test cyclic includes

tests/ruby/include_spec.rb

@@ -0,0 +1,13 @@
+#!/usr/bin/env rspec
+
+require_relative "test_helper_rspec"
+
+require "yast"
+
+module Yast
+  describe ".include" do
+    it "does not loop endlessly on cyclic includes" do
+      expect { Yast.include(Yast, "cyclic_yin.rb") }.not_to raise_error
+    end
+  end
+end

tests/ruby/test_module/include/cyclic_yang.rb

@@ -0,0 +1,11 @@
+module Yast
+  module CyclicYangInclude
+    def initialize_cyclic_yang(include_target)
+      Yast.include include_target, "cyclic_yin.rb"
+    end
+
+    def yang
+      "YANG"
+    end
+  end
+end

tests/ruby/test_module/include/cyclic_yin.rb

@@ -0,0 +1,11 @@
+module Yast
+  module CyclicYinInclude
+    def initialize_cyclic_yin(include_target)
+      Yast.include include_target, "cyclic_yang.rb"
+    end
+
+    def yin
+      "YIN"
+    end
+  end
+end