assert_file understands paths with special characters

fixes rails#20042

Author: dcrec1

railties/lib/rails/generators/testing/assertions.rb

@@ -23,7 +23,7 @@ module Assertions
         #     end
         #   end
         def assert_file(relative, *contents)
-          absolute = File.expand_path(relative, destination_root).shellescape
+          absolute = File.expand_path(relative, destination_root)
           assert File.exist?(absolute), "Expected file #{relative.inspect} to exist, but does not"
 
           read = File.read(absolute) if block_given? || !contents.empty?

railties/test/generators/app_generator_test.rb

@@ -499,7 +499,7 @@ def test_pretend_option
   end
 
   def test_application_name_with_spaces
-    path = File.join(destination_root, "foo bar".shellescape)
+    path = File.join(destination_root, "foo bar")
 
     # This also applies to MySQL apps but not with SQLite
     run_generator [path, "-d", 'postgresql']

railties/test/railties/generators_test.rb

@@ -122,5 +122,13 @@ def test_helpers_are_not_namespaced_when_engine_is_not_mountable
         assert_no_file "app/helpers/foo_bar/topics_helper.rb"
       end
     end
+
+    def test_assert_file_founds_files_with_special_characters
+      path = "#{app_path}/tmp"
+      file_name = "#{path}/v0.1.4~alpha+nightly"
+      FileUtils.mkdir_p path
+      FileUtils.touch file_name
+      assert_file file_name
+    end
   end
 end