[readme] change copy instructions to avoid confusion

exercises/exercise-dunemodule/README.md

@@ -41,31 +41,23 @@ The following command will configure your new module
 mkdir appl
 ```
 
-* Copy some test case from the dumux module, e.g. test_1pfv
-    * Copy the problem, spatialparams, cc source file, input file
+* Copy some test case from the dumux module, e.g. test_1p from test/porousmediumflow/1p/implicit/compressible
+* Copy the problem, spatialparams, cc source file, input file
 
 * Adjust the CMakeLists.txt file to include your new subdirectory
 
 * Add a new CMakeLists.txt in the folder `appl` with the content
 
 ```cmake
-# linke the input file to the build folder
-add_input_file_links()
-
 # add a new finite volume 1p test
-dune_add_test(NAME test_1pfv
-              SOURCES test_1pfv.cc
-              COMPILE_DEFINITIONS TYPETAG=OnePTestCCTpfaTypeTag
-              COMMAND ${CMAKE_SOURCE_DIR}/bin/testing/runtest.py
-              CMD_ARGS  --script fuzzy
-                        --command "${CMAKE_CURRENT_BINARY_DIR}/test_1pfv test_1pfv.input -Problem.Name 1ptestcctpfa")
-
-# install sources
-install(FILES
-1ptestproblem.hh
-1ptestspatialparams.hh
-test_1pfv.cc
-DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/test/implicit/1p)
+dune_add_test(NAME test_1p_compressible_tpfa
+              SOURCES test_1p.cc
+              COMPILE_DEFINITIONS TYPETAG=OnePCompressibleTpfa
+              CMD_ARGS test_1pfv.input)
+
+# add a symlink for the input file
+dune_symlink_to_source_files(FILES "test_1p.input")
+
 ```
 
 * Reconfigure your module by running in the topmost directory of your new module