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

1 files changed, 73 insertions, 0 deletions

diff --git a/plugin/errors/errors_test.go b/plugin/errors/errors_test.go
new file mode 100644
index 000000000..039562a56
--- /dev/null
+++ b/plugin/errors/errors_test.go
@@ -0,0 +1,73 @@
+package errors
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"log"
+	"strings"
+	"testing"
+
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/pkg/dnsrecorder"
+	"github.com/coredns/coredns/plugin/test"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+func TestErrors(t *testing.T) {
+	buf := bytes.Buffer{}
+	em := errorHandler{Log: log.New(&buf, "", 0)}
+
+	testErr := errors.New("test error")
+	tests := []struct {
+		next         plugin.Handler
+		expectedCode int
+		expectedLog  string
+		expectedErr  error
+	}{
+		{
+			next:         genErrorHandler(dns.RcodeSuccess, nil),
+			expectedCode: dns.RcodeSuccess,
+			expectedLog:  "",
+			expectedErr:  nil,
+		},
+		{
+			next:         genErrorHandler(dns.RcodeNotAuth, testErr),
+			expectedCode: dns.RcodeNotAuth,
+			expectedLog:  fmt.Sprintf("[ERROR %d %s] %v\n", dns.RcodeNotAuth, "example.org. A", testErr),
+			expectedErr:  testErr,
+		},
+	}
+
+	ctx := context.TODO()
+	req := new(dns.Msg)
+	req.SetQuestion("example.org.", dns.TypeA)
+
+	for i, tc := range tests {
+		em.Next = tc.next
+		buf.Reset()
+		rec := dnsrecorder.New(&test.ResponseWriter{})
+		code, err := em.ServeDNS(ctx, rec, req)
+
+		if err != tc.expectedErr {
+			t.Errorf("Test %d: Expected error %v, but got %v",
+				i, tc.expectedErr, err)
+		}
+		if code != tc.expectedCode {
+			t.Errorf("Test %d: Expected status code %d, but got %d",
+				i, tc.expectedCode, code)
+		}
+		if log := buf.String(); !strings.Contains(log, tc.expectedLog) {
+			t.Errorf("Test %d: Expected log %q, but got %q",
+				i, tc.expectedLog, log)
+		}
+	}
+}
+
+func genErrorHandler(rcode int, err error) plugin.Handler {
+	return plugin.HandlerFunc(func(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+		return rcode, err
+	})
+}