Implement `test_macro' recipe keyword

lib/producer/core/condition.rb

@@ -2,9 +2,9 @@ module Producer
   module Core
     class Condition
       class << self
-        def evaluate(env, &block)
+        def evaluate(env, *args, &block)
           dsl = DSL.new(env, &block)
-          return_value = dsl.evaluate
+          return_value = dsl.evaluate *args
           Condition.new(dsl.tests, return_value)
         end
       end

lib/producer/core/condition/dsl.rb

@@ -3,12 +3,21 @@ module Producer
     class Condition
       class DSL
         class << self
-          def define_test(keyword, klass)
-            define_method(keyword) do |*args|
-              @tests << klass.new(@env, *args)
-            end
-            define_method("no_#{keyword}") do |*args|
-              @tests << klass.new(@env, *args, negated: true)
+          def define_test(keyword, test)
+            {
+              keyword         => false,
+              "no_#{keyword}" => true
+            }.each do |kw, negated|
+              define_method(kw) do |*args|
+                if test.respond_to? :call
+                  args  = [test, *args]
+                  klass = Tests::ConditionTest
+                else
+                  klass = test
+                end
+                t = klass.new(@env, *args, negated: negated)
+                @tests << t
+              end
             end
           end
         end
@@ -29,8 +38,8 @@ module Producer
           @tests  = []
         end
 
-        def evaluate
-          instance_eval &@block
+        def evaluate(*args)
+          instance_exec *args, &@block
         end
       end
     end

lib/producer/core/recipe/dsl.rb

@@ -38,6 +38,10 @@ module Producer
           end
         end
 
+        def test_macro(name, dsl: Condition::DSL, &block)
+          dsl.define_test(name, block)
+        end
+
         def set(key, value)
           env[key] = value
         end

lib/producer/core/tests/condition_test.rb

@@ -0,0 +1,23 @@
+module Producer
+  module Core
+    module Tests
+      class ConditionTest < Test
+        def verify
+          condition.met?
+        end
+
+        def condition
+          Condition.evaluate(env, *condition_args, &condition_block)
+        end
+
+        def condition_args
+          arguments.drop 1
+        end
+
+        def condition_block
+          arguments.first
+        end
+      end
+    end
+  end
+end