Add a more useful error for when permissions is forgotten in rspec

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Changed
+
+- Using `permit` matcher without a surrouding `permissions` block now raises a useful error. (#836)
+
 ## 2.4.0 (2024-08-26)
 
 ## Changed

lib/pundit/rspec.rb

@@ -93,7 +93,11 @@ def current_example
         end
 
         def permissions
-          current_example.metadata[:permissions]
+          current_example.metadata.fetch(:permissions) do
+            raise KeyError, <<~ERROR.strip
+              No permissions in example metadata, did you forget to wrap with `permissions :show?, ...`?
+            ERROR
+          end
         end
       end
       # rubocop:enable Metrics/BlockLength

spec/rspec_dsl_spec.rb

@@ -36,6 +36,16 @@
   end
 
   describe "#permit" do
+    context "when not appropriately wrapped in permissions" do
+      it "raises a descriptive error" do
+        expect do
+          expect(policy).to permit(user, post)
+        end.to raise_error(KeyError, <<~MSG.strip)
+          No permissions in example metadata, did you forget to wrap with `permissions :show?, ...`?
+        MSG
+      end
+    end
+
     permissions :edit?, :update? do
       it "succeeds when action is permitted" do
         expect(policy).to permit(user, post)