8 files changed, 17 insertions, 0 deletions
diff --git a/actionpack/test/fixtures/test/_changing_priority.html.erb b/actionpack/test/fixtures/test/_changing_priority.html.erb
new file mode 100644
index 0000000000..3225efc49a
--- /dev/null
+++ b/actionpack/test/fixtures/test/_changing_priority.html.erb
@@ -0,0 +1 @@
+HTML
+\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/_changing_priority.json.erb b/actionpack/test/fixtures/test/_changing_priority.json.erb
new file mode 100644
index 0000000000..7fa41dce66
--- /dev/null
+++ b/actionpack/test/fixtures/test/_changing_priority.json.erb
@@ -0,0 +1 @@
+JSON
+\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/_first_json_partial.json.erb b/actionpack/test/fixtures/test/_first_json_partial.json.erb
new file mode 100644
index 0000000000..790ee896db
--- /dev/null
+++ b/actionpack/test/fixtures/test/_first_json_partial.json.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/second_json_partial" %>
+\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/_json_change_priority.json.erb b/actionpack/test/fixtures/test/_json_change_priority.json.erb
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/actionpack/test/fixtures/test/_json_change_priority.json.erb
diff --git a/actionpack/test/fixtures/test/_second_json_partial.json.erb b/actionpack/test/fixtures/test/_second_json_partial.json.erb
new file mode 100644
index 0000000000..5ebb7f1afd
--- /dev/null
+++ b/actionpack/test/fixtures/test/_second_json_partial.json.erb
@@ -0,0 +1 @@
+Third level
+\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/change_priorty.html.erb b/actionpack/test/fixtures/test/change_priorty.html.erb
new file mode 100644
index 0000000000..5618977d05
--- /dev/null
+++ b/actionpack/test/fixtures/test/change_priorty.html.erb
@@ -0,0 +1,2 @@
+<%= render :partial => "test/json_change_priority", formats: :json %>
+HTML Template, but <%= render :partial => "test/changing_priority" %> partial
+\ No newline at end of file
diff --git a/actionpack/test/fixtures/test/html_template.html.erb b/actionpack/test/fixtures/test/html_template.html.erb
new file mode 100644
index 0000000000..1bbc2b7f09
--- /dev/null
+++ b/actionpack/test/fixtures/test/html_template.html.erb
@@ -0,0 +1 @@
+<%= render :partial => "test/first_json_partial", formats: :json %>
+\ No newline at end of file
diff --git a/actionpack/test/template/render_test.rb b/actionpack/test/template/render_test.rb
index b907e3297b..f20b1c358e 100644
--- a/actionpack/test/template/render_test.rb
+++ b/actionpack/test/template/render_test.rb
@@ -54,6 +54,16 @@ module RenderTestCases
     assert_equal "Hello world", @view.render(:template => "test/one", :formats => [:html])
   end
 
+  def test_render_partial_implicitly_use_format_of_the_rendered_partial
+    @view.lookup_context.formats = [:html]
+    assert_equal "Third level", @view.render(:template => "test/html_template")
+  end
+
+  def test_render_partial_use_last_prepended_format_for_partials_with_the_same_names
+    @view.lookup_context.formats = [:html]
+    assert_equal "\nHTML Template, but JSON partial", @view.render(:template => "test/change_priorty")
+  end
+
   def test_render_template_with_a_missing_partial_of_another_format
     @view.lookup_context.formats = [:html]
     assert_raise ActionView::Template::Error, "Missing partial /missing with {:locale=>[:en], :formats=>[:json], :handlers=>[:erb, :builder]}" do