Add test coverage for when rack gem is not loaded

.simplecov

@@ -2,7 +2,7 @@
 
 SimpleCov.start do
   enable_coverage :branch
-  minimum_coverage line: 100, branch: 98.41
+  minimum_coverage line: 100, branch: 100
   add_filter '/spec/'
   add_filter '/vendor/bundle/'
 end

spec/rubocop/cop/rspec_rails/http_status_spec.rb

@@ -89,6 +89,14 @@
 
       expect_no_corrections
     end
+
+    it 'registers no offense when Rack is not loaded' do
+      hide_const('Rack')
+
+      expect_no_offenses(<<~RUBY)
+        it { is_expected.to have_http_status(404) }
+      RUBY
+    end
   end
 
   context 'when EnforcedStyle is `numeric`' do
@@ -163,6 +171,14 @@
         RUBY
       end
     end
+
+    it 'registers no offense when Rack is not loaded' do
+      hide_const('Rack')
+
+      expect_no_offenses(<<~RUBY)
+        it { is_expected.to have_http_status(:not_found) }
+      RUBY
+    end
   end
 
   context 'when EnforcedStyle is `be_status`' do
@@ -287,5 +303,13 @@
         RUBY
       end
     end
+
+    it 'registers no offense when Rack is not loaded' do
+      hide_const('Rack')
+
+      expect_no_offenses(<<~RUBY)
+        it { is_expected.to have_http_status(:not_found) }
+      RUBY
+    end
   end
 end