Fix Rails/TimeZone cop error on invalid string literal encoding

In some cases (e.g. for testing purposes) we might to want
to use invalid string literal -- in that case IMO we should
not register an offense.

Author: viralpraxis

changelog/fix_rails_time_zone_cop_error_on_invalid_string_literal_encoding.md

@@ -0,0 +1 @@
+* [#1475](https://github.com/rubocop/rubocop-rails/pull/1475): Fix `Rails/TimeZone` cop error on invalid string literal encoding. ([@viralpraxis][])

lib/rubocop/cop/rails/time_zone.rb

@@ -135,7 +135,9 @@ def check_time_node(klass, node)
         end
 
         def attach_timezone_specifier?(date)
-          date.respond_to?(:value) && TIMEZONE_SPECIFIER.match?(date.value.to_s)
+          return false unless date.respond_to?(:value)
+
+          !date.value.to_s.valid_encoding? || TIMEZONE_SPECIFIER.match?(date.value.to_s)
         end
 
         def build_message(klass, method_name, node)

spec/rubocop/cop/rails/time_zone_spec.rb

@@ -1,9 +1,19 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Rails::TimeZone, :config do
+  shared_examples 'with invalid timezone literal encoding' do
+    it 'does not register an offense' do
+      expect_no_offenses(<<~'RUBY')
+        Time.new("l\366, 26 maj 2001 00:15:58")
+      RUBY
+    end
+  end
+
   context 'when EnforcedStyle is "strict"' do
     let(:cop_config) { { 'EnforcedStyle' => 'strict' } }
 
+    include_context 'with invalid timezone literal encoding'
+
     it 'registers an offense for Time.now' do
       expect_offense(<<~RUBY)
         Time.now
@@ -334,6 +344,8 @@
   context 'when EnforcedStyle is "flexible"' do
     let(:cop_config) { { 'EnforcedStyle' => 'flexible' } }
 
+    include_context 'with invalid timezone literal encoding'
+
     it 'registers an offense for Time.now' do
       expect_offense(<<~RUBY)
         Time.now