[master] dca6658ae varnishtest: Introduce a ${varnishd_args} macro

[Dridi Boukelmoune]

commit dca6658ae75fd7dbca6e0696a3f554c0f74aced0
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Fri Apr 14 15:29:11 2023 +0200

    varnishtest: Introduce a ${varnishd_args} macro
    
    Refs #3897

diff --git a/bin/varnishtest/vtc_varnish.c b/bin/varnishtest/vtc_varnish.c
index f763fcce7..c8b6bba15 100644
--- a/bin/varnishtest/vtc_varnish.c
+++ b/bin/varnishtest/vtc_varnish.c
@@ -430,6 +430,10 @@ varnish_launch(struct varnish *v)
 	if (vmod_path != NULL)
 		VSB_printf(vsb, " -p vmod_path=%s", vmod_path);
 	VSB_printf(vsb, " %s", VSB_data(v->args));
+	if (macro_isdef(NULL, "varnishd_args")) {
+		VSB_putc(vsb, ' ');
+		macro_cat(v->vl, vsb, "varnishd_args", NULL);
+	}
 	AZ(VSB_finish(vsb));
 	vtc_log(v->vl, 3, "CMD: %s", VSB_data(vsb));
 	vsb1 = macro_expand(v->vl, VSB_data(vsb));
@@ -1068,6 +1072,12 @@ vsl_catchup(struct varnish *v)
  * \-arg STRING
  *         Pass an argument to varnishd, for example "-h simple_list".
  *
+ *         If the ${varnishd_args} macro is defined, it is expanded and
+ *         appended to the varnishd command line, before the command line
+ *         itself is expanded. This enables tweaks to the varnishd command
+ *         line without editing test cases. This macro can be defined using
+ *         the ``-D`` option for varnishtest.
+ *
  * \-vcl STRING
  *         Specify the VCL to load on this Varnish instance. You'll probably
  *         want to use multi-lines strings for this ({...}).