Move complete test to pexpect

tests/pexpects/complete.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+from pexpect_helper import SpawnedProc
+
+sp = SpawnedProc()
+send, sendline, sleep, expect_prompt, expect_re = sp.send, sp.sendline, sp.sleep, sp.expect_prompt, sp.expect_re
+expect_prompt()
+
+sendline("""
+    complete -c my_is -n 'test (count (commandline -opc)) = 1' -xa arg
+    complete -c my_is -n '__fish_seen_subcommand_from not' -xa '(
+	set -l cmd (commandline -opc) (commandline -ct)
+	set cmd (string join " " my_is $cmd[3..-1])" "
+	commandline --replace --current-process $cmd
+	complete -C"$cmd"
+    )'
+""")
+
+send("my_is not \t")
+send("still.alive")
+expect_re(".*still.alive")