Added stricter test case that show the problem and implement fixes for them

plugin/UltiSnips/__init__.py

@@ -694,8 +694,8 @@ class SnippetManager(object):
                     this_entered = vim.current.line[:self._vstate.pos.col]
                     self._chars_entered('\n' + cline + this_entered, 1)
                 if line_was_shortened and user_didnt_enter_newline:
-                    self._backspace(len(self._vstate.last_line)-len(lline))
-                    self._chars_entered('\n' + cline, 1)
+                    self._backspace(self._vstate.ppos.col-len(lline))
+                    self._chars_entered('\n' + cline[:len(cline)-(len(self._vstate.last_line)-self._vstate.ppos.col)], 1)
                 else:
                     pentered = lline[self._vstate.ppos.col:]
                     this_entered = vim.current.line[:self._vstate.pos.col]

test.py

@@ -226,6 +226,43 @@ class MultilineExpandWithFormatoptionsOn_ExceptCorrectResult(_VimTest):
     def _options_off(self):
         self.send(":set tw=0\n")
 
+class MultilineExpandWithFormatoptionsOnTextAfter_ExceptCorrectResult(_VimTest):
+    """Testcase for lp:719998"""
+    snippets = ("test", "${1:longer expand}after\nstart$1end")
+    keys = ("test" + EX + "This is a longer snippet that should wrap properly "
+            "and the mirror below should work as well")
+    wanted = \
+"""This is a longer
+snippet that should
+wrap properly and
+the mirror below
+should work as wellafter
+startThis is a longer
+snippet that should
+wrap properly and
+the mirror below
+should work as wellend"""
+    def _options_on(self):
+        self.send(":set tw=20\n")
+    def _options_off(self):
+        self.send(":set tw=0\n")
+
+class MultilineExpandWithFormatoptionsWrapOnLongWord_ExceptCorrectResult(_VimTest):
+    """Testcase for lp:719998"""
+    snippets = ("test", "${1:longer expand}after\nstart$1end")
+    keys = ("test" + EX + "This is a longersnippet that should wrap properly")
+    wanted = \
+"""This is a
+longersnippet that
+should wrap properlyafter
+startThis is a
+longersnippet that
+should wrap properlyend"""
+
+    def _options_on(self):
+        self.send(":set tw=20\n")
+    def _options_off(self):
+        self.send(":set tw=0\n")
 
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