diff --git a/CMakeLists.txt b/CMakeLists.txt
index e35fe4c..706db44 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,28 +11,11 @@ project(Trexio
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_STANDARD_REQUIRED ON)
 
-# ============= CONFIGURE HDF5 ============== 
-
-option(ENABLE_HDF5 "Enable HDF5 support" ON)
-
-if(ENABLE_HDF5)
-	find_package(HDF5 REQUIRED COMPONENTS C HL)
-  if(HDF5_FOUND)
-    message(STATUS "HDF5 version     :: ${HDF5_VERSION}")
-    message(STATUS "HDF5 include dir :: ${HDF5_INCLUDE_DIRS}")
-    message(STATUS "HDF5 libraries   :: ${HDF5_C_LIBRARIES}")
-  else()
-    # Download and install HDF5 library using FetchContent
-    # ...
-  endif()
-endif()
-
 # ========= DEFINE TREXIO C LIBRARY ========= 
 
 #IF DO_SHARED
 add_library(trexio SHARED
 	src/trexio.c
-	src/trexio_hdf5.c
 	src/trexio_text.c
 	)
 #ELIF DO_STATIC
@@ -45,24 +28,72 @@ set_target_properties(trexio PROPERTIES
 	)
 
 target_include_directories(trexio PRIVATE src)
-
 include_directories(include)
 
+# ============= CONFIGURE HDF5 ============== 
+
+option(ENABLE_HDF5 "Enable HDF5 support" ON)
+
 if(ENABLE_HDF5)
-	target_include_directories(trexio PRIVATE ${HDF5_C_INCLUDE_DIRS})
-	target_link_libraries(trexio PRIVATE ${HDF5_C_HL_LIBRARIES} ${HDF5_C_LIBRARIES})
+  find_package(HDF5 REQUIRED COMPONENTS C HL)
+
+  if(HDF5_FOUND)
+    message(STATUS "HDF5 version     :: ${HDF5_VERSION}")
+    message(STATUS "HDF5 include dir :: ${HDF5_INCLUDE_DIRS}")
+    message(STATUS "HDF5 libraries   :: ${HDF5_C_LIBRARIES}")
+  else()
+    # Download and install HDF5 library using FetchContent
+    # ...
+    # For now - raise a FatalError
+    message(FATAL_ERROR "HDF5 is enabled not found.")
+  endif()
+
+  target_sources(trexio PRIVATE src/trexio_hdf5.c)
+  target_compile_definitions(trexio PUBLIC HAVE_HDF5=1)
+  target_include_directories(trexio PRIVATE ${HDF5_C_INCLUDE_DIRS})
+  target_link_libraries(trexio PRIVATE 
+	  ${HDF5_C_HL_LIBRARIES} 
+	  ${HDF5_C_LIBRARIES})
 endif()
 
 # ================= TESTING ================= 
 
 enable_testing()
 
-add_executable(io_all tests/io_all.c)
-target_link_libraries(io_all PRIVATE trexio)
-add_test(
-  NAME io_all
-  COMMAND $<TARGET_FILE:io_all>
-)
+# create the lists of tests
+set(Tests_text
+  open_text
+  io_dset_float_text
+  io_dset_str_text
+  io_safe_dset_float_text
+  io_dset_int_text
+  io_num_text
+  io_str_text
+  overwrite_all_text
+  )
+
+if(ENABLE_HDF5)
+  set(Tests_hdf5
+    open_hdf5
+    io_dset_float_hdf5
+    io_dset_str_hdf5
+    io_safe_dset_float_hdf5
+    io_dset_int_hdf5
+    io_num_hdf5
+    io_str_hdf5
+    overwrite_all_hdf5
+    )
+  set(Tests io_all ${Tests_text} ${Tests_hdf5})
+else()
+  set(Tests ${Tests_text})
+endif()
+
+# Add all the ADD_TEST for each test
+foreach(test ${Tests})
+  add_executable(${test} tests/${test}.c)
+  target_link_libraries(${test} PRIVATE trexio)
+  add_test(NAME ${test} COMMAND $<TARGET_FILE:${test}>)
+endforeach ()
 
 # ============= INSTALL TREXIO ==============