add test to discuss #65.

test/call_test.rb

@@ -41,18 +41,18 @@ class Update < Trailblazer::Operation
     result.event.must_equal Update.to_h[:outputs].find { |output| output.semantic == :failure }.signal
   end
 
+  def self.add_1(wrap_ctx, original_args)
+    ctx, = original_args[0]
+    ctx[:seq] << 1
+    return wrap_ctx, original_args # yay to mutable state. not.
+  end
+
   it "invokes with the taskWrap" do
     operation = Class.new(Trailblazer::Operation) do
       include Trailblazer::Activity::Testing.def_steps(:a)
 
-      def self.add_1(wrap_ctx, original_args)
-        ctx, = original_args[0]
-        ctx[:seq] << 1
-        return wrap_ctx, original_args # yay to mutable state. not.
-      end
-
       merge = [
-        [Trailblazer::Activity::TaskWrap::Pipeline.method(:insert_before), "task_wrap.call_task", ["user.add_1", method(:add_1)]]
+        [Trailblazer::Activity::TaskWrap::Pipeline.method(:insert_before), "task_wrap.call_task", ["user.add_1", CallTest.method(:add_1)]]
       ]
 
       step :a, extensions: [Trailblazer::Activity::TaskWrap::Extension(merge: merge)]
@@ -70,4 +70,27 @@ def self.add_1(wrap_ctx, original_args)
 
     result.wtf?
   end
+
+
+  it "calls with the taskWrap defined for operation using circuit interface" do
+    operation = Class.new(Trailblazer::Operation) do
+      include Trailblazer::Activity::Testing.def_steps(:a)
+
+      step :a
+    end
+
+    my_extension = Trailblazer::Activity::TaskWrap::Extension(
+      [CallTest.method(:add_1), id: "my.add_1", append: "task_wrap.call_task"]
+    )
+
+    # circuit interface invocation using call
+    signal, (ctx, _) = operation.call(
+      [{seq: []}, {}],
+      wrap_runtime: Hash.new(my_extension),
+      runner: Trailblazer::Activity::TaskWrap::Runner
+    )
+
+    assert_equal signal.to_h[:semantic], :success
+    assert_equal ctx[:seq], [1, :a, 1, 1]
+  end
 end