diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8551897..793aed0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,8 +1,3 @@
-# TODO:
-#  - check which MSVC are compatible
-#  - cpack
-#  - ctest
-
 cmake_minimum_required(VERSION 3.1.0)
 
 project(direwolf)
@@ -17,6 +12,7 @@ set(direwolf_VERSION_SUFFIX "")
 option(FORCE_SSE "Compile with SSE instruction only" OFF)
 option(FORCE_SSSE3 "Compile with SSSE3 instruction only" OFF)
 option(FORCE_SSE41 "Compile with SSE4.1 instruction only" OFF)
+option(OPTIONAL_TEST "Compile optional test (might be broken)" OFF)
 
 # where cmake find custom modules
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/modules)
@@ -70,6 +66,7 @@ if(direwolf_VERSION_COMMIT)
   add_definitions("-DEXTRA_VERSION=${direwolf_VERSION_COMMIT}")
 endif()
 
+set(CUSTOM_SRC_DIR "${CMAKE_SOURCE_DIR}/src")
 set(CUSTOM_EXTERNAL_DIR "${CMAKE_SOURCE_DIR}/external")
 set(CUSTOM_MISC_DIR "${CUSTOM_EXTERNAL_DIR}/misc")
 set(CUSTOM_REGEX_DIR "${CUSTOM_EXTERNAL_DIR}/regex")
@@ -80,6 +77,9 @@ set(CUSTOM_TELEMETRY_DIR "${CUSTOM_SCRIPTS_DIR}/telemetry-toolkit")
 set(CUSTOM_CONF_DIR "${CMAKE_SOURCE_DIR}/conf")
 set(CUSTOM_DOC_DIR "${CMAKE_SOURCE_DIR}/doc")
 set(CUSTOM_MAN_DIR "${CMAKE_SOURCE_DIR}/man")
+set(CUSTOM_TEST_DIR "${CMAKE_SOURCE_DIR}/test")
+set(CUSTOM_TEST_SCRIPTS_DIR "${CUSTOM_TEST_DIR}/scripts")
+set(CUSTOM_SHELL_SHABANG "#!/bin/sh -e")
 
 # if we don't set build_type
 if(NOT DEFINED CMAKE_BUILD_TYPE OR "${CMAKE_BUILD_TYPE}" STREQUAL "")
@@ -124,6 +124,8 @@ elseif (WIN32)
   # compile with full multicore
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /MP")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP")
+
+  set(CUSTOM_SHELL_BIN "")
 endif()
 
 if (C_CLANG OR C_GCC)
@@ -191,6 +193,15 @@ add_subdirectory(${CUSTOM_MISC_DIR})
 # direwolf source code and utilities
 add_subdirectory(src)
 
+# ctest
+# Note CMake will generate tests only if the enable_testing() command
+# has been invoked. The CTest module invokes the command automatically
+# when the BUILD_TESTING option is ON.
+include(CTest)
+if(BUILD_TESTING)
+  add_subdirectory(test)
+endif()
+
 # manage scripts
 add_subdirectory(scripts)
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 067b0c6..4210892 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,5 +1,6 @@
 # global includes
 # not ideal but not so slow
+# otherwise use target_include_directories
 include_directories(
   ${GPSD_INCLUDE_DIRS}
   ${HAMLIB_INCLUDE_DIRS}
@@ -11,8 +12,7 @@ include_directories(
 
 # build gen_fff to create fsk_fast_filter.h
 # optimization for slow processors
-set(gen_fff_SOURCES
-  ${gen_fff_SOURCES}
+list(APPEND gen_fff_SOURCES
   demod_afsk.c
   dsp.c
   textcolor.c
@@ -32,9 +32,9 @@ add_custom_command(TARGET gen_fff
   WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
   )
 
