Prevent overwrite of Slim embedded options (#1927)

* Fix middleman/middleman#1925: Slim embedded options overwrite

* Remove context_hack from Slim renderer

* Remove debugging output

middleman-core/features/markdown_redcarpet_in_slim.feature

@@ -0,0 +1,41 @@
+Feature: Markdown support in Slim
+  In order to test support of the Slim markdown filter
+
+  Scenario: Markdown filter in Slim works
+    Given a fixture app "markdown-in-slim-app"
+    And a file named "config.rb" with:
+      """
+      set :markdown_engine, :redcarpet
+      activate :directory_indexes
+      """
+    And a file named "source/markdown_filter.html.slim" with:
+      """
+      markdown:
+        # H1
+
+        paragraph
+      """
+    Given the Server is running at "markdown-in-slim-app"
+    When I go to "/markdown_filter/"
+    Then I should see ">H1</h1>"
+    Then I should see "<p>paragraph</p>"
+
+
+  Scenario: Markdown filter in Slim uses our link_to and image_tag helpers
+    Given a fixture app "markdown-in-slim-app"
+    And a file named "config.rb" with:
+      """
+      set :markdown_engine, :redcarpet
+      activate :directory_indexes
+      """
+    And a file named "source/link_and_image.html.slim" with:
+      """
+      markdown:
+        [A link](/link_target.html)
+
+        ![image](blank.gif)
+      """
+    Given the Server is running at "markdown-in-slim-app"
+    When I go to "/link_and_image/"
+    Then I should see "/link_target/"
+    Then I should see 'src="/images/blank.gif"'

middleman-core/features/sass_in_slim.feature

@@ -0,0 +1,40 @@
+Feature: Sass/SCSS support in Slim
+  In order to test support of the Slim sass and scss filters
+
+  Scenario: Sass filter in Slim works
+    Given a fixture app "sass-in-slim-app"
+    And a file named "config.rb" with:
+      """
+      activate :directory_indexes
+      """
+    And a file named "source/sass_filter.html.slim" with:
+      """
+      sass:
+        .sass
+          margin: 0
+      """
+    Given the Server is running at "sass-in-slim-app"
+    When I go to "/sass_filter/"
+    Then I should see "text/css"
+    Then I should see ".sass"
+    Then I should see "margin:0"
+
+
+  Scenario: SCSS filter in Slim works
+    Given a fixture app "sass-in-slim-app"
+    And a file named "config.rb" with:
+      """
+      activate :directory_indexes
+      """
+    And a file named "source/scss_filter.html.slim" with:
+      """
+      scss:
+        .scss {
+          margin: 0;
+        }
+      """
+    Given the Server is running at "sass-in-slim-app"
+    When I go to "/scss_filter/"
+    Then I should see "text/css"
+    Then I should see ".scss"
+    Then I should see "margin:0"

middleman-core/lib/middleman-core/renderers/slim.rb

@@ -12,13 +12,9 @@ class ::Slim::Template
 
   def initialize(file, line, opts, &block)
     if opts.key?(:context)
-      context_hack = {
-        context: opts[:context]
-      }
-
       ::Slim::Embedded::SassEngine.disable_option_validator!
       %w(sass scss markdown).each do |engine|
-        ::Slim::Embedded.options[engine.to_sym] = context_hack
+        (::Slim::Embedded.options[engine.to_sym] ||= {})[:context] = opts[:context]
       end
     end