patch 8.1.1302: v:beval_text is not tested in Visual mode

Problem:    v:beval_text is not tested in Visual mode.
Solution:   Add a screenshot of the balloon in Visual mode.
diff --git a/src/testdir/test_balloon.vim b/src/testdir/test_balloon.vim
index e518755..966587c 100644
--- a/src/testdir/test_balloon.vim
+++ b/src/testdir/test_balloon.vim
@@ -9,19 +9,24 @@
   finish
 endif
 
-func Test_balloon_eval_term()
-  call writefile([
+let s:common_script = [
 	\ 'call setline(1, ["one one one", "two tXo two", "three three three"])',
 	\ 'set balloonevalterm balloonexpr=MyBalloonExpr() balloondelay=100',
 	\ 'func MyBalloonExpr()',
-	\ ' return "line " . v:beval_lnum . " column " . v:beval_col',
+	\ ' return "line " .. v:beval_lnum .. " column " .. v:beval_col .. ": " .. v:beval_text',
 	\ 'endfun',
 	\ 'redraw',
+	\ ]
+
+func Test_balloon_eval_term()
+  " Use <Ignore> after <MouseMove> to return from vgetc() without removing
+  " the balloon.
+  call writefile(s:common_script + [
 	\ 'call test_setmouse(2, 6)',
 	\ 'call feedkeys("\<MouseMove>\<Ignore>", "xt")',
 	\ ], 'XTest_beval')
 
-  " Check that the balloon shows up
+  " Check that the balloon shows up after a mouse move
   let buf = RunVimInTerminal('-S XTest_beval', {'rows': 10, 'cols': 50})
   call term_wait(buf, 100)
   call VerifyScreenDump(buf, 'Test_balloon_eval_term_01', {})
@@ -30,3 +35,21 @@
   call StopVimInTerminal(buf)
   call delete('XTest_beval')
 endfunc
+
+func Test_balloon_eval_term_visual()
+  " Use <Ignore> after <MouseMove> to return from vgetc() without removing
+  " the balloon.
+  call writefile(s:common_script + [
+	\ 'call test_setmouse(3, 6)',
+	\ 'call feedkeys("3Gevfr\<MouseMove>\<Ignore>", "xt")',
+	\ ], 'XTest_beval_visual')
+
+  " Check that the balloon shows up after a mouse move
+  let buf = RunVimInTerminal('-S XTest_beval_visual', {'rows': 10, 'cols': 50})
+  call term_wait(buf, 100)
+  call VerifyScreenDump(buf, 'Test_balloon_eval_term_02', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('XTest_beval_visual')
+endfunc