[gdb/testsuite] Fix and add prompt anchoring in tuiterm

There is a test-case that contains a unit test for tuiterm:
gdb.tui/tuiterm.exp.

However, this only excercises the tuiterm itself, and not the functions that
interact with it, like Term::command.

Add a new test-case gdb.tui/tuiterm-2.exp that:
- overrides proc accept_gdb_output (to be able simulate incorrect responses
  while avoiding the timeout),
- overrides proc send_gdb (to be able to call Term::command without a gdb
  instance, such that all tuiterm input is generated by the test-case).
- issues Term::command calls, and
- checks whether they behave correctly.

This exposes a problem in Term::command.  The "prompt before command" regexp
starts with a bit that is supposed to anchor the prompt to the border:
...
	set str "(^|\|)$gdb_prompt $str"
...
but that doesn't work due to insufficient escaping.  Fix this by adding the
missing escape:
...
	set str "(^|\\|)$gdb_prompt $str"
...

Futhermore, the "prompt after command" regexp in Term::wait_for has no
anchoring at all:
...
	set prompt_wait_for "$gdb_prompt \$"
...
so add that as well.

Tested on x86_64-linux.

2 files changed, 100 insertions, 2 deletions

diff --git a/gdb/testsuite/gdb.tui/tuiterm-2.exp b/gdb/testsuite/gdb.tui/tuiterm-2.exp
new file mode 100644
index 0000000..e7a0f03
--- /dev/null
+++ b/gdb/testsuite/gdb.tui/tuiterm-2.exp
@@ -0,0 +1,98 @@
+# Copyright 2023 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Check tuiterm procs that interact with gdb as well as tuiterm.
+
+tuiterm_env
+
+proc test_accept_gdb_output { } {
+    if { $::action_cnt == [llength $::actions] } {
+	return 0
+    }
+    set action [lindex $::actions $::action_cnt]
+    incr ::action_cnt
+
+    uplevel $action
+
+    return 1
+}
+
+proc test_send_gdb { string } {
+    set expected [lindex $::expect_send $::send_cnt]
+    gdb_assert { [string equal $string $expected] }
+
+    incr ::send_cnt
+}
+
+with_override Term::accept_gdb_output test_accept_gdb_output {
+    with_override send_gdb test_send_gdb {
+
+	foreach_with_prefix border { "" "|" } {
+	    with_test_prefix "Term::command match" {
+		Term::_setup 4 20
+		set send_cnt 0
+		set expect_send { foo\n }
+		set action_cnt 0
+		set actions {
+		    {
+			Term::_insert "${::border}(gdb) foo"
+		    }
+		    {
+			Term::_ctl_0x0d
+			Term::_ctl_0x0a
+			Term::_insert "${::border}(gdb) "
+		    }
+		}
+		gdb_assert { [Term::command "foo"] }
+	    }
+
+	    with_test_prefix "Term::command mismatch" {
+		Term::_setup 4 20
+		set send_cnt 0
+		set expect_send { foo\n }
+		set action_cnt 0
+		set actions {
+		    {
+			Term::_insert "$::border (gdb) foo"
+		    }
+		    {
+			Term::_ctl_0x0d
+			Term::_ctl_0x0a
+			Term::_insert "${::border}(gdb) "
+		    }
+		}
+		gdb_assert { ![Term::command "foo"] }
+	    }
+
+	    with_test_prefix "Term::command mismatch 2" {
+		Term::_setup 4 20
+		set send_cnt 0
+		set expect_send { foo\n }
+		set action_cnt 0
+		set actions {
+		    {
+			Term::_insert "${::border}(gdb) foo"
+		    }
+		    {
+			Term::_ctl_0x0d
+			Term::_ctl_0x0a
+			Term::_insert "${::border} (gdb) "
+		    }
+		}
+		gdb_assert { ![Term::command "foo"] }
+	    }
+	}
+    }
+}
diff --git a/gdb/testsuite/lib/tuiterm.exp b/gdb/testsuite/lib/tuiterm.exp
index 171b242..dc928ae 100644
--- a/gdb/testsuite/lib/tuiterm.exp
+++ b/gdb/testsuite/lib/tuiterm.exp
@@ -788,7 +788,7 @@ namespace eval Term {
 
 	set fn "wait_for"
 
-	set prompt_wait_for "$gdb_prompt \$"
+	set prompt_wait_for "(^|\\|)$gdb_prompt \$"
 	debug_tui_matching "$fn: regexp: '$wait_for'"
 
 	while 1 {
@@ -909,7 +909,7 @@ namespace eval Term {
 	global gdb_prompt
 	send_gdb "$cmd\n"
 	set str [string_to_regexp $cmd]
-	set str "(^|\|)$gdb_prompt $str"
+	set str "(^|\\|)$gdb_prompt $str"
 	wait_for $str
     }