test fixes

rich/console.py

@@ -557,7 +557,7 @@ class Console:
         Returns:
             str: Console output.
         """
-        render_result = self._render_buffer()
+        render_result = self._render_buffer(self._buffer)
         del self._buffer[:]
         self._exit_buffer()
         return render_result

rich/pager.py

@@ -14,7 +14,7 @@ class Pager(ABC):
         """
 
 
-class SystemPager:
+class SystemPager(Pager):
     """Uses the pager installed on the system."""
 
     def show(self, content: str) -> None:

rich/segment.py

@@ -312,7 +312,7 @@ class Segment(NamedTuple):
                 yield segment
             else:
                 text, style, _is_control = segment
-                yield cls(text, style.copy(link=None))
+                yield cls(text, style.copy(link=None) if style else None)
 
     @classmethod
     def strip_styles(cls, segments: Iterable["Segment"]) -> Iterable["Segment"]: