Add Excluded property to the rule

spec/ameba/formatter/todo_formatter_spec.cr

@@ -1,43 +1,54 @@
 require "../../spec_helper"
 
 module Ameba
-  private def create_todo(formatter)
-    s = Source.new "a = 1"
+  private def create_todo
+    file = IO::Memory.new
+    formatter = Formatter::TODOFormatter.new IO::Memory.new, file
+
+    s = Source.new "a = 1", "source.cr"
     s.error DummyRule.new, s.location(1, 2), "message"
+
     formatter.finished [s]
+    file.to_s
   end
 
   describe Formatter::TODOFormatter do
-    file = IO::Memory.new
-    subject = Formatter::TODOFormatter.new IO::Memory.new, file
-
-    context "problems not reported" do
+    context "problems not found" do
       it "does not create todo" do
-        subject.finished [Source.new ""]
+        file = IO::Memory.new
+        formatter = Formatter::TODOFormatter.new IO::Memory.new, file
+        formatter.finished [Source.new ""]
         file.to_s.empty?.should be_true
       end
     end
 
-    context "problems reported" do
-      it "creates a todo with header" do
-        create_todo subject
-        file.to_s.should contain "# This configuration file was generated by"
-        file.to_s.should contain "Ameba version #{VERSION}"
+    context "problems found" do
+      it "creates a valid YAML document" do
+        YAML.parse(create_todo).should_not be_nil
       end
 
-      it "creates a todo with rule name" do
-        create_todo subject
-        file.to_s.should contain "DummyRule"
+      it "creates a todo with header" do
+        create_todo.should contain "# This configuration file was generated by"
+      end
+
+      it "creates a todo with version" do
+        create_todo.should contain "Ameba version #{VERSION}"
+      end
+
+      it "creates a todo with a rule name" do
+        create_todo.should contain "DummyRule"
       end
 
       it "creates a todo with problems count" do
-        create_todo subject
-        file.to_s.should contain "Problems found: 1"
+        create_todo.should contain "Problems found: 1"
       end
 
-      it "creates a valid YAML document" do
-        create_todo subject
-        YAML.parse(file.to_s).should_not be_nil
+      it "creates a todo with run details" do
+        create_todo.should contain "Run `ameba --only #{DummyRule.class_name}`"
+      end
+
+      it "excludes source from this rule" do
+        create_todo.should contain "Excluded:\n  - source.cr"
       end
     end
   end