diff --git a/.github/workflows/main.yml b/.github/workflows/rspec.yml
similarity index 75%
rename from .github/workflows/main.yml
rename to .github/workflows/rspec.yml
index cca9825..73b2539 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/rspec.yml
@@ -1,4 +1,4 @@
-name: Ruby
+name: RSpec
 
 on: [push, pull_request]
 
@@ -6,6 +6,15 @@ jobs:
   build:
     runs-on: ubuntu-latest
 
+    services:
+      radicale:
+        image: xlrl/radicale
+        ports:
+        - 8000:8000
+        env:
+          RADICALE_USER: test
+          RADICALE_PASS: test
+
     strategy:
       fail-fast: false
       matrix:
@@ -17,18 +26,12 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
-    - name: Run Radicale
-      run: docker run -v ${{ github.workspace }}/spec/data/radicale:/var/radicale --name radicale --publish 8000:8000 --detach xlrl/radicale
-
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true
 
-    - name: Rubocop
-      run: bundle exec rubocop
-
     - name: RSpec
       env:
         APPLE_USERNAME: ${{ secrets.APPLE_USERNAME }}
@@ -41,6 +44,3 @@ jobs:
         RADICALE_PASSWORD: test
         RADICALE_HOST: http://127.0.0.1:8000
       run: bundle exec rspec
-
-    - name: Stop Radicale
-      run: docker stop radicale
diff --git a/.github/workflows/rubocop.yml b/.github/workflows/rubocop.yml
new file mode 100644
index 0000000..ebfd91f
--- /dev/null
+++ b/.github/workflows/rubocop.yml
@@ -0,0 +1,19 @@
+name: Rubocop
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: 3.1
+        bundler-cache: true
+
+    - name: Rubocop
+      run: bundle exec rubocop
diff --git a/calendav.gemspec b/calendav.gemspec
index 633af0a..b80d53f 100644
--- a/calendav.gemspec
+++ b/calendav.gemspec
@@ -24,10 +24,11 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_runtime_dependency "http"
-  spec.add_runtime_dependency "icalendar"
-  spec.add_runtime_dependency "nokogiri"
+  spec.add_dependency "http"
+  spec.add_dependency "icalendar"
+  spec.add_dependency "nokogiri"
 
+  spec.add_development_dependency "debug"
   spec.add_development_dependency "dotenv"
   spec.add_development_dependency "google-api-client"
   spec.add_development_dependency "googleauth"
diff --git a/lib/calendav/clients/calendars_client.rb b/lib/calendav/clients/calendars_client.rb
index 33d7a18..6eba64c 100644
--- a/lib/calendav/clients/calendars_client.rb
+++ b/lib/calendav/clients/calendars_client.rb
@@ -1,14 +1,17 @@
 # frozen_string_literal: true
 
 require "securerandom"
+require "icalendar"
 
 require_relative "../calendar"
+require_relative "../components/freebusy"
 require_relative "../parsers/sync_xml"
 require_relative "../requests/calendar_home_set"
 require_relative "../requests/list_calendars"
 require_relative "../requests/make_calendar"
 require_relative "../requests/sync_collection"
 require_relative "../requests/update_calendar"
+require_relative "../requests/free_busy_query"
 
 module Calendav
   module Clients
@@ -59,7 +62,8 @@ def find(url, attributes: DEFAULT_ATTRIBUTES, sync: false)
 
       def list(url = home_url, depth: 1, attributes: DEFAULT_ATTRIBUTES)
         request = Requests::ListCalendars.call(attributes)
-        calendar_xpath = ".//dav:resourcetype/caldav:calendar"
+        calendar_xpath =
+          "//d:response[d:propstat/d:prop/cal:supported-calendar-component-set]"
 
         endpoint
           .propfind(request.to_xml, url: url, depth: depth)
@@ -91,6 +95,12 @@ def update(url, attributes)
           .text["200 OK"] == "200 OK"
       end
 
