"pesi" should be prepended, not appended, to existing resp.filters.

src/tests/e00000.vtc

@@ -20,7 +20,7 @@ varnish v1 -arg "-p debug=+syncvsl" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00001.vtc

@@ -25,7 +25,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00002.vtc

@@ -24,7 +24,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00003.vtc

@@ -53,7 +53,7 @@ varnish v1 -arg "-p debug=+syncvsl" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00004.vtc

@@ -30,7 +30,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00005.vtc

@@ -31,7 +31,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00006.vtc

@@ -40,7 +40,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00007.vtc

@@ -43,7 +43,7 @@ varnish v1 -arg "-sdefault,2m" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00008.vtc

@@ -89,7 +89,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00009.vtc

@@ -29,7 +29,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00010.vtc

@@ -23,7 +23,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start -cli "param.set feature +esi_ignore_other_elements"

src/tests/e00011.vtc

@@ -28,7 +28,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00012.vtc

@@ -30,7 +30,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00013.vtc

@@ -20,7 +20,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00014.vtc

@@ -21,7 +21,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00015.vtc

@@ -40,7 +40,7 @@ varnish v1 -syntax 4.0 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		elsif (req.url != "/") {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start
@@ -83,7 +83,7 @@ varnish v1 -syntax 4.1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		elsif (req.url != "/top2") {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 	sub vcl_backend_response {

src/tests/e00016.vtc

@@ -70,14 +70,14 @@ varnish v1 \
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		elsif (req.url != "/body") {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 */
 		if (resp.filters ~ "\besi\b") {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00017.vtc

@@ -208,7 +208,7 @@ varnish v1 -arg "-p thread_pool_min=100" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00018.vtc

@@ -80,7 +80,7 @@ varnish v1 -arg "-p thread_pool_min=100" -arg "-p debug=+syncvsl,+processors" -v
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00019.vtc

@@ -58,7 +58,7 @@ varnish v1 -arg "-p thread_pool_min=100" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00020.vtc

@@ -26,7 +26,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00021.vtc

@@ -29,7 +29,7 @@ varnish v1 -syntax 4.0 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00022.vtc

@@ -29,7 +29,7 @@ varnish v1 -syntax 4.0 -arg "-p thread_pool_stack=262144" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00025.vtc

@@ -14,7 +14,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00027.vtc

@@ -19,7 +19,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/e00028.vtc

@@ -53,7 +53,7 @@ varnish v1 -arg "-p feature=+esi_disable_xml_check" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/pesi.vtc

@@ -25,7 +25,7 @@ varnish v1 -arg "-p debug=+waitinglist" -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start

src/tests/uncacheable.vtc

@@ -92,7 +92,7 @@ varnish v1 -vcl+backend {
 		   set resp.filters = regsub(resp.filters, "\besi\b", "pesi");
 		}
 		else {
-		   set resp.filters = resp.filters + " pesi";
+		   set resp.filters = "pesi " + resp.filters;
 		}
 	}
 } -start