add black-box debug harness

internal/harness/input_test.go

@@ -0,0 +1,22 @@
+package harness
+
+import "testing"
+
+func TestEncodeChord(t *testing.T) {
+	tests := map[string]string{
+		"ctrl-k":       "\x0b",
+		"ctrl-k-kitty": "\x1b[107;5u",
+		"ctrl-k-xterm": "\x1b[27;5;107~",
+		"enter":        "\r",
+		"down":         "\x1b[B",
+	}
+	for name, want := range tests {
+		got, err := EncodeChord(name)
+		if err != nil {
+			t.Fatalf("%s: %v", name, err)
+		}
+		if string(got) != want {
+			t.Fatalf("%s = %q, want %q", name, string(got), want)
+		}
+	}
+}