Working on adding pager.

tests/test_terminal.py

@@ -308,4 +308,26 @@ def test_open_browser(terminal):
         terminal.open_browser(url)
     open_new_tab.assert_called_with(url)
     assert curses.endwin.called
-    assert curses.doupdate.called
+    assert curses.doupdate.called
+
+
+def test_open_pager(terminal, stdscr):
+
+    data = "Hello World!"
+
+    def side_effect(*_, stdin=None):
+        assert stdin is not None
+        raise OSError
+
+    with mock.patch('subprocess.Popen', autospec=True) as Popen, \
+            mock.patch.dict('os.environ', {'PAGER': 'fake'}):
+
+        terminal.open_pager(data)
+        assert Popen.called
+        assert not stdscr.addstr.called
+
+        # Raise an OS error
+        Popen.side_effect = side_effect
+        terminal.open_pager(data)
+        message = 'Could not open pager fake'.encode('ascii')
+        assert stdscr.addstr.called_with(0, 0, message)