pytest: allow to set stdin for lightningd

And also allow to not wait for it to be started

tests/utils.py

@@ -129,11 +129,14 @@ def __init__(self, outputDir=None, verbose=True):
         # pass it to the log matcher and not print it to stdout).
         self.log_filter = lambda line: False
 
-    def start(self):
+    def start(self, stdin=None, stdout=None):
         """Start the underlying process and start monitoring it.
         """
         logging.debug("Starting '%s'", " ".join(self.cmd_line))
-        self.proc = subprocess.Popen(self.cmd_line, stdout=subprocess.PIPE, env=self.env)
+        self.proc = subprocess.Popen(self.cmd_line,
+                                     stdin=stdin if stdin else subprocess.PIPE,
+                                     stdout=stdout if stdout else subprocess.PIPE,
+                                     env=self.env)
         self.thread = threading.Thread(target=self.tail)
         self.thread.daemon = True
         self.thread.start()
@@ -496,10 +499,11 @@ def cmd_line(self):
 
         return self.cmd_prefix + [self.executable] + opts
 
-    def start(self):
+    def start(self, stdin=None, stdout=None, wait_for_initialized=True):
         self.opts['bitcoin-rpcport'] = self.rpcproxy.rpcport
-        TailableProc.start(self)
-        self.wait_for_log("Server started with public key")
+        TailableProc.start(self, stdin, stdout)
+        if wait_for_initialized:
+            self.wait_for_log("Server started with public key")
         logging.info("LightningD started")
 
     def wait(self, timeout=10):