Auto merge of #2662 - bstaletic:filepath_escaping3, r=micbou

Filepath space escaping

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- [x] I have read and understood YCM's [CONTRIBUTING][cont] document.
- [x] I have read and understood YCM's [CODE_OF_CONDUCT][code] document.
- [x] I have included tests for the changes in my PR. If not, I have included a
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[Please explain **in detail** why the changes in this PR are needed.]

This provides the most basic test for `EscapedFilepath()`.

[cont]: https://github.com/Valloric/YouCompleteMe/blob/master/CONTRIBUTING.md
[code]: https://github.com/Valloric/YouCompleteMe/blob/master/CODE_OF_CONDUCT.md

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python/ycm/tests/vimsupport_test.py

@@ -1595,3 +1595,10 @@ def InsertNamespace_append_test( vim_current, *args ):
                       '    int taco;',
                       '    List salad = new List' ]
   AssertBuffersAreEqualAsBytes( expected_buffer, vim_current.buffer )
+
+
+def EscapedFilepath_test():
+  eq_( vimsupport.EscapedFilepath( '/path/ with /sp ac es' ),
+       '/path/\ with\ /sp\ ac\ es' )
+  eq_( vimsupport.EscapedFilepath( ' relative path/ with / spaces ' ),
+       '\ relative\ path/\ with\ /\ spaces\ ' )