Test invalid array values through checkboxes

spec/integration/on_invalid_spec.rb

@@ -94,12 +94,14 @@ def query_of(url)
       expect(page).to have_no_content("drop me")
     end
 
-    it "validates array elements emptied by the sanitizer and preserves the original input" do
-      visit "/admin/empty_digits_posts?q%5Bposition_eq%5D%5B%5D=abc"
+    it "validates array elements emptied by the sanitizer and keeps a checkbox input" do
+      visit "/admin/empty_digits_array_posts"
+      check "Not a number"
+      click_button "Filter"
 
       expect(page).to have_content("filter has an invalid value")
-      expect(query_of(page.current_url)["q"]).to eq("position_eq" => ["abc"])
-      expect(page).to have_field("q[position_eq]", with: "0")
+      expect(query_of(page.current_url)["q"]).to eq("status_in" => ["abc"])
+      expect(page).to have_checked_field("q[status_in][]", with: "abc")
       expect(page).to have_no_content("keep me")
       expect(page).to have_no_content("drop me")
     end

spec/support/rails_template.rb

@@ -517,6 +517,14 @@ def filter_defaults_apply?
                           extensions: { sanitize: :digits, validate: :integer, on_invalid: :empty }
     end
 
+    ActiveAdmin.register Post, as: "EmptyDigitsArrayPost" do
+      # A genuine multi-value filter: unlike the scalar filter above, its check boxes submit
+      # q[status_in][] and can therefore render the preserved array back to the admin.
+      filter :status, as: :check_boxes,
+                      collection: [["Not a number", "abc"], "draft", "published"],
+                      extensions: { sanitize: :digits, validate: :integer, on_invalid: :empty }
+    end
+
     ActiveAdmin.register Post, as: "RejectWindowPost" do
       # Value AND window policies on one :reject filter: the second violation must not answer
       # an already-answered request.