+
 # direwolf
-set(direwolf_SOURCES
-  ${direwolf_SOURCES}
+list(APPEND direwolf_SOURCES
   direwolf.c
   aprs_tt.c
   audio_stats.c
@@ -97,29 +97,25 @@ set(direwolf_SOURCES
   )
 
 if(LINUX)
-  set(direwolf_SOURCES
-    ${direwolf_SOURCES}
+  list(APPEND direwolf_SOURCES
     audio.c
     )
   if(UDEV_FOUND)
-    set(direwolf_SOURCES
-      ${direwolf_SOURCES}
+    list(APPEND direwolf_SOURCES
       cm108.c
       )
   endif()
   elseif(WIN32) # windows
-      set(direwolf_SOURCES
-        ${direwolf_SOURCES}
-        audio_win.c
+    list(APPEND direwolf_SOURCES
+      audio_win.c
 
-        # icon
-        ${CMAKE_SOURCE_DIR}/cmake/cpack/direwolf.rc
-        )
+      # icon
+      ${CMAKE_SOURCE_DIR}/cmake/cpack/direwolf.rc
+      )
     else() # macOS freebsd openbsd
-  set(direwolf_SOURCES
-    ${direwolf_SOURCES}
-    audio_portaudio.c
-    )
+      list(APPEND direwolf_SOURCES
+        audio_portaudio.c
+        )
 endif()
 
 add_executable(direwolf
@@ -141,8 +137,7 @@ target_link_libraries(direwolf
   )
 
 # decode_aprs
-set(decode_aprs_SOURCES
-  ${decode_aprs_SOURCES}
+list(APPEND decode_aprs_SOURCES
   decode_aprs.c
   kiss_frame.c
   ax25_pad.c
@@ -178,8 +173,7 @@ target_link_libraries(decode_aprs
 
 # Convert between text and touch tone representation.
 # text2tt
-set(text2tt_SOURCES
-  ${text2tt_SOURCES}
+list(APPEND text2tt_SOURCES
   tt_text.c
   )
 
@@ -196,8 +190,7 @@ target_link_libraries(text2tt
   )
 
 # tt2text
-set(tt2text_SOURCES
-  ${tt2text_SOURCES}
+list(APPEND tt2text_SOURCES
   tt_text.c
   )
 
@@ -216,8 +209,7 @@ target_link_libraries(tt2text
 
 # Convert between Latitude/Longitude and UTM coordinates.
 # ll2utm
-set(ll2utm_SOURCES
-  ${ll2utm_SOURCES}
+list(APPEND ll2utm_SOURCES
   ll2utm.c
   textcolor.c
   )
@@ -232,8 +224,7 @@ target_link_libraries(ll2utm
   )
 
 # utm2ll
-set(utm2ll_SOURCES
-  ${utm2ll_SOURCES}
+list(APPEND utm2ll_SOURCES
   utm2ll.c
   textcolor.c
   )
@@ -250,8 +241,7 @@ target_link_libraries(utm2ll
 
 # Convert from log file to GPX.
 # log2gpx
-set(log2gpx_SOURCES
-  ${log2gpx_SOURCES}
+list(APPEND log2gpx_SOURCES
   log2gpx.c
   textcolor.c
   )
@@ -267,8 +257,7 @@ target_link_libraries(log2gpx
 
 # Test application to generate sound.
 # gen_packets
-set(gen_packets_SOURCES
-  ${gen_packets_SOURCES}
+list(APPEND gen_packets_SOURCES
   gen_packets.c
   ax25_pad.c
   hdlc_send.c
@@ -291,8 +280,7 @@ target_link_libraries(gen_packets
 
 # Unit test for AFSK demodulator
 # atest
-set(atest_SOURCES
-  ${atest_SOURCES}
+list(APPEND atest_SOURCES
   atest.c
   demod.c
   demod_afsk.c
@@ -333,8 +321,7 @@ target_link_libraries(atest
 
