patch 9.0.1779: Need more state() tests

Problem:  Need more state() tests
Solution: Add a few more tests for operater pending mode and register
          yank command

closes: #12883

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: author
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index a500b73..0eda5de 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -2901,6 +2901,20 @@
   call term_sendkeys(buf, getstate)
   call WaitForAssert({-> assert_match('state: mSc; mode: n', term_getline(buf, 6))}, 1000)
 
+  " A operator is pending
+  call term_sendkeys(buf, ":call RunTimer()\<CR>y")
+  call TermWait(buf, 25)
+  call term_sendkeys(buf, "y")
+  call term_sendkeys(buf, getstate)
+  call WaitForAssert({-> assert_match('state: oSc; mode: n', term_getline(buf, 6))}, 1000)
+
+  " A register was specified
+  call term_sendkeys(buf, ":call RunTimer()\<CR>\"r")
+  call TermWait(buf, 25)
+  call term_sendkeys(buf, "yy")
+  call term_sendkeys(buf, getstate)
+  call WaitForAssert({-> assert_match('state: oSc; mode: n', term_getline(buf, 6))}, 1000)
+
   " Insert mode completion (bit slower on Mac)
   call term_sendkeys(buf, ":call RunTimer()\<CR>Got\<C-N>")
   call TermWait(buf, 25)