Calculate time using Process::CLOCK_MONOTONIC rather than Time.now

Some gems (Timecop in particular) mock Time class causing failures for
our timeout-like loops. With this change, we now use more low-level API
introduced in MRI 2.1 to get monotonic clock. This API gives a bit
different results on POSIX vs Windows, but consistent enough for our
needs. JRuby also supports this for years.

rb/lib/selenium/webdriver/common/socket_lock.rb

@@ -47,15 +47,19 @@ def locked
       private
 
       def lock
-        max_time = Time.now + @timeout
+        max_time = current_time + @timeout
 
-        sleep 0.1 until can_lock? || Time.now >= max_time
+        sleep 0.1 until can_lock? || current_time >= max_time
 
         return if did_lock?
 
         raise Error::WebDriverError, "unable to bind to locking port #{@port} within #{@timeout} seconds"
       end
 
+      def current_time
+        Process.clock_gettime(Process::CLOCK_MONOTONIC)
+      end
+
       def release
         @server&.close
       end

rb/lib/selenium/webdriver/common/socket_poller.rb

@@ -96,24 +96,19 @@ def conn_completed?(sock)
       end
 
       def with_timeout
-        max_time = time_now + @timeout
+        max_time = current_time + @timeout
 
-        (
+        until current_time > max_time
           return true if yield
 
-          wait
-        ) until time_now > max_time
+          sleep @interval
+        end
 
         false
       end
 
-      def wait
-        sleep @interval
-      end
-
-      # for testability
-      def time_now
-        Time.now
+      def current_time
+        Process.clock_gettime(Process::CLOCK_MONOTONIC)
       end
     end # SocketPoller
   end # WebDriver

rb/lib/selenium/webdriver/common/wait.rb

@@ -48,10 +48,10 @@ def initialize(opts = {})
       #
 
       def until
-        end_time = Time.now + @timeout
+        end_time = current_time + @timeout
         last_error = nil
 
-        until Time.now > end_time
+        until current_time > end_time
           begin
             result = yield
             return result if result
@@ -72,6 +72,12 @@ def until
 
         raise Error::TimeOutError, msg
       end
+
+      private
+
+      def current_time
+        Process.clock_gettime(Process::CLOCK_MONOTONIC)
+      end
     end # Wait
   end # WebDriver
 end # Selenium

rb/spec/unit/selenium/webdriver/socket_poller_spec.rb

@@ -46,7 +46,7 @@ def setup_connect(*states)
           wait  = Time.parse('2010-01-01 00:00:04')
           stop  = Time.parse('2010-01-01 00:00:06')
 
-          allow(Time).to receive(:now).and_return(start, wait, stop)
+          expect(Process).to receive(:clock_gettime).and_return(start, wait, stop)
           expect(poller).not_to be_connected
         end
       end
@@ -61,12 +61,11 @@ def setup_connect(*states)
         it 'returns false if the socket is still listening after the given timeout' do
           setup_connect true
 
-          start = Time.parse('2010-01-01 00:00:00')
-          wait  = Time.parse('2010-01-01 00:00:04')
-          stop  = Time.parse('2010-01-01 00:00:06')
+          start = Time.parse('2010-01-01 00:00:00').to_f
+          wait  = Time.parse('2010-01-01 00:00:04').to_f
+          stop  = Time.parse('2010-01-01 00:00:06').to_f
 
-          # on rbx, we can't add expectations to Time.now since it will be called by the kernel code.
-          allow(poller).to receive(:time_now).and_return(start, wait, stop)
+          expect(Process).to receive(:clock_gettime).and_return(start, wait, stop)
           expect(poller).not_to be_closed
         end
       end