 # Multiple AGWPE network or serial port clients to test TNCs side by side.
 # aclients
-set(aclients_SOURCES
-  ${aclients_SOURCES}
+list(APPEND aclients_SOURCES
   aclients.c
   ax25_pad.c
   fcs_calc.c
@@ -354,8 +341,7 @@ target_link_libraries(aclients
 # Talk to a KISS TNC.
 # Note:  kiss_frame.c has conditional compilation on KISSUTIL.
 # kissutil
-set(kissutil_SOURCES
-  ${kissutil_SOURCES}
+list(APPEND kissutil_SOURCES
   kissutil.c
   kiss_frame.c
   ax25_pad.c
@@ -383,8 +369,7 @@ target_link_libraries(kissutil
 # List USB audio adapters than can use GPIO for PTT.
 # cm108
 if(UDEV_FOUND)
-  set(cm108_SOURCES
-    ${cm108_SOURCES}
+  list(APPEND cm108_SOURCES
     cm108.c
     textcolor.c
     )
@@ -406,8 +391,7 @@ endif()
 
 # Touch Tone to Speech sample application.
 # ttcalc
-set(ttcalc_SOURCES
-  ${ttcalc_SOURCES}
+list(APPEND ttcalc_SOURCES
   ttcalc.c
   ax25_pad.c
   fcs_calc.c
@@ -438,18 +422,3 @@ install(TARGETS kissutil DESTINATION bin)
 if(UDEV_FOUND)
   install(TARGETS cm108 DESTINATION bin)
 endif()
-
-
-
-## TESTS
-# Note CMake will generate tests only if the enable_testing() command
-# has been invoked. The CTest module invokes the command automatically
-# when the BUILD_TESTING option is ON.
-include(CTest)
-if(BUILD_TESTING)
-  #  add_test(NAME <name> COMMAND <command> [<arg>...]
-  #  [CONFIGURATIONS <config>...]
-#  [WORKING_DIRECTORY <dir>])
-
-
-endif()
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
new file mode 100644
index 0000000..63160c8
--- /dev/null
+++ b/test/CMakeLists.txt
@@ -0,0 +1,569 @@
+# this is a trick to avoid to more complication
+# because configure_file() is done a configuration time
+set(CUSTOM_TEST_BINARY_DIR "${CMAKE_BINARY_DIR}/test")
+set(GEN_PACKETS_BIN "${CMAKE_BINARY_DIR}/src/gen_packets${CMAKE_EXECUTABLE_SUFFIX}")
+set(ATEST_BIN "${CMAKE_BINARY_DIR}/src/atest${CMAKE_EXECUTABLE_SUFFIX}")
+
+if(WIN32)
+  set(CUSTOM_SCRIPT_SUFFIX ".bat")
+else()
+  set(CUSTOM_SCRIPT_SUFFIX "")
+endif()
+
+set(TEST_CHECK-MODEM1200_FILE "check-modem1200")
+set(TEST_CHECK-MODEM300_FILE "check-modem300")
+set(TEST_CHECK-MODEM9600_FILE "check-modem9600")
+set(TEST_CHECK-MODEM19200_FILE "check-modem19200")
+set(TEST_CHECK-MODEM2400-a_FILE "check-modem2400-a")
+set(TEST_CHECK-MODEM2400-b_FILE "check-modem2400-b")
+set(TEST_CHECK-MODEM2400-g_FILE "check-modem2400-g")
+set(TEST_CHECK-MODEM4800_FILE "check-modem4800")
+
+# generate the scripts that run the tests
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM1200_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM1200_FILE}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM300_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM9600_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM9600_FILE}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM19200_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM19200_FILE}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM2400-a_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM2400-a_FILE}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM2400-b_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM2400-b_FILE}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM2400-g_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM2400-g_FILE}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+configure_file(
+  "${CUSTOM_TEST_SCRIPTS_DIR}/${TEST_CHECK-MODEM4800_FILE}"
+  "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM4800_FILE}${CUSTOM_SCRIPT_SUFFIX}"
+  @ONLY
+  )
+
+
+# global includes
+# not ideal but not so slow
+# otherwise use target_include_directories
+include_directories(
+  ${CUSTOM_SRC_DIR}
+  ${GPSD_INCLUDE_DIRS}
+  ${HAMLIB_INCLUDE_DIRS}
+  ${ALSA_INCLUDE_DIRS}
+  ${UDEV_INCLUDE_DIRS}
+  ${PORTAUDIO_INCLUDE_DIRS}
+  ${CUSTOM_GEOTRANZ_DIR}
+  ${CMAKE_BINARY_DIR}/src
+  )
+
+
+# Unit test for demodulators
+list(APPEND atest9_SOURCES
+  ${CUSTOM_SRC_DIR}/atest.c
+  ${CUSTOM_SRC_DIR}/demod.c
+  ${CUSTOM_SRC_DIR}/dsp.c
+  ${CUSTOM_SRC_DIR}/demod_afsk.c
+  ${CUSTOM_SRC_DIR}/demod_psk.c
+  ${CUSTOM_SRC_DIR}/demod_9600.c
+  ${CUSTOM_SRC_DIR}/hdlc_rec.c
+  ${CUSTOM_SRC_DIR}/hdlc_rec2.c
+  ${CUSTOM_SRC_DIR}/multi_modem.c
+  ${CUSTOM_SRC_DIR}/rrbb.c
+  ${CUSTOM_SRC_DIR}/fcs_calc.c
+  ${CUSTOM_SRC_DIR}/ax25_pad.c
+  ${CUSTOM_SRC_DIR}/decode_aprs.c
+  ${CUSTOM_SRC_DIR}/dwgpsnmea.c
+  ${CUSTOM_SRC_DIR}/dwgps.c
+  ${CUSTOM_SRC_DIR}/dwgpsd.c
+  ${CUSTOM_SRC_DIR}/serial_port.c
+  ${CUSTOM_SRC_DIR}/latlong.c
+  ${CUSTOM_SRC_DIR}/symbols.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  ${CUSTOM_SRC_DIR}/telemetry.c
+  ${CUSTOM_SRC_DIR}/dtime_now.c
+  ${CUSTOM_SRC_DIR}/tt_text.c
+  )
+
+add_executable(atest9
+  ${atest9_SOURCES}
+  )
+
+add_dependencies(atest9 gen_fff)
+
+target_link_libraries(atest9
+  ${MISC_LIBRARIES}
+  ${GPSD_LIBRARIES}
+  Threads::Threads
+  )
+
+
+# Unit test for inner digipeater algorithm
+list(APPEND dtest_SOURCES
+  ${CUSTOM_SRC_DIR}/digipeater.c
+  ${CUSTOM_SRC_DIR}/dedupe.c
+  ${CUSTOM_SRC_DIR}/pfilter.c
+  ${CUSTOM_SRC_DIR}/ax25_pad.c
+  ${CUSTOM_SRC_DIR}/fcs_calc.c
+  ${CUSTOM_SRC_DIR}/tq.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  ${CUSTOM_SRC_DIR}/decode_aprs.c
+  ${CUSTOM_SRC_DIR}/dwgpsnmea.c
+  ${CUSTOM_SRC_DIR}/dwgps.c
+  ${CUSTOM_SRC_DIR}/dwgpsd.c
+  ${CUSTOM_SRC_DIR}/serial_port.c
+  ${CUSTOM_SRC_DIR}/latlong.c
+  ${CUSTOM_SRC_DIR}/telemetry.c
+  ${CUSTOM_SRC_DIR}/symbols.c
+  ${CUSTOM_SRC_DIR}/tt_text.c
+  )
+
+add_executable(dtest
+  ${dtest_SOURCES}
+  )
+
+set_target_properties(dtest
+  PROPERTIES COMPILE_FLAGS "-DDIGITEST"
+  )
+
+target_link_libraries(dtest
+  ${MISC_LIBRARIES}
+  ${REGEX_LIBRARIES}
+  ${GPSD_LIBRARIES}
+  Threads::Threads
+  )
+
+
+# Unit test for APRStt tone seqence parsing.
+list(APPEND ttest_SOURCES
+  ${CUSTOM_SRC_DIR}/aprs_tt.c
+  ${CUSTOM_SRC_DIR}/tt_text.c
+  ${CUSTOM_SRC_DIR}/latlong.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(ttest
+  ${ttest_SOURCES}
+  )
+
+set_target_properties(ttest
+  PROPERTIES COMPILE_FLAGS "-DTT_MAIN"
+  )
+
+target_link_libraries(ttest
+  ${MISC_LIBRARIES}
+  ${GEOTRANZ_LIBRARIES}
+  )
+
+
+# Unit test for APRStt tone sequence / text conversions.
+list(APPEND tttexttest_SOURCES
+  ${CUSTOM_SRC_DIR}/tt_text.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(tttexttest
+  ${tttexttest_SOURCES}
+  )
+
+set_target_properties(tttexttest
+  PROPERTIES COMPILE_FLAGS "-DTTT_TEST"
+  )
+
+target_link_libraries(tttexttest
+  ${MISC_LIBRARIES}
+  )
+
+
+# Unit test for Packet Filtering.
+list(APPEND pftest_SOURCES
+  ${CUSTOM_SRC_DIR}/pfilter.c
+  ${CUSTOM_SRC_DIR}/ax25_pad.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  ${CUSTOM_SRC_DIR}/fcs_calc.c
+  ${CUSTOM_SRC_DIR}/decode_aprs.c
+  ${CUSTOM_SRC_DIR}/dwgpsnmea.c
+  ${CUSTOM_SRC_DIR}/dwgps.c
+  ${CUSTOM_SRC_DIR}/dwgpsd.c
+  ${CUSTOM_SRC_DIR}/serial_port.c
+  ${CUSTOM_SRC_DIR}/latlong.c
+  ${CUSTOM_SRC_DIR}/symbols.c
+  ${CUSTOM_SRC_DIR}/telemetry.c
+  ${CUSTOM_SRC_DIR}/tt_text.c
+  )
+
+add_executable(pftest
+  ${pftest_SOURCES}
+  )
+
+set_target_properties(pftest
+  PROPERTIES COMPILE_FLAGS "-DPFTEST"
+  )
+
+target_link_libraries(pftest
+  ${MISC_LIBRARIES}
+  ${REGEX_LIBRARIES}
+  ${GPSD_LIBRARIES}
+  Threads::Threads
+  )
+
+
+# Unit test for telemetry decoding.
+list(APPEND tlmtest_SOURCES
+  ${CUSTOM_SRC_DIR}/telemetry.c
+  ${CUSTOM_SRC_DIR}/ax25_pad.c
+  ${CUSTOM_SRC_DIR}/fcs_calc.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(tlmtest
+  ${tlmtest_SOURCES}
+  )
+
+set_target_properties(tlmtest
+  PROPERTIES COMPILE_FLAGS "-DTEST"
+  )
+
+target_link_libraries(tlmtest
+  ${MISC_LIBRARIES}
+  ${REGEX_LIBRARIES}
+  )
+
+
+# Unit test for location coordinate conversion.
+list(APPEND lltest_SOURCES
+  ${CUSTOM_SRC_DIR}/latlong.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(lltest
+  ${lltest_SOURCES}
+  )
+
+set_target_properties(lltest
+  PROPERTIES COMPILE_FLAGS "-DLLTEST"
+  )
+
+target_link_libraries(lltest
+  ${MISC_LIBRARIES}
+  )
+
+
+# Unit test for encoding position & object report.
+list(APPEND enctest_SOURCES
+  ${CUSTOM_SRC_DIR}/encode_aprs.c
