Minimize cuopt_static linkage in tests to avoid package size explosion

PR #1526 switched all tests to link cuopt_static, which inflates
libcuopt-tests from ~75 MB to ~5 GB (confirmed from CI artifacts)
because each of ~36 test executables embeds the full cuopt object graph.

This commit introduces ConfigureInternalTest for tests that genuinely
need access to hidden symbols, and keeps ConfigureTest on the shared
library for tests that only use the public API.

Only routing tests are switched to ConfigureInternalTest: they all
include routing_test.cuh which pulls in cuopt::routing::detail types
(solution_t, problem_t, fleet_order_constraints_t, md_utils, etc.).

MIP, LP, QP, SOCP, dual_simplex, distance engine, CLI, and utility
tests use only public cuopt API or raft::detail inline headers (which
are compiled into the TU, not linked from cuopt.so), so they stay on
the shared library.

GRPC tests are left unchanged as they have explicit target_link_libraries
and grpc_client.cpp symbols lack CUOPT_EXPORT.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ramakrishnap-nv

cpp/tests/CMakeLists.txt

@@ -55,7 +55,7 @@ function(ConfigureTest CMAKE_TEST_NAME)
 
     target_link_libraries(${CMAKE_TEST_NAME}
        PRIVATE
-        cuopt_static
+        cuopt
         cuopttestutils
         GTest::gmock
         GTest::gmock_main
@@ -81,6 +81,52 @@ function(ConfigureTest CMAKE_TEST_NAME)
     )
 endfunction()
 
+# ConfigureInternalTest(NAME source1.cu ... [LABELS ...])
+#
+# Like ConfigureTest but links cuopt_static instead of the shared library.
+# Use only for tests that access symbols in cuopt::*::detail namespaces or
+# include headers from cpp/src/ that are not part of the public API.
+function(ConfigureInternalTest CMAKE_TEST_NAME)
+    cmake_parse_arguments(CT "" "" "LABELS" ${ARGN})
+    add_executable(${CMAKE_TEST_NAME} ${CT_UNPARSED_ARGUMENTS})
+    target_include_directories(${CMAKE_TEST_NAME}
+        PRIVATE
+        "${CUOPT_TEST_DIR}/../src"
+        "${CUOPT_TEST_DIR}/../src/io"
+        "${CUOPT_TEST_DIR}"
+        "${papilo_SOURCE_DIR}/src"
+        "${papilo_BINARY_DIR}"
+        "${pslp_SOURCE_DIR}/include"
+        "${dejavu_SOURCE_DIR}"
+    )
+
+    target_link_libraries(${CMAKE_TEST_NAME}
+       PRIVATE
+        cuopt_static
+        cuopttestutils
+        GTest::gmock
+        GTest::gmock_main
+        GTest::gtest
+        GTest::gtest_main
+        ${CUOPT_PRIVATE_CUDA_LIBS}
+    )
+    if(NOT DEFINED INSTALL_TARGET OR "${INSTALL_TARGET}" STREQUAL "")
+      target_link_options(${CMAKE_TEST_NAME} PRIVATE -Wl,--enable-new-dtags)
+    endif()
+
+    add_test(NAME ${CMAKE_TEST_NAME} COMMAND ${CMAKE_TEST_NAME})
+
+    if(CT_LABELS)
+        set_tests_properties(${CMAKE_TEST_NAME} PROPERTIES LABELS "${CT_LABELS}")
+    endif()
+
+    install(
+        TARGETS ${CMAKE_TEST_NAME}
+        COMPONENT testing
+        DESTINATION bin/gtests/libcuopt
+        EXCLUDE_FROM_ALL
+    )
+endfunction()
 
 # ####################################################################
 # - set rapids dataset path ----------------------------------------------------------------------

cpp/tests/routing/CMakeLists.txt

@@ -3,33 +3,36 @@
 # SPDX-License-Identifier: Apache-2.0
 # cmake-format: on
 
-ConfigureTest(ROUTING_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_routing_test.cu
+# All routing tests include routing_test.cuh which pulls in cuopt::routing::detail
+# types (solution_t, problem_t, fleet_order_constraints_t, md_utils, etc.).
+# They must link against cuopt_static to access those hidden symbols.
+ConfigureInternalTest(ROUTING_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_routing_test.cu
     LABELS routing)
-ConfigureTest(ROUTING_GES_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_ges_test.cu
+ConfigureInternalTest(ROUTING_GES_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_ges_test.cu
     LABELS routing)
 
-ConfigureTest(VEHICLE_ORDER_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_vehicle_order_match.cu
+ConfigureInternalTest(VEHICLE_ORDER_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_vehicle_order_match.cu
     LABELS routing)
-ConfigureTest(VEHICLE_TYPES_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_vehicle_types_test.cu
+ConfigureInternalTest(VEHICLE_TYPES_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_vehicle_types_test.cu
     LABELS routing)
-ConfigureTest(OBJECTIVE_FUNCTION_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_objective_function_test.cu
+ConfigureInternalTest(OBJECTIVE_FUNCTION_TEST ${CMAKE_CURRENT_SOURCE_DIR}/level0/l0_objective_function_test.cu
     LABELS routing)
 
 # ##################################################################################################
 # - L1 advanced retail tests --------------------------------------------------------------------------
-ConfigureTest(RETAIL_L1TEST ${CMAKE_CURRENT_SOURCE_DIR}/level1/l1_retail_test.cu
+ConfigureInternalTest(RETAIL_L1TEST ${CMAKE_CURRENT_SOURCE_DIR}/level1/l1_retail_test.cu
     LABELS routing)
 
 # ##################################################################################################
 # - L1  tests for quick regression check --------------------------------------------------------------------------
-ConfigureTest(ROUTING_L1TEST ${CMAKE_CURRENT_SOURCE_DIR}/level1/l1_routing_test.cu
+ConfigureInternalTest(ROUTING_L1TEST ${CMAKE_CURRENT_SOURCE_DIR}/level1/l1_routing_test.cu
     LABELS routing)
 
 # Disabled: both tests are slow and known to be broken.
 set_tests_properties(RETAIL_L1TEST ROUTING_L1TEST PROPERTIES DISABLED TRUE)
 
 # # - ${CMAKE_CURRENT_SOURCE_DIR} unit tests ----------------------------------------------------------------------------
-ConfigureTest(ROUTING_UNIT_TEST
+ConfigureInternalTest(ROUTING_UNIT_TEST
       ${CMAKE_CURRENT_SOURCE_DIR}/unit_tests/vehicle_types.cu
       ${CMAKE_CURRENT_SOURCE_DIR}/unit_tests/breaks.cu
       ${CMAKE_CURRENT_SOURCE_DIR}/unit_tests/heterogenous_breaks.cu