ci: enable rest and ud libs when building samples in cmake (#15829)

Author: scotthart

cmake/GoogleCloudCppFeatures.cmake

@@ -403,6 +403,13 @@ macro (google_cloud_cpp_enable_cleanup)
         set(GOOGLE_CLOUD_CPP_ENABLE_REST ON)
     endif ()
 
+    # We need the REST libraries for the full suite of samples.
+    if (NOT GOOGLE_CLOUD_CPP_ENABLE_REST
+        AND BUILD_TESTING
+        AND GOOGLE_CLOUD_CPP_ENABLE_CXX_EXCEPTIONS)
+        set(GOOGLE_CLOUD_CPP_ENABLE_REST ON)
+    endif ()
+
     list(REMOVE_DUPLICATES GOOGLE_CLOUD_CPP_ENABLE)
 endmacro ()
 

google/cloud/CMakeLists.txt

@@ -68,7 +68,11 @@ if (GOOGLE_CLOUD_CPP_ENABLE_REST AND GOOGLE_CLOUD_CPP_ENABLE_GRPC)
     )
 endif ()
 
-if (universe_domain IN_LIST GOOGLE_CLOUD_CPP_ENABLE)
+# We need the universe_domain library for the full suite of samples if it isn't
+# already enabled.
+if (universe_domain IN_LIST GOOGLE_CLOUD_CPP_ENABLE
+    OR BUILD_TESTING
+    AND GOOGLE_CLOUD_CPP_ENABLE_CXX_EXCEPTIONS)
     include(
         "${CMAKE_CURRENT_SOURCE_DIR}/google_cloud_cpp_universe_domain.cmake")
     add_subdirectory(universe_domain)