+  ${CUSTOM_SRC_DIR}/latlong.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(enctest
+  ${enctest_SOURCES}
+  )
+
+set_target_properties(enctest
+  PROPERTIES COMPILE_FLAGS "-DEN_MAIN"
+  )
+
+target_link_libraries(enctest
+  ${MISC_LIBRARIES}
+  )
+
+
+# Unit test for KISS encapsulation.
+list(APPEND kisstest_SOURCES
+  ${CUSTOM_SRC_DIR}/kiss_frame.c
+  )
+
+add_executable(kisstest
+  ${kisstest_SOURCES}
+  )
+
+set_target_properties(kisstest
+  PROPERTIES COMPILE_FLAGS "-DKISSTEST"
+  )
+
+
+# Unit test for constructing frames besides UI.
+list(APPEND pad2test_SOURCES
+  ${CUSTOM_SRC_DIR}/ax25_pad2.c
+  ${CUSTOM_SRC_DIR}/ax25_pad.c
+  ${CUSTOM_SRC_DIR}/fcs_calc.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(pad2test
+  ${pad2test_SOURCES}
+  )
+
+set_target_properties(pad2test
+  PROPERTIES COMPILE_FLAGS "-DPAD2TEST"
+  )
+
+target_link_libraries(pad2test
+  ${MISC_LIBRARIES}
+  ${REGEX_LIBRARIES}
+  )
+
+
+# Unit Test for XID frame encode/decode.
+list(APPEND xidtest_SOURCES
+  ${CUSTOM_SRC_DIR}/xid.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(xidtest
+  ${xidtest_SOURCES}
+  )
+
+set_target_properties(xidtest
+  PROPERTIES COMPILE_FLAGS "-DXIDTEST"
+  )
+
+target_link_libraries(xidtest
+  ${MISC_LIBRARIES}
+  )
+
+
+# Unit Test for DTMF encode/decode.
+list(APPEND dtmftest_SOURCES
+  ${CUSTOM_SRC_DIR}/dtmf.c
+  ${CUSTOM_SRC_DIR}/textcolor.c
+  )
+
+add_executable(dtmftest
+  ${dtmftest_SOURCES}
+  )
+
+set_target_properties(dtmftest
+  PROPERTIES COMPILE_FLAGS "-DDTMF_TEST"
+  )
+
+
+# doing ctest on previous programs
+add_test(dtest dtest)
+add_test(ttest ttest)
+add_test(tttexttest tttexttest)
+add_test(pftest pftest)
+add_test(tlmtest tlmtest)
+add_test(lltest lltest)
+add_test(enctest enctest)
+add_test(kisstest kisstest)
+add_test(pad2test pad2test)
+add_test(xidtest xidtest)
+add_test(dtmftest dtmftest)
+
+add_test(check-modem1200 "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM1200_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+add_test(check-modem300 "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM300_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+add_test(check-modem9600 "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM9600_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+add_test(check-modem19200 "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM19200_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+add_test(check-modem2400-a "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM2400-a_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+add_test(check-modem2400-b "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM2400-b_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+add_test(check-modem2400-g "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM2400-g_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+add_test(check-modem4800 "${CUSTOM_TEST_BINARY_DIR}/${TEST_CHECK-MODEM4800_FILE}${CUSTOM_SCRIPT_SUFFIX}")
