patch 8.1.2137: parsing the termresponse is not tested

Problem:    Parsing the termresponse is not tested.
Solution:   Add a first test. (related to #5042)

src/testdir/test_termcodes.vim

@@ -779,9 +779,9 @@ func Test_term_rgb_response()
 endfunc
 
 " This only checks if the sequence is recognized.
-" This must be last, because it has side effects to xterm properties.
+" This must be after other tests, because it has side effects to xterm
-" TODO: check that the values were parsed properly
+" properties.
-func Test_xx_term_style_response()
+func Test_xx01_term_style_response()
   " Termresponse is only parsed when t_RV is not empty.
   set t_RV=x
 
@@ -797,6 +797,24 @@ func Test_xx_term_style_response()
   set t_RV=
 endfunc
 
+" This checks the libvterm version response.
+" This must be after other tests, because it has side effects to xterm
+" properties.
+" TODO: check other terminals response
+func Test_xx02_libvterm_response()
+  " Termresponse is only parsed when t_RV is not empty.
+  set t_RV=x
+  set ttymouse=xterm
+  call test_option_not_set('ttymouse')
+
+  let seq = "\<Esc>[>0;100;0c"
+  call feedkeys(seq, 'Lx!')
+  call assert_equal(seq, v:termresponse)
+  call assert_equal('sgr', &ttymouse)
+
+  set t_RV=
+endfunc
+
 func Test_get_termcode()
   try
     let k1 = &t_k1

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2137,
 /**/
     2136,
 /**/