Fix minor issues

Author: gcatanese

lib/adyen/client.rb

@@ -51,7 +51,7 @@ def initialize(ws_user: nil, ws_password: nil, api_key: nil, oauth_token: nil, e
 
     # make sure that env can only be :live, :test, or :mock
     def env=(value)
-      raise ArgumentError, "Invalid value for Client.env: '#{value}'' - must be one of [:live, :test, :mock]" unless %i[
+      raise ArgumentError, "Invalid value for Client.env: '#{value}' - must be one of [:live, :test, :mock]" unless %i[
         live test mock
       ].include? value
 
@@ -60,10 +60,7 @@ def env=(value)
 
     # remove 'https' from live_url_prefix if necessary
     def live_url_prefix=(value)
-      unless value.nil?
-        value['https://'] = '' unless value['https://'].nil?
-      end
-      @live_url_prefix = value
+      @live_url_prefix = value.nil? ? value : value.sub('https://', '')
     end
 
     # base URL for API given service and @env

spec/client_spec.rb

@@ -34,6 +34,12 @@
       .to eq('https://myprefix-pal-live.adyenpayments.com/pal/servlet/Payment')
   end
 
+  it 'does not mutate the original live_url_prefix string' do
+    prefix = 'https://myprefix'
+    Adyen::Client.new(env: :live, live_url_prefix: prefix)
+    expect(prefix).to eq('https://myprefix')
+  end
+
   it 'sets the version number' do
     @shared_values[:client].checkout.version = @shared_values[:version]
     expect(@shared_values[:client].checkout.version)