Support printing test vectors of Option type (needed for diversifiers).

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

tv_output.py

@@ -10,6 +10,12 @@ def chunk(h):
     hstr = str(h, 'utf-8')
     return '0x' + ', 0x'.join([hstr[i:i+2] for i in range(0, len(hstr), 2)])
 
+class Some(object):
+    def __init__(self, thing):
+       self.thing = thing
+
+def option(x):
+    return Some(x) if x else None
 
 #
 # JSON (with string comments)
@@ -17,6 +23,9 @@ def chunk(h):
 #
 
 def tv_value_json(value, bitcoin_flavoured):
+    if isinstance(value, Some):
+        value = value.thing
+
     if type(value) == bytes:
         if bitcoin_flavoured and len(value) == 32:
             value = value[::-1]
@@ -54,6 +63,20 @@ def tv_bytes_rust(name, value, pad):
         pad,
     ))
 
+def tv_option_bytes_rust(name, value, pad):
+    if value:
+        print('''%s%s: Some([
+    %s%s
+%s]),''' % (
+            pad,
+            name,
+            pad,
+            chunk(hexlify(value.thing)),
+            pad,
+        ))
+    else:
+        print('%s%s: None,' % (pad, name))
+
 def tv_int_rust(name, value, pad):
     print('%s%s: %d,' % (pad, name, value))
 
@@ -61,6 +84,8 @@ def tv_part_rust(name, value, indent=3):
     pad = '    ' * indent
     if type(value) == bytes:
         tv_bytes_rust(name, value, pad)
+    elif isinstance(value, Some) or value is None:
+        tv_option_bytes_rust(name, value, pad)
     elif type(value) == int:
         tv_int_rust(name, value, pad)
     else: