Add missing method for all_or_none_of()

CHANGELOG.md

@@ -1,5 +1,6 @@
 0.9.1 (Next)
 ============
+* [#820](https://github.com/intridea/grape/pull/820): Added missing method `all_or_none_of` for the DSL parameters - [@natecj](https://github.com/natecj).
 * [#803](https://github.com/intridea/grape/pull/803): Added `all_or_none_of` parameter validator - [@loveltyoic](https://github.com/loveltyoic).
 * [#774](https://github.com/intridea/grape/pull/774): Extended `mutually_exclusive`, `exactly_one_of`, `at_least_one_of` to work inside any kind of group: `requires` or `optional`, `Hash` or `Array` - [@ShPakvel](https://github.com/ShPakvel).
 * [#743](https://github.com/intridea/grape/pull/743): Added `allow_blank` parameter validator to validate non-empty strings - [@elado](https://github.com/elado).

lib/grape/dsl/parameters.rb

@@ -57,6 +57,10 @@ def at_least_one_of(*attrs)
         validates(attrs, at_least_one_of: true)
       end
 
+      def all_or_none_of(*attrs)
+        validates(attrs, all_or_none_of: true)
+      end
+
       def group(*attrs, &block)
         requires(*attrs, &block)
       end

spec/grape/dsl/parameters_spec.rb

@@ -95,6 +95,14 @@ def valids
         end
       end
 
+      describe '#all_or_none_of' do
+        it 'adds an all or none of parameter validation' do
+          subject.all_or_none_of :media, :audio
+
+          expect(subject.valids).to eq([[:media, :audio], { all_or_none_of: true }])
+        end
+      end
+
       xdescribe '#group' do
         it 'does some thing'
       end