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/setup_test.go

@@ -0,0 +1,65 @@
+package federation
+
+import (
+	"testing"
+
+	"github.com/mholt/caddy"
+)
+
+func TestSetup(t *testing.T) {
+	tests := []struct {
+		input            string
+		shouldErr        bool
+		expectedLen      int
+		expectedNameZone []string // contains only entry for now
+	}{
+		// ok
+		{`federation {
+			prod prod.example.org
+		}`, false, 1, []string{"prod", "prod.example.org."}},
+
+		{`federation {
+			staging staging.example.org
+			prod prod.example.org
+		}`, false, 2, []string{"prod", "prod.example.org."}},
+		{`federation {
+			staging staging.example.org
+			prod prod.example.org
+		}`, false, 2, []string{"staging", "staging.example.org."}},
+		{`federation example.com {
+			staging staging.example.org
+			prod prod.example.org
+		}`, false, 2, []string{"staging", "staging.example.org."}},
+		// errors
+		{`federation {
+		}`, true, 0, []string{}},
+		{`federation {
+			staging
+		}`, true, 0, []string{}},
+	}
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.input)
+		fed, err := federationParse(c)
+		if test.shouldErr && err == nil {
+			t.Errorf("Test %v: Expected error but found nil", i)
+			continue
+		} else if !test.shouldErr && err != nil {
+			t.Errorf("Test %v: Expected no error but found error: %v", i, err)
+			continue
+		}
+		if test.shouldErr && err != nil {
+			continue
+		}
+
+		if x := len(fed.f); x != test.expectedLen {
+			t.Errorf("Test %v: Expected map length of %d, got: %d", i, test.expectedLen, x)
+		}
+		if x, ok := fed.f[test.expectedNameZone[0]]; !ok {
+			t.Errorf("Test %v: Expected name for %s, got nothing", i, test.expectedNameZone[0])
+		} else {
+			if x != test.expectedNameZone[1] {
+				t.Errorf("Test %v: Expected zone: %s, got %s", i, test.expectedNameZone[1], x)
+			}
+		}
+	}
+}