+      def freebusy(url, from:, to:)
+        request = Requests::FreeBusyQuery.call(from: from, to: to)
+        response = endpoint.report(request.to_xml, url: url, depth: 1)
+        Components::Freebusy.from_http_response(response)
+      end
+
       private
 
       attr_reader :client, :endpoint, :credentials
diff --git a/lib/calendav/clients/events_client.rb b/lib/calendav/clients/events_client.rb
index 8467ff0..d573faf 100644
--- a/lib/calendav/clients/events_client.rb
+++ b/lib/calendav/clients/events_client.rb
@@ -39,8 +39,8 @@ def find(event_url)
         )
       end
 
-      def list(calendar_url, from: nil, to: nil)
-        request = Requests::ListEvents.call(from: from, to: to)
+      def list(calendar_url, from: nil, to: nil, expand: false)
+        request = Requests::ListEvents.call(from: from, to: to, expand: expand)
 
         endpoint
           .report(request.to_xml, url: calendar_url, depth: 1)
diff --git a/lib/calendav/components/freebusy.rb b/lib/calendav/components/freebusy.rb
new file mode 100644
index 0000000..eb5317f
--- /dev/null
+++ b/lib/calendav/components/freebusy.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require_relative "../properties/freebusy"
+
+module Calendav
+  module Components
+    class Freebusy
+      attr_reader :dtend, :dtstart, :dtstamp, :freebusy, :ical_name, :name,
+                  :parent, :uid
+
+      def self.from_http_response(response)
+        ical_freebusy = Icalendar::Freebusy.parse(response).first
+
+        attributes = attributes_from_ical_freebusy(ical_freebusy)
+        new(attributes)
+      end
+
+      def initialize(attributes)
+        @dtend = attributes[:dtend].to_time
+        @dtstart = attributes[:dtstart].to_time
+        @dtstamp = attributes[:dtstamp].to_time
+        @freebusy = attributes[:freebusy].map do |fb|
+          Properties::Freebusy.from_ical_period(fb)
+        end
+        @ical_name = attributes[:ical_name]
+        @name = attributes[:name]
+        @uid = attributes[:uid]
+      end
+
+      def to_h
+        {
+          dtend: dtend,
+          dtstart: dtstart,
+          dtstamp: dtstamp,
+          freebusy: freebusy,
+          ical_name: ical_name,
+          name: name,
+          parent: parent,
+          uid: uid
+        }
+      end
+
+      class << self
+        private
+
+        def attributes_from_ical_freebusy(ical_freebusy)
+          {
+            dtend: ical_freebusy.dtend,
+            dtstamp: ical_freebusy.dtstamp,
+            dtstart: ical_freebusy.dtstart,
+            freebusy: ical_freebusy.freebusy,
+            ical_name: ical_freebusy.ical_name,
+            name: ical_freebusy.name,
+            uid: ical_freebusy.uid
+          }
+        end
+      end
+    end
+  end
+end
diff --git a/lib/calendav/errors.rb b/lib/calendav/errors.rb
index 5dd1c67..379e31c 100644
--- a/lib/calendav/errors.rb
+++ b/lib/calendav/errors.rb
@@ -7,7 +7,7 @@ class ParsingXMLError < Error
     attr_reader :xml, :original
 
     def initialize(xml, original)
-      super original.message
+      super(original.message)
 
       @xml = xml
       @original = original
@@ -18,7 +18,7 @@ class RequestError < Error
     attr_reader :response
 
     def initialize(response)
-      super response.status.to_s
+      super(response.status.to_s)
 
