middleware/file: fix delegations (#376)

Fix the delegation handling in the *file* and *dnssec* middleware.
Refactor tests a bit and show that they are failling.

Add a Tree printer, cleanups and tests.
Fix wildcard test - should get no answer from empty-non-terminal

middleware/file/zone_test.go

@@ -1,4 +1,30 @@
 package file
 
-// TODO tests here.
-// see secondary_test.go for some infrastructure stuff.
+import "testing"
+
+func TestNameFromRight(t *testing.T) {
+	z := NewZone("example.org.", "stdin")
+
+	tests := []struct {
+		in       string
+		labels   int
+		shot     bool
+		expected string
+	}{
+		{"example.org.", 0, false, "example.org."},
+		{"a.example.org.", 0, false, "example.org."},
+		{"a.example.org.", 1, false, "a.example.org."},
+		{"a.example.org.", 2, true, "a.example.org."},
+		{"a.b.example.org.", 2, false, "a.b.example.org."},
+	}
+
+	for i, tc := range tests {
+		got, shot := z.nameFromRight(tc.in, tc.labels)
+		if got != tc.expected {
+			t.Errorf("Test %d: expected %s, got %s\n", i, tc.expected, got)
+		}
+		if shot != tc.shot {
+			t.Errorf("Test %d: expected shot to be %t, got %t\n", i, tc.shot, shot)
+		}
+	}
+}