Bring in ice_nine as a test dependency and implement tests using it

to ensure there are no unnecessary mutations in uri_spec.rb

Gemfile

@@ -5,6 +5,7 @@ gemspec
 group :test do
   gem 'rspec', '~> 3.5'
   gem 'rspec-its', '~> 1.1'
+  gem 'ice_nine', '~> 0.11'
 end
 
 group :development do

spec/addressable/uri_spec.rb

@@ -21,6 +21,8 @@
 require "addressable/uri"
 require "uri"
 require "ipaddr"
+require "ice_nine"
+require "ice_nine/core_ext/object"
 
 if !"".respond_to?("force_encoding")
   class String
@@ -999,6 +1001,67 @@ def to_s
   end
 end
 
+describe Addressable::URI, "when normalized and then deeply frozen" do
+  before do
+    @uri = Addressable::URI.parse(
+      "http://user:password@example.com:8080/path?query=value#fragment"
+    ).normalize!.deep_freeze!
+  end
+
+  it "#normalized_scheme should not error" do
+    expect{ @uri.normalized_scheme }.not_to raise_error
+  end
+
+  it "#normalized_user should not error" do
+    expect{ @uri.normalized_user }.not_to raise_error
+  end
+
+  it "#normalized_password should not error" do
+    expect{ @uri.normalized_password }.not_to raise_error
+  end
+
+  it "#normalized_userinfo should not error" do
+    p @uri.normalized_userinfo
+   expect{ @uri.normalized_userinfo }.not_to raise_error
+  end
+
+  it "#normalized_host should not error" do
+    expect{@uri.normalized_host}.not_to raise_error
+  end
+
+  it "#normalized_authority should not error" do
+    expect{ @uri.normalized_authority }.not_to raise_error
+  end
+
+  it "#normalized_port should not error" do
+    expect{ @uri.normalized_port }.not_to raise_error
+  end
+
+  it "#normalized_site should not error" do
+    expect{ @uri.normalized_site }.not_to raise_error
+  end
+
+  it "#normalized_path should not error" do
+    expect{ @uri.normalized_path }.not_to raise_error
+  end
+
+  it "#normalized_query should not error" do
+    expect{ @uri.normalized_query }.not_to raise_error
+  end
+
+  it "#normalized_fragment should not error" do
+   expect{ @uri.normalized_fragment }.not_to raise_error
+  end
+
+  it "should be frozen" do
+    expect(@uri).to be_frozen
+  end
+
+  it "should not allow destructive operations" do
+    expect { @uri.normalize! }.to raise_error(FrozenError)
+  end
+end
+
 describe Addressable::URI, "when created from string components" do
   before do
     @uri = Addressable::URI.new(