ONNX will build googletest from a Git checkout.  Patch CMake to use our
googletest package and enable tests by default.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0aa9fda2..a573170c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,7 +22,7 @@ option(BUILD_ONNX_PYTHON "Build Python binaries" OFF)
 option(ONNX_GEN_PB_TYPE_STUBS "Generate protobuf python type stubs" ON)
 option(ONNX_WERROR "Build with Werror" OFF)
 option(ONNX_COVERAGE "Build with coverage instrumentation" OFF)
-option(ONNX_BUILD_TESTS "Build ONNX C++ APIs Tests" OFF)
+option(ONNX_BUILD_TESTS "Build ONNX C++ APIs Tests" ON)
 option(ONNX_USE_LITE_PROTO "Use lite protobuf instead of full." OFF)
 option(ONNXIFI_ENABLE_EXT "Enable onnxifi extensions." OFF)
 if(NOT DEFINED ONNX_ML)
@@ -82,8 +82,10 @@ if(CMAKE_SYSTEM_NAME STREQUAL "AIX")
 endif()

 if(ONNX_BUILD_TESTS)
-  list(APPEND CMAKE_MODULE_PATH ${ONNX_ROOT}/cmake/external)
-  include(googletest)
+  find_package(GTest REQUIRED)
+  if(NOT GTest_FOUND)
+    message(FATAL_ERROR "cannot find googletest")
+  endif()
 endif()

 if((ONNX_USE_LITE_PROTO AND TARGET protobuf::libprotobuf-lite) OR ((NOT ONNX_USE_LITE_PROTO) AND TARGET protobuf::libprotobuf))
diff --git a/cmake/unittest.cmake b/cmake/unittest.cmake
index e29a93ff..ae146390 100644
--- a/cmake/unittest.cmake
+++ b/cmake/unittest.cmake
@@ -7,7 +7,7 @@
 
 find_package(Threads)
 
-set(${UT_NAME}_libs ${googletest_STATIC_LIBRARIES})
+set(${UT_NAME}_libs ${GTEST_LIBRARIES})
 
 list(APPEND ${UT_NAME}_libs onnx)
 list(APPEND ${UT_NAME}_libs onnx_proto)
@@ -22,9 +22,9 @@
   list(REMOVE_DUPLICATES _UT_SOURCES)
 
   add_executable(${_UT_TARGET} ${_UT_SOURCES})
-  add_dependencies(${_UT_TARGET} onnx onnx_proto googletest)
+  add_dependencies(${_UT_TARGET} onnx onnx_proto)
 
   target_include_directories(${_UT_TARGET}
-                             PUBLIC ${googletest_INCLUDE_DIRS}
+                             PUBLIC ${GTEST_INCLUDE_DIRS}
                                     ${ONNX_INCLUDE_DIRS}
                                     ${PROTOBUF_INCLUDE_DIRS}
                                     ${ONNX_ROOT}g/gnu?id=461602d07c8da0e29bae392270f4ef3fd4f7fffb'>gnu</a>/<a href='/guix/log/gnu/packages?id=461602d07c8da0e29bae392270f4ef3fd4f7fffb'>packages</a>/<a href='/guix/log/gnu/packages/tryton.scm?id=461602d07c8da0e29bae392270f4ef3fd4f7fffb'>tryton.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/tryton.scm?id=461602d07c8da0e29bae392270f4ef3fd4f7fffb&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-07 17:53:37 +0200'>2023-04-07</span></td><td><a href='/guix/commit/gnu/packages/tryton.scm?id=acdb42e5d09a504d521d8b632c2c4a66d70f94e4'>gnu: Purge pre-1.3.0 deprecated packages.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/bioinformatics.scm (deeptools): Remove variable.
* gnu/packages/efi.scm (efi_analyzer): Ditto.
* gnu/packages/guile.scm (guile-2.2/bug-fix, guile-json): Ditto.
* gnu/packages/image.scm (libjpeg): Ditto.
* gnu/packages/kde.scm (kdevplatform): Ditto
* gnu/packages/linphone.scm (linphoneqt): Ditto.
* gnu/packages/maths.scm (blis-sandybridge, blis-haswell, blis-knl): Ditto.
* gnu/packages/mpi.scm (hwloc-2.0): Ditto.
* gnu/packages/music.scm (python-abjad, zlfo): Ditto.
* gnu/packages/perl.scm (perl-base, perl-parent): Ditto.
* gnu/packages/tryton.scm (python-trytond): Ditto.
* gnu/packages/video.scm (gnome-mpv): Ditto.
* tests/graph.scm: Use guile-json-1.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Bruno Victal</td></tr>