Add concept of Liquid::Environment (#1815)

* Add concept of `Liquid::World`

* Rename `World` to `Environment`

test/test_helper.rb

@@ -42,10 +42,11 @@ module Minitest
       message: nil, partials: nil, error_mode: nil, render_errors: false,
       template_factory: nil
     )
-      template = Liquid::Template.parse(template, line_numbers: true, error_mode: error_mode&.to_sym)
       file_system = StubFileSystem.new(partials || {})
+      environment = Liquid::Environment.build(file_system: file_system)
+      template = Liquid::Template.parse(template, line_numbers: true, error_mode: error_mode&.to_sym, environment: environment)
       registers = Liquid::Registers.new(file_system: file_system, template_factory: template_factory)
-      context = Liquid::Context.build(static_environments: assigns, rethrow_errors: !render_errors, registers: registers)
+      context = Liquid::Context.build(static_environments: assigns, rethrow_errors: !render_errors, registers: registers, environment: environment)
       output = template.render(context)
       assert_equal(expected, output, message)
     end
@@ -78,22 +79,12 @@ module Minitest
       assert_equal(times, calls, "Number of calls to Usage.increment with #{name.inspect}")
     end
 
-    def with_global_filter(*globals)
-      original_global_cache = Liquid::StrainerFactory::GlobalCache
-      Liquid::StrainerFactory.send(:remove_const, :GlobalCache)
-      Liquid::StrainerFactory.const_set(:GlobalCache, Class.new(Liquid::StrainerTemplate))
+    def with_global_filter(*globals, &blk)
+      environment = Liquid::Environment.build do |w|
+        w.register_filters(globals)
+      end
 
-      globals.each do |global|
-        Liquid::Template.register_filter(global)
-      end
-      Liquid::StrainerFactory.send(:strainer_class_cache).clear
-      begin
-        yield
-      ensure
-        Liquid::StrainerFactory.send(:remove_const, :GlobalCache)
-        Liquid::StrainerFactory.const_set(:GlobalCache, original_global_cache)
-        Liquid::StrainerFactory.send(:strainer_class_cache).clear
-      end
+      Environment.dangerously_override(environment, &blk)
     end
 
     def with_error_mode(mode)
@@ -104,18 +95,11 @@ module Minitest
       Liquid::Template.error_mode = old_mode
     end
 
-    def with_custom_tag(tag_name, tag_class)
-      old_tag = Liquid::Template.tags[tag_name]
-      begin
-        Liquid::Template.register_tag(tag_name, tag_class)
-        yield
-      ensure
-        if old_tag
-          Liquid::Template.tags[tag_name] = old_tag
-        else
-          Liquid::Template.tags.delete(tag_name)
-        end
-      end
+    def with_custom_tag(tag_name, tag_class, &block)
+      environment = Liquid::Environment.default.dup
+      environment.register_tag(tag_name, tag_class)
+
+      Environment.dangerously_override(environment, &block)
     end
   end
 end