add tests for the extract() method to vcl_regex.vtc

src/tests/vcl_regex.vtc

@@ -106,7 +106,7 @@ varnish v1 -vcl {
 
 client c1 -run
 
-# sub() function
+# sub() method
 
 varnish v1 -vcl {
 	import re2 from "${vmod_topbuild}/src/.libs/libvmod_re2.so";
@@ -164,7 +164,7 @@ client c2 {
 	expect resp.http.regsuballsub == "barbazbar"
 } -run
 
-# suball() function
+# suball() method
 
 varnish v1 -vcl {
 	import re2 from "${vmod_topbuild}/src/.libs/libvmod_re2.so";
@@ -213,3 +213,53 @@ varnish v1 -vcl {
 }
 
 client c2 -run
+
+# extract() method
+
+varnish v1 -vcl {
+	import re2 from "${vmod_topbuild}/src/.libs/libvmod_re2.so";
+	backend b { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new barbaz = re2.regex("(bar)baz");
+	}
+
+	sub vcl_recv {
+		return(synth(200));
+	}
+
+	sub vcl_synth {
+		set resp.http.foo = "barbaz";
+		if (!barbaz.match(resp.http.foo)) {
+		        set resp.status = 999;
+		}
+
+		if (resp.http.foo ~ "bar(baz)") {
+			set resp.http.tilde =
+				barbaz.extract(resp.http.foo, "\0\1",
+			                       "tildesub");
+		} else {
+			set resp.status = 999;
+		}
+
+		if (resp.http.foo !~ "bar(quux)") {
+			set resp.http.neg =
+				barbaz.extract(resp.http.foo, "\0\1", "negsub");
+		} else {
+			set resp.status = 999;
+		}
+
+		set resp.http.regsub
+		    = regsub(resp.http.foo, "bar(baz)", "\1");
+		set resp.http.regsubsub = barbaz.extract(resp.http.foo, "\0\1",
+                                                         "regsubx");
+
+		set resp.http.regsuball
+		    = regsuball(resp.http.foo, "(.)", "x");
+		set resp.http.regsuballsub = barbaz.extract(resp.http.foo,
+		                                            "\0\1",
+                                                            "regsuballx");
+	}
+}
+
+client c2 -run