Remove the word middleware (#1067)

* Rename middleware to plugin

first pass; mostly used 'sed', few spots where I manually changed
text.

This still builds a coredns binary.

* fmt error

* Rename AddMiddleware to AddPlugin

* Readd AddMiddleware to remain backwards compat

plugin/federation/federation_test.go

@@ -0,0 +1,81 @@
+package federation
+
+import (
+	"testing"
+
+	"github.com/coredns/coredns/plugin/kubernetes"
+	"github.com/coredns/coredns/plugin/pkg/dnsrecorder"
+	"github.com/coredns/coredns/plugin/test"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+func TestIsNameFederation(t *testing.T) {
+	tests := []struct {
+		fed          string
+		qname        string
+		expectedZone string
+	}{
+		{"prod", "nginx.mynamespace.prod.svc.example.com.", "nginx.mynamespace.svc.example.com."},
+		{"prod", "nginx.mynamespace.staging.svc.example.com.", ""},
+		{"prod", "nginx.mynamespace.example.com.", ""},
+		{"prod", "example.com.", ""},
+		{"prod", "com.", ""},
+	}
+
+	fed := New()
+	for i, tc := range tests {
+		fed.f[tc.fed] = "test-name"
+		if x, _ := fed.isNameFederation(tc.qname, "example.com."); x != tc.expectedZone {
+			t.Errorf("Test %d, failed to get zone, expected %s, got %s", i, tc.expectedZone, x)
+		}
+	}
+}
+
+func TestFederationKubernetes(t *testing.T) {
+	tests := []test.Case{
+		{
+			// service exists so we return the IP address associated with it.
+			Qname: "svc1.testns.prod.svc.cluster.local.", Qtype: dns.TypeA,
+			Rcode: dns.RcodeSuccess,
+			Answer: []dns.RR{
+				test.A("svc1.testns.prod.svc.cluster.local.      303       IN      A       10.0.0.1"),
+			},
+		},
+		{
+			// service does not exist, do the federation dance.
+			Qname: "svc0.testns.prod.svc.cluster.local.", Qtype: dns.TypeA,
+			Rcode: dns.RcodeSuccess,
+			Answer: []dns.RR{
+				test.CNAME("svc0.testns.prod.svc.cluster.local.  303       IN      CNAME   svc0.testns.prod.svc.fd-az.fd-r.federal.example."),
+			},
+		},
+	}
+
+	k := kubernetes.New([]string{"cluster.local."})
+	k.APIConn = &APIConnFederationTest{}
+
+	fed := New()
+	fed.zones = []string{"cluster.local."}
+	fed.Federations = k.Federations
+	fed.Next = k
+	fed.f = map[string]string{
+		"prod": "federal.example.",
+	}
+
+	ctx := context.TODO()
+	for i, tc := range tests {
+		m := tc.Msg()
+
+		rec := dnsrecorder.New(&test.ResponseWriter{})
+		_, err := fed.ServeDNS(ctx, rec, m)
+		if err != nil {
+			t.Errorf("Test %d, expected no error, got %v\n", i, err)
+			return
+		}
+
+		resp := rec.Msg
+		test.SortAndCheck(t, resp, tc)
+	}
+}