tests: support Linux kernels with CONFIG_IPV6=n

Detecting the presence of constants in C headers is insufficient,
as a Linux kernel can be built with CONFIG_IPV6=n

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65055 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/library/socket/basicsocket/setsockopt_spec.rb

@@ -237,13 +237,15 @@ describe 'BasicSocket#setsockopt' do
         @socket.getsockopt(:IP, :TTL).int.should == 255
       end
 
-      it 'sets an IPv6 boolean option' do
-        socket = Socket.new(:INET6, :STREAM)
-        begin
-          socket.setsockopt(:IPV6, :V6ONLY, true).should == 0
-          socket.getsockopt(:IPV6, :V6ONLY).bool.should == true
-        ensure
-          socket.close
+      guard -> { SocketSpecs.ipv6_available? } do
+        it 'sets an IPv6 boolean option' do
+          socket = Socket.new(:INET6, :STREAM)
+          begin
+            socket.setsockopt(:IPV6, :V6ONLY, true).should == 0
+            socket.getsockopt(:IPV6, :V6ONLY).bool.should == true
+          ensure
+            socket.close
+          end
         end
       end
 

spec/ruby/library/socket/fixtures/classes.rb

@@ -50,7 +50,7 @@ module SocketSpecs
   def self.ipv6_available?
     @ipv6_available ||= begin
       server = TCPServer.new('::1', 0)
-    rescue Errno::EADDRNOTAVAIL, SocketError
+    rescue Errno::EAFNOSUPPORT, Errno::EADDRNOTAVAIL, SocketError
       :no
     else
       server.close

spec/ruby/library/socket/socket/ipv6only_bang_spec.rb

@@ -1,17 +1,19 @@
 require_relative '../spec_helper'
 
-describe 'Socket#ipv6only!' do
-  before do
-    @socket = Socket.new(:INET6, :DGRAM)
-  end
+guard -> { SocketSpecs.ipv6_available? } do
+  describe 'Socket#ipv6only!' do
+    before do
+      @socket = Socket.new(:INET6, :DGRAM)
+    end
 
-  after do
-    @socket.close
-  end
+    after do
+      @socket.close
+    end
 
-  it 'enables IPv6 only mode' do
-    @socket.ipv6only!
+    it 'enables IPv6 only mode' do
+      @socket.ipv6only!
 
-    @socket.getsockopt(:IPV6, :V6ONLY).bool.should == true
+      @socket.getsockopt(:IPV6, :V6ONLY).bool.should == true
+    end
   end
 end

test/socket/test_udp.rb

@@ -20,9 +20,13 @@ class TestSocket_UDPSocket < Test::Unit::TestCase
       assert_match(/AF_INET\b/, sock.inspect)
     }
     if Socket.const_defined?(:AF_INET6)
-      UDPSocket.open(Socket::AF_INET6) {|sock|
-        assert_match(/AF_INET6\b/, sock.inspect)
-      }
+      begin
+        UDPSocket.open(Socket::AF_INET6) {|sock|
+          assert_match(/AF_INET6\b/, sock.inspect)
+        }
+      rescue Errno::EAFNOSUPPORT
+        skip 'AF_INET6 not supported by kernel'
+      end
     end
   end