Implement condition DSL negated test prefix (no_*)

* Allow no_* to be used for every tests in condition DSL:
  condition { no_has_env :shell, '/bin/sh' };
* Modify Test constructor to accept negated: named argument, implement
  #negated? and #pass?;
* Rename #success? to #verify in all test classes.

spec/producer/core/condition/dsl_spec.rb

@@ -49,6 +49,10 @@ module Producer::Core
       it 'defines a new test keyword' do
         expect(dsl).to respond_to :some_test
       end
+
+      it 'defines the negated test' do
+        expect(dsl).to respond_to :no_some_test
+      end
     end
 
     describe '#initialize' do
@@ -96,6 +100,16 @@ module Producer::Core
           dsl.evaluate
           expect(dsl.tests).to include(some_test)
         end
+
+        context 'when keyword is prefixed with "no_"' do
+          let(:block) { proc { no_some_test :some, :args } }
+
+          it 'builds a negated test' do
+            expect(some_test_class)
+              .to receive(:new).with(env, :some, :args, negated: true)
+            dsl.evaluate
+          end
+        end
       end
     end
   end