Fix dgc & launch tests in cpu ci (#21759)

python/paddle/fluid/tests/unittests/CMakeLists.txt

@@ -257,13 +257,22 @@ if(WITH_DISTRIBUTE)
     py_test_modules(test_recv_save_op MODULES test_recv_save_op ENVS ${dist_ENVS})
     py_test_modules(test_transpiler_ops MODULES test_transpiler_ops ENVS ${dist_ENVS})
     if(WITH_DGC)
+        # if with dgc, test all dgc tests.
+        # NOTE. dist dgc tests is already in DIST_TEST_OPS
         py_test_modules(test_dgc_op MODULES test_dgc_op)
         py_test_modules(test_dgc_momentum_op MODULES test_dgc_momentum_op)
         py_test_modules(test_dgc_optimizer MODULES test_dgc_optimizer)
+    else()
+        # if not with dgc, must close all dgc tests
+        list(REMOVE_ITEM DIST_TEST_OPS "test_dist_mnist_dgc_nccl")
+        list(REMOVE_ITEM DIST_TEST_OPS "test_dist_se_resnext_dgc")
     endif()
     if(NOT APPLE)
         bash_test_modules(test_listen_and_serv_op MODULES test_listen_and_serv.sh)
+        if(WITH_GPU)
+            # NOTE. test_launch only work in gpu collective mode
             bash_test_modules(test_launch MODULES test_launch.sh)
+        endif()
         bash_test_modules(test_launch_ps MODULES test_launch_ps.sh)
 
         set(dist_ut_port 1000)

python/paddle/fluid/tests/unittests/test_dist_mnist_dgc_nccl.py

@@ -49,6 +49,8 @@ class TestDistMnistNCCL2DGC(TestDistBase):
                 log_name=flag_name)
 
     def tearDown(self):
+        import paddle.fluid as fluid
+        if fluid.core.is_compiled_with_cuda():
             result = count_of_sparse_all_reduce_calls(
                 'test_dist_mnist_dgc_nccl_tr0_err.log')
             # only 1 layer use dgc now, run_step=5, rampup_begin_step=2, so 1 * (5 - 2) = 3
@@ -76,6 +78,8 @@ class TestDistMnistNCCL2DGCMultiCards(TestDistBase):
                 log_name=flag_name)
 
     def tearDown(self):
+        import paddle.fluid as fluid
+        if fluid.core.is_compiled_with_cuda():
             result = count_of_sparse_all_reduce_calls(
                 'test_dist_mnist_dgc_nccl_dgc_2cards_local.log')
             # same as above, but use two cards