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/file/setup_test.go

@@ -0,0 +1,77 @@
+package file
+
+import (
+	"testing"
+
+	"github.com/coredns/coredns/plugin/test"
+
+	"github.com/mholt/caddy"
+)
+
+func TestFileParse(t *testing.T) {
+	zoneFileName1, rm, err := test.TempFile(".", dbMiekNL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rm()
+
+	zoneFileName2, rm, err := test.TempFile(".", dbDnssexNLSigned)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rm()
+
+	tests := []struct {
+		inputFileRules string
+		shouldErr      bool
+		expectedZones  Zones
+	}{
+		{
+			`file ` + zoneFileName1 + ` miek.nl {
+				transfer from 127.0.0.1
+			}`,
+			true,
+			Zones{},
+		},
+		{
+			`file`,
+			true,
+			Zones{},
+		},
+		{
+			`file ` + zoneFileName1 + ` miek.nl.`,
+			false,
+			Zones{Names: []string{"miek.nl."}},
+		},
+		{
+			`file ` + zoneFileName2 + ` dnssex.nl.`,
+			false,
+			Zones{Names: []string{"dnssex.nl."}},
+		},
+		{
+			`file ` + zoneFileName2 + ` 10.0.0.0/8`,
+			false,
+			Zones{Names: []string{"10.in-addr.arpa."}},
+		},
+	}
+
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.inputFileRules)
+		actualZones, err := fileParse(c)
+
+		if err == nil && test.shouldErr {
+			t.Fatalf("Test %d expected errors, but got no error", i)
+		} else if err != nil && !test.shouldErr {
+			t.Fatalf("Test %d expected no errors, but got '%v'", i, err)
+		} else {
+			if len(actualZones.Names) != len(test.expectedZones.Names) {
+				t.Fatalf("Test %d expected %v, got %v", i, test.expectedZones.Names, actualZones.Names)
+			}
+			for j, name := range test.expectedZones.Names {
+				if actualZones.Names[j] != name {
+					t.Fatalf("Test %d expected %v for %d th zone, got %v", i, name, j, actualZones.Names[j])
+				}
+			}
+		}
+	}
+}