feat(fetch): add default behavior

Author: sanemat

lib/env_pull_request/base.rb

@@ -1,7 +1,17 @@
 module EnvPullRequest
   class Base
-    def pull_request_id
-      1
+    attr_reader :pull_request_id
+
+    def initialize
+      @pull_request_id = fetch_pull_request_id
+    end
+
+    def fetch_pull_request_id
+      nil
+    end
+
+    def pull_request?
+      !pull_request_id.nil?
     end
   end
 end

test/test_ci.rb

@@ -0,0 +1,20 @@
+require_relative 'helper'
+
+module EnvPullRequest
+  class TestCi < Test::Unit::TestCase
+    sub_test_case 'not pull request' do
+      test '#pull_request?' do
+        env = EnvPullRequest.new
+        assert do
+          env.pull_request? == false
+        end
+      end
+      test '#pull_request_id' do
+        env = EnvPullRequest.new
+        assert do
+          env.pull_request_id.nil?
+        end
+      end
+    end
+  end
+end