parameterize DNSResolver on the lookup TXT function

dns.go

@@ -11,7 +11,6 @@ import (
 	path "github.com/ipfs/go-path"
 	opts "github.com/ipfs/interface-go-ipfs-core/options/namesys"
 	isd "github.com/jbenet/go-is-domain"
-	madns "github.com/multiformats/go-multiaddr-dns"
 )
 
 const ethTLD = "eth"
@@ -28,8 +27,8 @@ type DNSResolver struct {
 }
 
 // NewDNSResolver constructs a name resolver using DNS TXT records.
-func NewDNSResolver(rslv madns.BasicResolver) *DNSResolver {
-	return &DNSResolver{lookupTXT: rslv.LookupTXT}
+func NewDNSResolver(lookup LookupTXTFunc) *DNSResolver {
+	return &DNSResolver{lookupTXT: lookup}
 }
 
 // Resolve implements Resolver.

namesys.go

@@ -74,7 +74,7 @@ func NewNameSystem(r routing.ValueStore, ds ds.Datastore, rslv madns.BasicResolv
 	}
 
 	return &mpns{
-		dnsResolver:      NewDNSResolver(rslv),
+		dnsResolver:      NewDNSResolver(rslv.LookupTXT),
 		proquintResolver: new(ProquintResolver),
 		ipnsResolver:     NewIpnsResolver(r),
 		ipnsPublisher:    NewIpnsPublisher(r, ds),