wrote failing tests to prove condition of lambda and coercion working…

… correctly

spec/grape/validations/validators/values_spec.rb

@@ -54,6 +54,13 @@ class API < Grape::API
             { type: params[:type] }
           end
 
+          params do
+            requires :type, values: { except: -> { ValuesModel.excepts }, except_message: 'value is on exclusions list' }
+          end
+          get '/exclude/lambda/exclude_message' do
+            { type: params[:type] }
+          end
+
           params do
             requires :type, values: { except: ValuesModel.excepts, message: 'default exclude message' }
           end
@@ -132,6 +139,20 @@ class API < Grape::API
           { type: params[:type] }
         end
 
+        params do
+          requires :type, values: { except: -> { ValuesModel.excepts } }
+        end
+        get '/except/exclusive/lambda' do
+          { type: params[:type] }
+        end
+
+        params do
+          requires :type, type: Integer, values: { except: -> { [3, 4, 5] } }
+        end
+        get '/except/exclusive/lambda/coercion' do
+          { type: params[:type] }
+        end
+
         params do
           requires :type, type: Integer, values: { value: 1..5, except: [3] }
         end
@@ -182,6 +203,14 @@ def app
     end
   end
 
+  context 'with a custom exclude validation message' do
+    it 'does not allow an invalid value for a parameter' do
+      get('/custom_message/exclude/lambda/exclude_message', type: 'invalid-type1')
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type value is on exclusions list' }.to_json)
+    end
+  end
+
   context 'exclude with a standard custom validation message' do
     it 'does not allow an invalid value for a parameter' do
       get('/custom_message/exclude/fallback_message', type: 'invalid-type1')
@@ -391,6 +420,34 @@ def app
     end
   end
 
+  context 'exclusive excepts with lambda' do
+    it 'allows any other value outside excepts' do
+      get '/except/exclusive/lambda', type: 'value'
+      expect(last_response.status).to eq 200
+      expect(last_response.body).to eq({ type: 'value' }.to_json)
+    end
+
+    it 'rejects values that matches except' do
+      get '/except/exclusive/lambda', type: 'invalid-type1'
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type has a value not allowed' }.to_json)
+    end
+  end
+
+  context 'exclusive excepts with lambda and coercion' do
+    it 'allows any other value outside excepts' do
+      get '/except/exclusive/lambda/coercion', type: 'value'
+      expect(last_response.status).to eq 200
+      expect(last_response.body).to eq({ type: 'value' }.to_json)
+    end
+
+    it 'rejects values that matches except' do
+      get '/except/exclusive/lambda/coercion', type: 'invalid-type1'
+      expect(last_response.status).to eq 400
+      expect(last_response.body).to eq({ error: 'type has a value not allowed' }.to_json)
+    end
+  end
+
   context 'with mixed values and excepts' do
     it 'allows value, but not in except' do
       get '/mixed/value/except', type: 2