add function version() and some fundamental tests

src/tests/a01.vtc

@@ -17,4 +17,3 @@ client c1 {
 	expect resp.status == 200
 	expect resp.http.foo == 1
 } -run
-

src/tests/a02.vtc

+# Somewhat oversimplified, but at least it ensures that SOMETHING works
+# (The alternative would be to automakeify this test or manually update it
+# every time there's a new version, which defeats the purpose somewhat).
+
+varnishtest "vtstor-vmod: Test version string"
+
+server s1 {
+	rxreq
+	expect req.url == "/"
+	txresp -status 200
+} -start
+
+varnish v1 -vcl+backend {
+	import vtstor from "${vmod_topbuild}/src/.libs/libvmod_vtstor.so";
+
+	sub vcl_backend_response {
+		set beresp.http.x-version = vtstor.version();
+		if (!beresp.http.x-version) {
+			set beresp.status = 500;
+		}
+		return(deliver);
+	}
+} -start
+
+client c1 {
+	txreq -url "/"
+	rxresp
+	expect resp.status == 200
+} -run

src/tests/a03.vtc

+varnishtest "vtstor-vmod: vcl.use and .discard"
+
+server s1 {
+} -start
+
+varnish v1 -vcl+backend {
+	import vtstor from "${vmod_topbuild}/src/.libs/libvmod_vtstor.so";
+} -start
+
+varnish v1 -vcl+backend {
+} 
+
+varnish v1 -cli "vcl.list"
+varnish v1 -cli "vcl.use vcl1"
+
+varnish v1 -cli "vcl.use vcl2"
+varnish v1 -cli "vcl.use vcl1"
+
+varnish v1 -cli "vcl.show vcl1"
+varnish v1 -cli "vcl.use vcl2"
+varnish v1 -cli "vcl.discard vcl1"
+varnish v1 -cli "vcl.list"

src/vmod_vtstor.c

@@ -170,3 +170,10 @@ vmod_vxid(VRT_CTX, struct vmod_priv *priv)
 	return(priv->priv);
 }
 #endif
+
+VCL_STRING  __match_proto__(td_vmod_version)
+vmod_version(VRT_CTX)
+{
+        return VERSION;
+}
+

src/vmod_vtstor.vcc

@@ -34,3 +34,5 @@ $Method STRING .get(HEADER)
 $Method VOID .delete(HEADER)
 
 # $Function STRING vxid(PRIV_TASK)
+
+$Function STRING version()