Disable test on prometheus-cpp which not need (#1363)

CMakeLists.txt

@@ -274,7 +274,10 @@ if(WITH_PROMETHEUS)
   if(NOT prometheus-cpp_FOUND)
     message("Trying to use local prometheus-cpp from submodule")
     if(EXISTS ${PROJECT_SOURCE_DIR}/third_party/prometheus-cpp/.git)
+      set(SAVED_ENABLE_TESTING ${ENABLE_TESTING})
+      set(ENABLE_TESTING OFF)
       add_subdirectory(third_party/prometheus-cpp)
+      set(ENABLE_TESTING ${SAVED_ENABLE_TESTING})
     else()
       message(
         FATAL_ERROR
@@ -361,7 +364,7 @@ if(BUILD_TESTING)
         ${CMAKE_BINARY_DIR}/lib/libgmock.a)
   elseif(WIN32)
     # Make sure we are always bootsrapped with vcpkg on Windows
-    find_package(GTest)
+    find_package(GTest REQUIRED)
     if(NOT (GTEST_FOUND OR GTest_FOUND))
       install_windows_deps()
       find_package(GTest REQUIRED)

exporters/prometheus/test/CMakeLists.txt

@@ -1,11 +1,13 @@
-foreach(testname prometheus_exporter_test prometheus_collector_test
-                 prometheus_exporter_utils_test)
-  add_executable(${testname} "${testname}.cc")
-  target_link_libraries(
-    ${testname} ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
-    prometheus_exporter_deprecated prometheus-cpp::pull)
-  gtest_add_tests(
-    TARGET ${testname}
-    TEST_PREFIX exporter.
-    TEST_LIST ${testname})
-endforeach()
+if(WITH_METRICS_PREVIEW)
+  foreach(testname prometheus_exporter_test prometheus_collector_test
+                   prometheus_exporter_utils_test)
+    add_executable(${testname} "${testname}.cc")
+    target_link_libraries(
+      ${testname} ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
+      prometheus_exporter_deprecated prometheus-cpp::pull)
+    gtest_add_tests(
+      TARGET ${testname}
+      TEST_PREFIX exporter.
+      TEST_LIST ${testname})
+  endforeach()
+endif()