add black-box debug harness

internal/harness/input.go

@@ -0,0 +1,35 @@
+package harness
+
+import "fmt"
+
+func EncodeChord(name string) ([]byte, error) {
+	switch name {
+	case "ctrl-k":
+		return []byte{0x0b}, nil
+	case "ctrl-k-kitty":
+		return []byte("\x1b[107;5u"), nil
+	case "ctrl-k-xterm":
+		return []byte("\x1b[27;5;107~"), nil
+	case "enter":
+		return []byte{'\r'}, nil
+	case "escape":
+		return []byte{0x1b}, nil
+	case "backspace":
+		return []byte{0x7f}, nil
+	case "up":
+		return []byte("\x1b[A"), nil
+	case "down":
+		return []byte("\x1b[B"), nil
+	case "left":
+		return []byte("\x1b[D"), nil
+	case "right":
+		return []byte("\x1b[C"), nil
+	case "ctrl-n":
+		return []byte{0x0e}, nil
+	case "ctrl-p":
+		return []byte{0x10}, nil
+	case "ctrl-u":
+		return []byte{0x15}, nil
+	}
+	return nil, fmt.Errorf("unknown chord %q", name)
+}