diff --git a/Library/Homebrew/test/cask/dsl/container_spec.rb b/Library/Homebrew/test/cask/dsl/container_spec.rb
new file mode 100644
index 0000000000..e291bf0b24
--- /dev/null
+++ b/Library/Homebrew/test/cask/dsl/container_spec.rb
@@ -0,0 +1,36 @@
+# typed: false
+# frozen_string_literal: true
+
+require "test/cask/dsl/shared_examples/base"
+
+describe Cask::DSL::Container do
+  subject(:container) { described_class.new(**params) }
+
+  describe "#pairs" do
+    let(:params) { { nested: "NestedApp.dmg" } }
+
+    it "returns the attributes as a hash" do
+      expect(container.pairs).to eq(nested: "NestedApp.dmg")
+    end
+  end
+
+  describe "#to_s" do
+    let(:params) { { nested: "NestedApp.dmg", type: :naked } }
+
+    it "returns the stringified attributes" do
+      expect(container.to_s).to eq('{:nested=>"NestedApp.dmg", :type=>:naked}')
+    end
+  end
+
+  describe "#to_yaml" do
+    let(:params) { { nested: "NestedApp.dmg", type: :naked } }
+
+    it "returns the attributes in YAML format" do
+      expect(container.to_yaml).to eq(<<~YAML)
+        ---
+        :nested: NestedApp.dmg
+        :type: :naked
+      YAML
+    end
+  end
+end