[binutils-gdb] gdb/testsuite: address test failures in gdb.mi/mi-multi-commands.exp

[binutils-gdb] gdb/testsuite: address test failures in gdb.mi/mi-multi-commands.exp

[Andrew Burgess]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b24ae11cd432684feb5ed73f215a36ac89023085

commit b24ae11cd432684feb5ed73f215a36ac89023085
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Tue Mar 22 10:23:26 2022 +0000

    gdb/testsuite: address test failures in gdb.mi/mi-multi-commands.exp
    
    The gdb.mi/mi-multi-commands.exp test was added in commit:
    
      commit d08cbc5d3203118da5583296e49273cf82378042
      Date:   Wed Dec 22 12:57:44 2021 +0000
    
          gdb: unbuffer all input streams when not using readline
    
    And then tweaked in commit:
    
      commit 144459531dd68a1287905079aaa131b777a8cc82
      Date:   Mon Feb 7 20:35:58 2022 +0000
    
          gdb/testsuite: relax pattern in new gdb.mi/mi-multi-commands.exp test
    
    The second of these commits was intended to address periodic test
    failures that I was seeing, and this change did fix some problems,
    but, unfortunately, introduced other issues.
    
    The problem is that the test relies on sending two commands to GDB in
    a single write.  As the characters that make these two commands arrive
    they are echoed to GDB's console.  However, there is a race between
    how quickly the characters are echoed and how quickly GDB decides to
    act on the incoming commands.
    
    Usually, both commands are echoed in full before GDB acts on the first
    command, but sometimes this is not the case, and GDB can execute the
    first command before both commands are fully echoed to the console.
    In this case, the output of the first command will be mixed in with
    the echoing of the second command.
    
    This mixing of the command echoing and the first command output is
    what was causing failures in the original version of the test.
    
    The second commit relaxed the expected output pattern a little, but
    was still susceptible to failures, so this commit further relaxes the
    pattern.
    
    Now, we look for the first command output with no regard to what is
    before, or after the command.  Then we look for the first mi prompt to
    indicate that the first command has completed.
    
    I believe that this change should make the test more stable than it
    was before.

Diff:
---
 gdb/testsuite/gdb.mi/mi-multi-commands.exp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/gdb/testsuite/gdb.mi/mi-multi-commands.exp b/gdb/testsuite/gdb.mi/mi-multi-commands.exp
index 12b1b482f9a..d00e0aaea8b 100644
--- a/gdb/testsuite/gdb.mi/mi-multi-commands.exp
+++ b/gdb/testsuite/gdb.mi/mi-multi-commands.exp
@@ -100,9 +100,12 @@ proc run_test { args } {
 	set seen_second_message false
 
 	gdb_test_multiple "" "look for first command output, command length $i" -prompt "$mi_gdb_prompt" {
-	    -re "\\^done,value=\"\\\\\"FIRST COMMAND\\\\\"\"\r\n" {
-		pass $gdb_test_name
+	    -re "\\^done,value=\"\\\\\"FIRST COMMAND\\\\\"\"" {
 		set seen_first_message true
+		exp_continue
+	    }
+	    -re "\r\n$mi_gdb_prompt" {
+		gdb_assert $seen_first_message $gdb_test_name
 	    }
 	}