better test coverage for changing the uncacheable_direct argument

src/vtc/lazy.vtc

@@ -21,17 +21,20 @@ varnish v1 -vcl+backend {
 	new rr = directors.round_robin();
 	rr.add_backend(s1);
 	rr.add_backend(s2);
-	new cl = cluster.cluster(rr.backend(), deny=s2, real=s3,
-	    uncacheable_direct=false);
+	new cl = cluster.cluster(rr.backend(), deny=s2, real=s3);
     }
     sub vcl_recv {
 	return (pass);
     }
     sub vcl_backend_fetch {
-	set bereq.backend = cl.backend();
+	set bereq.http.unc1 = cl.get_uncacheable_direct();
+	set bereq.backend = cl.backend(uncacheable_direct=false);
+	set bereq.http.unc2 = cl.get_uncacheable_direct();
     }
     sub vcl_backend_response {
+	set beresp.http.unc1 = bereq.http.unc1;
 	set beresp.http.backend = beresp.backend;
+	set beresp.http.unc2 = bereq.http.unc2;
     }
 } -start
 
@@ -39,9 +42,13 @@ client c1 {
 	txreq
 	rxresp
 	expect resp.status == 200
+	expect resp.http.unc1 == "true"
 	expect resp.http.backend == "s1"
+	expect resp.http.unc2 == "false"
 	txreq
 	rxresp
 	expect resp.status == 200
+	expect resp.http.unc1 == "true"
 	expect resp.http.backend == "s3"
+	expect resp.http.unc2 == "false"
 } -run