       @response = response
     end
diff --git a/lib/calendav/properties/freebusy.rb b/lib/calendav/properties/freebusy.rb
new file mode 100644
index 0000000..b64fd80
--- /dev/null
+++ b/lib/calendav/properties/freebusy.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module Calendav
+  module Properties
+    class Freebusy
+      attr_reader :start_time, :end_time
+
+      def self.from_ical_period(period)
+        new(start_time: period.first.to_time, end_time: period.last.to_time)
+      end
+
+      def initialize(start_time:, end_time:)
+        validate_arguments(start_time, end_time)
+
+        @start_time = if start_time.respond_to?(:to_time)
+                        start_time.to_time
+                      else
+                        start_time
+                      end
+        @end_time = end_time.respond_to?(:to_time) ? end_time.to_time : end_time
+      end
+
+      def to_h
+        {
+          start_time: start_time,
+          end_time: end_time
+        }
+      end
+
+      def to_range
+        Range.new(start_time, end_time)
+      end
+
+      def duration
+        end_time - start_time
+      end
+
+      private
+
+      def validate_arguments(start_time, end_time)
+        return if (start_time.is_a?(Time) || start_time.respond_to?(:to_time)) &&
+                  (end_time.is_a?(Time) || end_time.respond_to?(:to_time))
+
+        raise ArgumentError,
+              "arguments must be instances of Time or respond to to_time"
+      end
+    end
+  end
+end
diff --git a/lib/calendav/requests/free_busy_query.rb b/lib/calendav/requests/free_busy_query.rb
new file mode 100644
index 0000000..92088fa
--- /dev/null
+++ b/lib/calendav/requests/free_busy_query.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "nokogiri"
+
+module Calendav
+  module Requests
+    class FreeBusyQuery
+      def self.call(...)
+        new(...).call
+      end
+
+      # @param from [Time, DateTime, String YYYYMMDDTHHMMSSZ (ISO8601 w/o dashes/colons)]
+      # @param to [Time, DateTime, String YYYYMMDDTHHMMSSZ (ISO8601 w/o dashes/colons)]
+      def initialize(from:, to:)
+        @from = time_to_formatted_string(from)
+        @to = time_to_formatted_string(to)
+      end
+
+      def call
+        Nokogiri::XML::Builder.new do |xml|
+          xml["c"].public_send(:"free-busy-query",
+                               "xmlns:c" => "urn:ietf:params:xml:ns:caldav") do
+            xml["c"].public_send(:"time-range", start: @from, end: @to)
+          end
+        end
+      end
+
+      private
+
+      def time_to_formatted_string(time_obj)
+        return time_obj unless time_obj.respond_to?(:utc)
+
+        time_obj.utc.iso8601.delete(":-")
+      end
+    end
+  end
+end
diff --git a/lib/calendav/requests/list_events.rb b/lib/calendav/requests/list_events.rb
index 4946abc..e0c5b15 100644
--- a/lib/calendav/requests/list_events.rb
+++ b/lib/calendav/requests/list_events.rb
@@ -11,9 +11,10 @@ def self.call(...)
         new(...).call
       end
 
-      def initialize(from:, to:)
+      def initialize(from:, to:, expand: false)
         @from = from
         @to = to
+        @expand = expand
       end
 
       def call
@@ -21,7 +22,9 @@ def call
           xml["caldav"].public_send("calendar-query", NAMESPACES) do
             xml["dav"].prop do
               xml["dav"].getetag
-              xml["caldav"].public_send(:"calendar-data")
+              xml["caldav"].public_send(:"calendar-data") do
+                xml["caldav"].expand(start: from, end: to) if expand?
+              end
             end
             xml["caldav"].filter do
               xml["caldav"].public_send(:"comp-filter", name: "VCALENDAR") do
@@ -55,6 +58,10 @@ def to
       def range?
         to || from
       end
+
+      def expand?
+        @expand
+      end
     end
   end
 end
diff --git a/spec/data/radicale/config.ini b/spec/data/radicale/config.ini
deleted file mode 100644
index 7eb564d..0000000
--- a/spec/data/radicale/config.ini
+++ /dev/null
@@ -1,10 +0,0 @@
-[auth]
-type = htpasswd
-htpasswd_filename = /var/radicale/users
-htpasswd_encryption = bcrypt
-
-[server]
-hosts = 0.0.0.0:8000
-
-[storage]
-filesystem_folder = /var/radicale/collections
diff --git a/spec/data/radicale/users b/spec/data/radicale/users
deleted file mode 100644
index 69b9764..0000000
--- a/spec/data/radicale/users
+++ /dev/null
@@ -1 +0,0 @@
-test:$2y$05$O.Z0365vM0GOv.YN1WlIEOnd0gaGEB/SmoRiSjIHnstXIm6ZURl/y