diff --git a/README.md b/README.md
index 5eba528..a311f97 100644
--- a/README.md
+++ b/README.md
@@ -200,6 +200,7 @@ end
 
 RSpec.describe Log do
   it { is_expected.to be_stored_in :logs }
+  it { is_expected.to be_dynamic_document }
 end
 
 RSpec.describe Article do
diff --git a/lib/matchers/document.rb b/lib/matchers/document.rb
index ffce435..e98c815 100644
--- a/lib/matchers/document.rb
+++ b/lib/matchers/document.rb
@@ -161,3 +161,13 @@ def have_field(*args)
     "be a multiparameted Mongoid document"
   end
 end
+
+RSpec::Matchers.define :be_dynamic_document do |_|
+  match do |doc|
+    doc.class.included_modules.include?(Mongoid::Attributes::Dynamic)
+  end
+
+  description do
+    'be a Mongoid document with dynamic attributes'
+  end
+end
diff --git a/spec/models/log.rb b/spec/models/log.rb
index 92c38ed..bd7f3e4 100644
--- a/spec/models/log.rb
+++ b/spec/models/log.rb
@@ -1,6 +1,8 @@
 class Log
   include Mongoid::Document
   include Mongoid::Timestamps
+  include Mongoid::Attributes::Dynamic
+
   store_in collection: "logs"
 
   index({ created_at: 1 }, { bucket_size: 100, expire_after_seconds: 3600 } )
diff --git a/spec/unit/document_spec.rb b/spec/unit/document_spec.rb
index 7694792..c0cad38 100644
--- a/spec/unit/document_spec.rb
+++ b/spec/unit/document_spec.rb
@@ -18,4 +18,9 @@
     it { is_expected.to be_mongoid_document }
     it { is_expected.to be_timestamped_document }
   end
+
+  describe Log do
+    it { is_expected.to be_mongoid_document }
+    it { is_expected.to be_dynamic_document }
+  end
 end