[PATCH 5/7] [gdb/testsuite] Fix Term::_csi_m with no args

[Tom de Vries <tdevries@suse.de>]

When calling Term::_csi_m with no args, default behaviour needs to be applied,
which is equivalent to "Term::_csi_m 0" [1].

However, while "Term::_csi_m 0" works, as well as 'Term::_csi_m ""', calling
Term::_csi_m with no args has no effect.

Fix this by implementing the default behaviour in Term::_csi_m.

Tested on aarch64-linux.

[1] https://vt100.net/docs/vt510-rm/SGR.html
---
 gdb/testsuite/gdb.tui/tuiterm.exp | 9 +++++++++
 gdb/testsuite/lib/tuiterm.exp     | 5 +++++
 2 files changed, 14 insertions(+)

diff --git a/gdb/testsuite/gdb.tui/tuiterm.exp b/gdb/testsuite/gdb.tui/tuiterm.exp
index e58de688ef2..6cd65f3ede7 100644
--- a/gdb/testsuite/gdb.tui/tuiterm.exp
+++ b/gdb/testsuite/gdb.tui/tuiterm.exp
@@ -783,6 +783,15 @@ proc test_attrs {} {
 	set line [Term::get_line_with_attrs 0]
 	gdb_assert { [regexp $re $line] } "attribute: $attr"
     }
+
+    # Regression test: Check that _csi_m works without arguments.
+    setup_terminal 4 1
+    Term::_csi_m 7
+    Term::_insert "a"
+    Term::_csi_m
+    Term::_insert "a"
+    set line [Term::get_line_with_attrs 0]
+    gdb_assert { [string equal $line "<reverse:1>a<reverse:0>a  "] }
 }
 
 # Run proc TEST_PROC_NAME with a "small" terminal.
diff --git a/gdb/testsuite/lib/tuiterm.exp b/gdb/testsuite/lib/tuiterm.exp
index 451fccc6693..10c5a3d0dce 100644
--- a/gdb/testsuite/lib/tuiterm.exp
+++ b/gdb/testsuite/lib/tuiterm.exp
@@ -638,6 +638,11 @@ namespace eval Term {
     #
     # https://vt100.net/docs/vt510-rm/SGR.html
     proc _csi_m {args} {
+	if { [llength $args] == 0 } {
+	    # Apply default.
+	    set args { 0 }
+	}
+
 	_log_cur "Select Graphic Rendition ([join $args {, }])" {
 	    variable _attrs
 
-- 
2.43.0