Test the set-salt error.

src/tests/encrypt.vtc

@@ -12,7 +12,7 @@ varnishtest "standard encryption VFP"
 # random salt is generated.
 feature cmd {test $ENABLE_SET_SALT = "yes"}
 
-server s1 {
+server s1 -repeat 2 {
 	rxreq
 	txresp -body {I am the walrus}
 } -start
@@ -32,6 +32,7 @@ varnish v1 -arg "-p vsl_mask=+VfpAcct" -vcl+backend {
 		set bereq.http.X-ECE-Key-ID = "";
 		set bereq.http.XYZZY-ECE-Salt = "I1BsxtFttlv3u/Oo94xnmw==";
 		set beresp.filters = "ece_encrypt";
+		set beresp.uncacheable = true;
 	}
 } -start
 
@@ -58,3 +59,29 @@ logexpect l1 -v v1 -d 1 -g vxid -q "VfpAcct" {
 	expect * = VfpAcct	{^ece_encrypt \d+ 53$}
 	expect * = End
 } -run
+
+# set-salt error
+varnish v1 -vcl+backend {
+	import ${vmod_ece};
+
+	sub vcl_backend_response {
+		set bereq.http.X-ECE-Key-ID = "";
+		set bereq.http.XYZZY-ECE-Salt = "foobar";
+		set beresp.filters = "ece_encrypt";
+	}
+}
+
+logexpect l1 -v v1 -d 0 -g vxid -q "FetchError" {
+	expect 0 * Begin	bereq
+	expect * = FetchError	{^set-salt base64 decoding error$}
+	expect * = End
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 503
+	expect resp.reason == "Backend fetch failed"
+} -run
+
+logexpect l1 -wait