Hi, Sergey,

thanks for the patch! See comments below.

It is useful to update the environment variable for some tests. For
CMake versions >= 3.22, we can use ENVIRONMENT_MODIFICATION [1] instead.
But unless we bump the CMake version, this macro is a workaround.

[1]: https://cmake.org/cmake/help/latest/prop_test/ENVIRONMENT_MODIFICATION.html

Part of tarantool/tarantool#9898
---
 test/tarantool-tests/CMakeLists.txt | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/test/tarantool-tests/CMakeLists.txt b/test/tarantool-tests/CMakeLists.txt
index 11a84496..4530c9fd 100644
--- a/test/tarantool-tests/CMakeLists.txt
+++ b/test/tarantool-tests/CMakeLists.txt
@@ -18,6 +18,29 @@ macro(BuildTestCLib lib sources)
   set(LD_LIBRARY_PATH "${CMAKE_CURRENT_BINARY_DIR}:${LD_LIBRARY_PATH}" PARENT_SCOPE)
 endmacro()
 
+# FIXME: This is used only due to ancient CMake requirements.
+# If we update to CMake >= 3.22, we can use
+# ENVIRONMENT_MODIFICATION [1] instead.
+# [1]: https://cmake.org/cmake/help/latest/prop_test/ENVIRONMENT_MODIFICATION.html

+macro(AppendTestEnvVar testname var value)

I would rename macro to something like "ModifyTestEnv"

because it appends env var when variable with the same name was not found

and modifies it when variable exist.

+  get_test_property(${testname} ENVIRONMENT old_env)
+  foreach(loopvar "${old_env}")
+    if(loopvar MATCHES "^${var}=(.*)")
+      set(envvar_found TRUE)
+      set(loopvar "${var}=${value}${CMAKE_MATCH_1}")
+    endif()
+    list(APPEND new_env "${loopvar}")
+  endforeach()
+  if(NOT "${envvar_found}")
+    list(APPEND new_env "${var}=${value}")
+  endif()
+  set_tests_properties(${testname} PROPERTIES ENVIRONMENT "${new_env}")
+
+  unset(envvar_found)
+  unset(old_env)
+  unset(new_env)
+endmacro()
+
 add_subdirectory(ffi-ccall)
 add_subdirectory(fix-bit-shift-generation)
 add_subdirectory(gh-4427-ffi-sandwich)