Don't run test which uses Kernel#fork on the Windows platform, where fork is not implemented.

spec/driver/selenium_driver_spec.rb

@@ -1,4 +1,5 @@
 require 'spec_helper'
+require 'rbconfig'
 
 describe Capybara::Selenium::Driver do
   before do
@@ -13,14 +14,16 @@ describe Capybara::Selenium::Driver do
   it_should_behave_like "driver without status code support"
   it_should_behave_like "driver with cookies support"
 
-  it "should not interfere with forking child processes" do
-    # Launch a browser, which registers the at_exit hook
-    browser = Capybara::Selenium::Driver.new(TestApp).browser
+  unless Config::CONFIG['host_os'] =~ /mswin|mingw/
+    it "should not interfere with forking child processes" do
+      # Launch a browser, which registers the at_exit hook
+      browser = Capybara::Selenium::Driver.new(TestApp).browser
 
-    # Fork an unrelated child process. This should not run the code in the at_exit hook.
-    pid = fork { "child" }
-    Process.wait2(pid)[1].exitstatus.should == 0
+      # Fork an unrelated child process. This should not run the code in the at_exit hook.
+      pid = fork { "child" }
+      Process.wait2(pid)[1].exitstatus.should == 0
 
-    browser.quit
+      browser.quit
+    end
   end
 end