Add create_go_makefile skeleton

Author: sue445

gem/lib/go_gem/mkmf.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "mkmf"
+
+module GoGem
+  # Helper module for creating Go Makefiles
+  module Mkmf
+    # @param target [String]
+    # @param srcprefix [String,nil]
+    def create_go_makefile(target, srcprefix = nil)
+      create_makefile(target, srcprefix)
+    end
+  end
+end
+
+include GoGem::Mkmf # rubocop:disable Style/MixinUsage

gem/spec/go_gem/mkmf_spec.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+RSpec.describe GoGem::Mkmf do
+  describe "#create_go_makefile" do
+    gem_name = "new_gem"
+
+    before(:all) do
+      @temp_dir = Dir.mktmpdir
+
+      Dir.chdir(@temp_dir) do
+        create_go_makefile("#{gem_name}/#{gem_name}")
+      end
+    end
+
+    after(:all) do
+      FileUtils.remove_entry_secure(@temp_dir) if @temp_dir && Dir.exist?(@temp_dir)
+    end
+
+    around do |example|
+      Dir.chdir(@temp_dir) do
+        example.run
+      end
+    end
+
+    describe file("Makefile") do
+      it { should be_file }
+      it { should exist }
+
+      # content of create_makefile
+      its(:content) { should match(%r{^SHELL = /bin/sh$}) }
+
+      # content of create_go_makefile
+      its(:content) { should match(%r{^\$\(DLLIB\): Makefile \$\(srcdir\)/\*\.go$}) }
+    end
+  end
+end

gem/spec/go_gem_spec.rb

@@ -1,6 +1,12 @@
 # frozen_string_literal: true
 
 require "go_gem"
+require "go_gem/mkmf"
+
+require "tmpdir"
+require "serverspec"
+
+set :backend, :exec
 
 RSpec.configure do |config|
   # Enable flags like --only-failures and --next-failure
@@ -12,4 +18,10 @@
   config.expect_with :rspec do |c|
     c.syntax = :expect
   end
+
+  config.filter_run_when_matching :focus
+
+  config.define_derived_metadata do |meta|
+    meta[:aggregate_failures] = true
+  end
 end