    way_xml.find("//osm/way").first << tag_xml.copy(true) << tag_xml

    # try and upload it
    put :update, :params => { :id => private_way.id }, :body => way_xml.to_s
    assert_response :forbidden,
                    "adding new duplicate tags to a way using a non-public user should fail with 'forbidden'"

    ## Now test with the public user
    # setup auth
    basic_authorization user.email, "test"

    # create duplicate tag
    tag_xml = XML::Node.new("tag")
    tag_xml["k"] = "i_am_a_duplicate"
    tag_xml["v"] = "foobar"

    # add the tag into the existing xml
    way_xml = way.to_xml

    # add two copies of the tag
    way_xml.find("//osm/way").first << tag_xml.copy(true) << tag_xml

    # try and upload it
    put :update, :params => { :id => way.id }, :body => way_xml.to_s
    assert_response :bad_request,
                    "adding new duplicate tags to a way should fail with 'bad request'"
    assert_equal "Element way/#{way.id} has duplicate tags with key i_am_a_duplicate", @response.body
  end

  ##
  # Try adding a new duplicate tags to a way.
  # But be a bit subtle - use unicode decoding ambiguities to use different
  # binary strings which have the same decoding.
  def test_invalid_duplicate_tags
    private_user = create(:user, :data_public => false)
    private_changeset = create(:changeset, :user => private_user)
    user = create(:user)
    changeset = create(:changeset, :user => user)

    ## First make sure that you can't with a non-public user
    # setup auth
    basic_authorization private_user.email, "test"

    # add the tag into the existing xml
    way_str = "<osm><way changeset='#{private_changeset.id}'>"
    way_str << "<tag k='addr:housenumber' v='1'/>"
    way_str << "<tag k='addr:housenumber' v='2'/>"
    way_str << "</way></osm>"

    # try and upload it
    put :create, :body => way_str
    assert_response :forbidden,
                    "adding new duplicate tags to a way with a non-public user should fail with 'forbidden'"

    ## Now do it with a public user
    # setup auth
    basic_authorization user.email, "test"

    # add the tag into the existing xml
    way_str = "<osm><way changeset='#{changeset.id}'>"
    way_str << "<tag k='addr:housenumber' v='1'/>"
    way_str << "<tag k='addr:housenumber' v='2'/>"
    way_str << "</way></osm>"

    # try and upload it
    put :create, :body => way_str
    assert_response :bad_request,
                    "adding new duplicate tags to a way should fail with 'bad request'"
    assert_equal "Element way/ has duplicate tags with key addr:housenumber", @response.body
  end

  ##
  # test that a call to ways_for_node returns all ways that contain the node
  # and none that don't.
  def test_ways_for_node
    node = create(:node)
    way1 = create(:way)
    way2 = create(:way)
    create(:way_node, :way => way1, :node => node)
    create(:way_node, :way => way2, :node => node)
    # create an unrelated way
    create(:way_with_nodes, :nodes_count => 2)
    # create a way which used to use the node
    way3_v1 = create(:old_way, :version => 1)
    _way3_v2 = create(:old_way, :current_way => way3_v1.current_way, :version => 2)
    create(:old_way_node, :old_way => way3_v1, :node => node)

    get :ways_for_node, :params => { :id => node.id }
    assert_response :success
    ways_xml = XML::Parser.string(@response.body).parse
    assert_not_nil ways_xml, "failed to parse ways_for_node response"

    # check that the set of IDs match expectations
    expected_way_ids = [way1.id,
                        way2.id]
    found_way_ids = ways_xml.find("//osm/way").collect { |w| w["id"].to_i }
    assert_equal expected_way_ids.sort, found_way_ids.sort,
                 "expected ways for node #{node.id} did not match found"

    # check the full ways to ensure we're not missing anything
    expected_way_ids.each do |id|
      way_xml = ways_xml.find("//osm/way[@id='#{id}']").first
      assert_ways_are_equal(Way.find(id),
                            Way.from_xml_node(way_xml))
    end
  end

  ##
  # update the changeset_id of a way element
  def update_changeset(xml, changeset_id)
    xml_attr_rewrite(xml, "changeset", changeset_id)
  end

  ##
  # update an attribute in the way element
  def xml_attr_rewrite(xml, name, value)
    xml.find("//osm/way").first[name] = value.to_s
    xml
  end

  ##
  # replace a node in a way element
  def xml_replace_node(xml, old_node, new_node)
    xml.find("//osm/way/nd[@ref='#{old_node}']").first["ref"] = new_node.to_s
    xml
  end
end