TEST: add testing for extra outputs

test/api_unittest.py

@@ -10,7 +10,8 @@ from otbtf.examples.tensorflow_v2x.fcnn import train_from_tfrecords
 from otbtf.examples.tensorflow_v2x.fcnn.fcnn_model import INPUT_NAME, \
     OUTPUT_SOFTMAX_NAME, OUTPUT_ARGMAX_NAME, TARGET_NAME
 from otbtf.model import cropped_tensor_name
-from test_utils import resolve_paths, files_exist, run_command_and_compare
+from test_utils import resolve_paths, files_exist, run_command_and_compare, \
+    run_command_and_test_exist
 
 INFERENCE_MAE_TOL = 10.0  # Dummy value: we don't really care of the mae value but rather the image size etc