Solves waiting problem in an elegant way.

1. The keys after launching vim will wait until the vim is full loaded.
2. The keys after leaving vim will wait until the vim process is dead.
3. A bunch of cleanups.

test.py

@@ -29,10 +29,8 @@
 from textwrap import dedent
 import os
 import platform
-import random
 import re
 import shutil
-import string
 import subprocess
 import sys
 import tempfile
@@ -144,7 +142,7 @@ def wait_until_file_exists(file_path, times=None, interval=0.01):
 
 class TempFileManager(object):
     def __init__(self, name=""):
-        self._temp_dir = tempfile.mkdtemp(prefix="UltiSnips_" + name)
+        self._temp_dir = tempfile.mkdtemp(prefix="UltiSnipsTest_" + name)
 
     def name_temp(self, file_path):
         return os.path.join(self._temp_dir, file_path)
@@ -181,6 +179,36 @@ class VimInterface(TempFileManager):
         if wait_until_file_exists(buffer_path, 50):
             return read_text_file(buffer_path)[:-1]
 
+    def send(self, s):
+        raise NotImplementedError()
+
+    def launch(self, config=[]):
+        pid_file = self.name_temp("vim.pid")
+        done_file = self.name_temp("loading_done")
+        if os.path.exists(done_file):
+            os.remove(done_file)
+
+        post_config = []
+        post_config.append("%s << EOF" % ("py3" if PYTHON3 else "py"))
+        post_config.append("import vim")
+        post_config.append("with open('%s', 'w') as pid_file: pid_file.write(vim.eval('getpid()'))" % pid_file)
+        post_config.append("with open('%s', 'w') as done_file: pass" % done_file)
+        post_config.append("EOF")
+
+        config_path = self.write_temp("vim_config.vim",
+                dedent(os.linesep.join(config + post_config) + "\n"))
+
+        # Note the space to exclude it from shell history.
+        self.send(""" vim -u %s\r\n""" % config_path)
+        wait_until_file_exists(done_file)
+        self._vim_pid = int(open(pid_file, "r").read())
+
+    def leave_with_wait(self):
+        self.send(3*ESC + ":qa!\n")
+        while is_process_running(self._vim_pid):
+            time.sleep(.05)
+
+
 class VimInterfaceScreen(VimInterface):
     def __init__(self, session):
         VimInterface.__init__(self, "Screen")
@@ -208,9 +236,7 @@ class VimInterfaceScreen(VimInterface):
             time.sleep(.2)
 
     def detect_parsing(self):
-        self.send(""" vim -u NONE\r\n""")  # Space to exclude from shell history
-        time.sleep(1)
-
+        self.launch()
         # Send a string where the interpretation will depend on version of screen
         string = "$TERM"
         self.send("i" + string + ESC)
@@ -218,10 +244,7 @@ class VimInterfaceScreen(VimInterface):
         # If the output doesn't match the input, need to do additional escaping
         if output != string:
             self.need_screen_escapes = 1
-        self.send(ESC + ":q!\n")
-        # Make sure that vim is closed, preventing from losing the first
-        # vim test case
-        time.sleep(0.2)
+        self.leave_with_wait()
 
 class VimInterfaceTmux(VimInterface):
     def __init__(self, session):
@@ -331,7 +354,7 @@ class _VimTest(unittest.TestCase, TempFileManager):
 
     def __init__(self, *args, **kwargs):
         unittest.TestCase.__init__(self, *args, **kwargs)
-        TempFileManager.__init__(self, "Test")
+        TempFileManager.__init__(self, "Case")
 
     def runTest(self):
         # Only checks the output. All work is done in setUp().
@@ -349,14 +372,16 @@ class _VimTest(unittest.TestCase, TempFileManager):
 
     def _extra_options_pre_init(self, vim_config):
         """Adds extra lines to the vim_config list."""
+        pass
 
     def _extra_options_post_init(self, vim_config):
         """Adds extra lines to the vim_config list."""
+        pass
 
     def _before_test(self):
         """Send these keys before the test runs. Used for buffer local
         variables and other options."""
-        return ""
+        pass
 
     def _create_file(self, file_path, content):
         """Creates a file in the runtimepath that is created for this test.
@@ -438,25 +463,13 @@ class _VimTest(unittest.TestCase, TempFileManager):
         vim_config.append("vim.current.buffer[:] = %r\n" % prefilled_text)
         vim_config.append("vim.current.window.cursor = (max(len(vim.current.buffer)//2, 1), 0)")
 
-        # Create a file to signalize to the test runner that we are done with starting Vim.
-        vim_pid_file = self.name_temp("vim.pid")
-        done_file = self.name_temp("loading_done")
-        vim_config.append("with open('%s', 'w') as pid_file: pid_file.write(vim.eval('getpid()'))" %
-                vim_pid_file)
-        vim_config.append("with open('%s', 'w') as done_file: pass" % done_file)
-
         # End of python stuff.
         vim_config.append("EOF")
 
         for name, content in self.files.items():
             self._create_file(name, content)
 
-        # Now launch Vim.
-        vim_config_path = self._create_file("vim_config.vim", os.linesep.join(vim_config))
-        # Note the shell to exclude it from shell history.
-        self.vim.send(""" vim -u %s\r\n""" % vim_config_path)
-        wait_until_file_exists(done_file)
-        self._vim_pid = int(open(vim_pid_file, "r").read())
+        self.vim.launch(vim_config)
 
         self._before_test()
 
@@ -472,9 +485,7 @@ class _VimTest(unittest.TestCase, TempFileManager):
         if self.interrupt:
             print("Working directory: %s" % (self._temp_dir))
             return
-        self.vim.send(3*ESC + ":qa!\n")
-        while is_process_running(self._vim_pid):
-            time.sleep(.05)
+        self.vim.leave_with_wait()
         self.clear_temp()
 
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