[LyX/master] lyx2lyx tests: Check for possible endless expansion

[Kornel Benko]

commit 40e32d4d270d8b46f1fa0f82d867354bc55ba075
Author: Kornel Benko <kor...@lyx.org>
Date:   Mon Jan 22 14:43:50 2018 +0100

    lyx2lyx tests: Check for possible endless expansion
    
    If, after the 10th iteration, the exported lyx16x file still
    differs from the one in the previous iteration, the test
    is marked as failing, even if still loadable.
---
 development/autotests/export.cmake |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/development/autotests/export.cmake 
b/development/autotests/export.cmake
index 5df24da..3800ef4 100755
--- a/development/autotests/export.cmake
+++ b/development/autotests/export.cmake
@@ -97,7 +97,7 @@ set(ENV{LANG} "en_US.UTF-8") # to get all error-messages in 
english
 if (extension MATCHES "\\.lyx$")
   include(${TOP_SRC_DIR}/development/autotests/CheckLoadErrors.cmake)
   get_md5sum(LYX_SOURCE source_md5sum _err)
-  foreach(_lv RANGE 1 5)
+  foreach(_lv RANGE 1 20)
     set(result_file_base "${result_file_base}.${LYX_FORMAT_NUM}")
     set(result_file_name "${result_file_base}.lyx")
     file(REMOVE "${result_file_name}" "${result_file_name}.emergency" )
@@ -135,6 +135,13 @@ if (extension MATCHES "\\.lyx$")
     if(result_md5sum STREQUAL ${source_md5sum})
       message(STATUS "Source(${LYX_SOURCE}) and dest(${result_file_name}) are 
equal")
       break()
+    else()
+      message(STATUS "Source(${LYX_SOURCE}) and dest(${result_file_name}) are 
still different")
+      if (_lv GREATER 10)
+       set(_err 1)
+       message(STATUS "Possible endless loop encountered")
+       break()
+      endif()
     endif()
     set(source_md5sum ${result_md5sum})
     set(LYX_SOURCE ${result_file_name})