Simplify permission specs

* Remove iteration if not required
* Unify usage of parentheses for `permissions` call

spec/policies/codeharbor_link_policy_spec.rb

@@ -54,7 +54,7 @@ describe CodeharborLinkPolicy do
       end
     end
 
-    permissions(:enabled?) do
+    permissions :enabled? do
       it 'reflects the config option' do
         %i[external_user admin teacher].each do |factory_name|
           expect(policy).to permit(create(factory_name), codeharbor_link)
@@ -72,7 +72,7 @@ describe CodeharborLinkPolicy do
       allow(codeocean_config).to receive(:read).and_return(codeharbor_config)
     end
 
-    permissions(:enabled?) do
+    permissions :enabled? do
       it 'reflects the config option' do
         %i[external_user admin teacher].each do |factory_name|
           expect(policy).not_to permit(create(factory_name), codeharbor_link)

spec/policies/execution_environment_policy_spec.rb

@@ -7,19 +7,17 @@ describe ExecutionEnvironmentPolicy do
 
   let(:execution_environment) { build(:ruby) }
 
-  [:index?].each do |action|
-    permissions(action) do
-      it 'grants access to admins' do
-        expect(policy).to permit(build(:admin), execution_environment)
-      end
+  permissions :index? do
+    it 'grants access to admins' do
+      expect(policy).to permit(build(:admin), execution_environment)
+    end
 
-      it 'grants access to teachers' do
-        expect(policy).to permit(build(:teacher), execution_environment)
-      end
+    it 'grants access to teachers' do
+      expect(policy).to permit(build(:teacher), execution_environment)
+    end
 
-      it 'does not grant access to external users' do
-        expect(policy).not_to permit(build(:external_user), execution_environment)
-      end
+    it 'does not grant access to external users' do
+      expect(policy).not_to permit(build(:external_user), execution_environment)
     end
   end
 
@@ -59,7 +57,7 @@ describe ExecutionEnvironmentPolicy do
     end
   end
 
-  permissions(:sync_all_to_runner_management?) do
+  permissions :sync_all_to_runner_management? do
     it 'grants access to the admin' do
       expect(policy).to permit(build(:admin))
     end

spec/policies/exercise_policy_spec.rb

@@ -104,41 +104,35 @@ describe ExercisePolicy do
     end
   end
 
-  [:show?].each do |action|
-    permissions(action) do
-      it 'not grants access to external users' do
-        expect(policy).not_to permit(build(:external_user), exercise)
+  permissions :show? do
+    it 'not grants access to external users' do
+      expect(policy).not_to permit(build(:external_user), exercise)
+    end
+  end
+
+  permissions :implement? do
+    it 'grants access to anyone' do
+      %i[admin external_user teacher].each do |factory_name|
+        expect(policy).to permit(build(factory_name), Exercise.new)
       end
     end
   end
 
-  %i[implement?].each do |action|
-    permissions(action) do
+  permissions :submit? do
+    context 'when teacher-defined assessments are available' do
+      before { create(:test_file, context: exercise) }
+
       it 'grants access to anyone' do
         %i[admin external_user teacher].each do |factory_name|
-          expect(policy).to permit(build(factory_name), Exercise.new)
+          expect(policy).to permit(build(factory_name), exercise)
         end
       end
     end
-  end
 
-  %i[submit?].each do |action|
-    permissions(action) do
-      context 'when teacher-defined assessments are available' do
-        before { create(:test_file, context: exercise) }
-
-        it 'grants access to anyone' do
-          %i[admin external_user teacher].each do |factory_name|
-            expect(policy).to permit(build(factory_name), exercise)
-          end
-        end
-      end
-
-      context 'when teacher-defined assessments are not available' do
-        it 'does not grant access to anyone' do
-          %i[admin external_user teacher].each do |factory_name|
-            expect(policy).not_to permit(build(factory_name), exercise)
-          end
+    context 'when teacher-defined assessments are not available' do
+      it 'does not grant access to anyone' do
+        %i[admin external_user teacher].each do |factory_name|
+          expect(policy).not_to permit(build(factory_name), exercise)
         end
       end
     end

spec/policies/external_user_policy_spec.rb

@@ -16,14 +16,12 @@ describe ExternalUserPolicy do
     end
   end
 
-  [:index?].each do |action|
-    permissions(action) do
-      it 'grants access to admins and teachers only' do
-        expect(policy).to permit(build(:admin), ExternalUser.new)
-        expect(policy).to permit(build(:teacher), ExternalUser.new)
-        [:external_user].each do |factory_name|
-          expect(policy).not_to permit(build(factory_name), ExternalUser.new)
-        end
+  permissions :index? do
+    it 'grants access to admins and teachers only' do
+      expect(policy).to permit(build(:admin), ExternalUser.new)
+      expect(policy).to permit(build(:teacher), ExternalUser.new)
+      [:external_user].each do |factory_name|
+        expect(policy).not_to permit(build(factory_name), ExternalUser.new)
       end
     end
   end