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
@@ -6,8 +6,8 @@ include(${ONNX_ROOT}/cmake/Utils.cmake)

 find_package(Threads)

-set(${UT_NAME}_libs ${googletest_STATIC_LIBRARIES})
-set(${ONNXIFI_TEST_DRIVER}_libs ${googletest_STATIC_LIBRARIES})
+set(${UT_NAME}_libs ${GTEST_LIBRARIES})
+set(${ONNXIFI_TEST_DRIVER}_libs ${GTEST_LIBRARIES})

 list(APPEND ${UT_NAME}_libs onnx)
 list(APPEND ${UT_NAME}_libs onnx_proto)
@@ -31,10 +31,10 @@ function(AddTest)
   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}
<div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/build-utils.scm?id=6ab7ca24f229cd0ea1afbeb787cd9734b3109809&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2016-04-03 14:19:09 +0200'>2016-04-03</span></td><td><a href='/guix/commit/tests/build-utils.scm?id=a9edb211e733b8b34e67ec3b4450567e9376986f'>build: Add a Guile custom test driver using SRFI-64.</a><span class='msg-avail'>...<span class='msg-tooltip'>Before that '.log' files for scheme tests were fragmented and not
included in test-suite.log.  This unifies the semantics of SRFI-64 API
with Automake test suite.

* build-aux/test-driver.scm: New file.
* Makefile.am (SCM_LOG_DRIVER, AM_SCM_LOG_DRIVER_FLAGS): New variables.
(SCM_LOG_COMPILER, AM_SCM_LOG_FLAGS): Delete variables.
(AM_TESTS_ENVIRONMENT): Set GUILE_AUTO_COMPILE to 0.
* test-env.in: Silence guix-daemon.
* doc/guix.texi (Running the Test Suite): Describe how to display the
detailed results.  Bug reports require only 'test-suite.log' file.
* tests/base32.scm, tests/build-utils.scm, tests/builders.scm,
tests/challenge.scm, tests/cpan.scm, tests/cpio.scm, tests/cran.scm,
tests/cve.scm, tests/derivations.scm, tests/elpa.scm,
tests/file-systems.scm, tests/gem.scm, tests/gexp.scm,
tests/gnu-maintenance.scm, tests/grafts.scm, tests/graph.scm,
tests/gremlin.scm, tests/hackage.scm, tests/hash.scm,
tests/import-utils.scm, tests/lint.scm, tests/monads.scm, tests/nar.scm,
tests/packages.scm, tests/pk-crypto.scm, tests/pki.scm,
tests/profiles.scm, tests/publish.scm, tests/pypi.scm,
tests/records.scm, tests/scripts-build.scm, tests/scripts.scm,
tests/services.scm, tests/sets.scm, tests/size.scm, tests/snix.scm,
tests/store.scm, tests/substitute.scm, tests/syscalls.scm,
tests/system.scm, tests/ui.scm, tests/union.scm, tests/upstream.scm,
tests/utils.scm: Don't exit at the end of test groups.
* tests/containers.scm: Likewise.  Use 'test-skip' instead of exiting
with error code 77.
</span></span></td><td>Mathieu Lirzin</td></tr>
<tr><td><span title='2015-09-24 21:21:02 +0200'>2015-09-24</span></td><td><a href='/guix/commit/tests/build-utils.scm?id=12cd4dd3a9052491e3912ffeecbe8854ea9b971a'>tests: Unset 'LOCPATH' before running bootstrap program.</a><span class='msg-avail'>...<span class='msg-tooltip'>Reported by Mark H Weaver &lt;mhw@netris.org&gt;.

* tests/build-utils.scm ("wrap-program, one input, multiple calls"): Add
  'unsetenv' call.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2014-09-13 21:53:21 -0500'>2014-09-13</span></td><td><a href='/guix/commit/tests/build-utils.scm?id=de61113857d3ebda1f4557c5a8f6bffe63100060'>utils: Allow wrap-program to be called multiple times.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/utils.scm (wrap-program): Multiple invocations of
  wrap-program for the same file create successive wrappers.  Adjust
  docstring.
* tests/build-utils.scm: Test new wrap-program behavior.
  (%store): New variable.
</span></span></td><td>Eric Bavier</td></tr>