Обсуждение: [HACKERS] bug/oversight in TestLib.pm and PostgresNode.pm

I am trying to re-create pgbench-over-logical-replication as a TAP-test. 
(the wisdom of that might be doubted, and I appreciate comments on it 
too, but it's really another subject).

While trying to test pgbench's stderr (looking for 'creating tables' in 
output of the initialisation step)  I ran into these two bugs (or 
perhaps better 'oversights').

But especially the omission of command_fails_like() in PostgresNode.pm 
feels like an bug.

In the end it was necessary to change TestLib.pm's command_like() 
because command_fails_like() also checks for a non-zero return value 
(which seems to make sense, but in this case not possible: pgbench 
returns 0 on init with output on stderr).


make check-world passes without error


Thanks,

Erik Rijkers


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On Thu, Mar 23, 2017 at 12:51 AM, Erik Rijkers <er@xs4all.nl> wrote:
> While trying to test pgbench's stderr (looking for 'creating tables' in
> output of the initialisation step)  I ran into these two bugs (or perhaps
> better 'oversights').

+   if (defined $expected_stderr) {
+       like($stderr, $expected_stderr, "$test_name: stderr matches");
+   }
+   else {   is($stderr, '', "$test_name: no stderr");
-   like($stdout, $expected_stdout, "$test_name: matches");
+   }
To simplify that you could as well set expected_output to be an empty
string, and just use like() instead of is(), saving this if/else.

> But especially the omission of command_fails_like() in PostgresNode.pm feels
> like an bug.

+=item $node->command_fails_like(...) - TestLib::command_fails_like
with our PGPORT
+
+See command_ok(...)
+
+=cut
+
+sub command_fails_like
+{
+   my $self = shift;
+
+   local $ENV{PGPORT} = $self->port;
+
+   TestLib::command_fails_like(@_);
+}
Most likely a case where this is needed has not showed up, so +1 to
remove this inconsistency across the modules.
-- 
Michael

On 2017-03-23 03:28, Michael Paquier wrote:
> On Thu, Mar 23, 2017 at 12:51 AM, Erik Rijkers <er@xs4all.nl> wrote:
>> While trying to test pgbench's stderr (looking for 'creating tables' 
>> in
>> output of the initialisation step)  I ran into these two bugs (or 
>> perhaps
>> better 'oversights').
> 
> +   if (defined $expected_stderr) {
> +       like($stderr, $expected_stderr, "$test_name: stderr matches");
> +   }
> +   else {
>     is($stderr, '', "$test_name: no stderr");
> -   like($stdout, $expected_stdout, "$test_name: matches");
> +   }
> To simplify that you could as well set expected_output to be an empty
> string, and just use like() instead of is(), saving this if/else.

(I'll assume you meant '$expected_stderr' (not 'expected_output'))

That would be nice but with that, other tests start complaining: 
"doesn't look like a regex to me"

To avoid that, I uglified your version back to:

+       like($stderr, (defined $expected_stderr ? $expected_stderr : 
qr{}),
+                                       "$test_name: stderr matches");

I did it like that in the attached patch 
(0001-testlib-like-stderr.diff).


The other (PostgresNode.pm.diff) is unchanged.

make check-world without error.


Thanks,

Erik Rijkers


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On 3/22/17 11:51, Erik Rijkers wrote:
> While trying to test pgbench's stderr (looking for 'creating tables' in 
> output of the initialisation step)  I ran into these two bugs (or 
> perhaps better 'oversights').

Perhaps pgbench should be printing progress messages to stdout instead?

> But especially the omission of command_fails_like() in PostgresNode.pm 
> feels like an bug.

Yeah, that's just because no one has needed it yet.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services