+
+# TODO  miss the audio file
+# ./atest9 -B 9600 ../walkabout9600.wav | grep "packets decoded in" >atest.out
+
+
+#  -----------------------------  Manual tests and experiments  ---------------------------
+if(OPTIONAL_TEST)
+
+  # Unit test for IGate
+  list(APPEND itest_SOURCES
+    ${CUSTOM_SRC_DIR}/igate.c
+    ${CUSTOM_SRC_DIR}/ax25_pad.c
+    ${CUSTOM_SRC_DIR}/fcs_calc.c
+    ${CUSTOM_SRC_DIR}/mheard.c
+    ${CUSTOM_SRC_DIR}/pfilter.c
+    ${CUSTOM_SRC_DIR}/telemetry.c
+    ${CUSTOM_SRC_DIR}/decode_aprs.c
+    ${CUSTOM_SRC_DIR}/dwgpsnmea.c
+    ${CUSTOM_SRC_DIR}/dwgps.c
+    ${CUSTOM_SRC_DIR}/dwgpsd.c
+    ${CUSTOM_SRC_DIR}/serial_port.c
+    ${CUSTOM_SRC_DIR}/textcolor.c
+    ${CUSTOM_SRC_DIR}/dtime_now.c
+    ${CUSTOM_SRC_DIR}/latlong.c
+    ${CUSTOM_SRC_DIR}/tt_text.c
+    ${CUSTOM_SRC_DIR}/symbols.c
+    )
+
+  add_executable(itest
+    ${itest_SOURCES}
+    )
+
+  set_target_properties(itest
+    PROPERTIES COMPILE_FLAGS "-DITEST"
+    )
+
+  target_link_libraries(itest
+    ${MISC_LIBRARIES}
+    ${GPSD_LIBRARIES}
+    Threads::Threads
+    )
+
+
+  # For demodulator tweaking experiments.
+  list(APPEND testagc_SOURCES
+    ${CUSTOM_SRC_DIR}/atest.c
+    ${CUSTOM_SRC_DIR}/demod.c
+    ${CUSTOM_SRC_DIR}/dsp.c
+    ${CUSTOM_SRC_DIR}/demod_afsk.c
+    ${CUSTOM_SRC_DIR}/demod_psk.c
+    ${CUSTOM_SRC_DIR}/demod_9600.c
+    ${CUSTOM_SRC_DIR}/hdlc_rec.c
+    ${CUSTOM_SRC_DIR}/hdlc_rec2.c
+    ${CUSTOM_SRC_DIR}/multi_modem.c
+    ${CUSTOM_SRC_DIR}/rrbb.c
+    ${CUSTOM_SRC_DIR}/fcs_calc.c
+    ${CUSTOM_SRC_DIR}/ax25_pad.c
+    ${CUSTOM_SRC_DIR}/decode_aprs.c
+    ${CUSTOM_SRC_DIR}/dwgpsnmea.c
+    ${CUSTOM_SRC_DIR}/dwgps.c
+    ${CUSTOM_SRC_DIR}/dwgpsd.c
+    ${CUSTOM_SRC_DIR}/serial_port.c
+    ${CUSTOM_SRC_DIR}/telemetry.c
+    ${CUSTOM_SRC_DIR}/dtime_now.c
+    ${CUSTOM_SRC_DIR}/latlong.c
+    ${CUSTOM_SRC_DIR}/tt_text.c
+    ${CUSTOM_SRC_DIR}/symbols.c
+    ${CUSTOM_SRC_DIR}/textcolor.c
+    )
+
+  add_executable(testagc
+    ${testagc_SOURCES}
+    )
+
+  add_dependencies(testagc gen_fff)
+
+  target_link_libraries(testagc
+    ${MISC_LIBRARIES}
+    ${GPSD_LIBRARIES}
+    Threads::Threads
+    )
+
+
+  # Send GPS location to KISS TNC each second.
+  list(APPEND walk96_SOURCES
+    ${CUSTOM_SRC_DIR}/walk96.c
+    ${CUSTOM_SRC_DIR}/dwgps.c
+    ${CUSTOM_SRC_DIR}/dwgpsnmea.c
+    ${CUSTOM_SRC_DIR}/dwgpsd.c
+    ${CUSTOM_SRC_DIR}/kiss_frame.c
+    ${CUSTOM_SRC_DIR}/latlong.c
+    ${CUSTOM_SRC_DIR}/encode_aprs.c
+    ${CUSTOM_SRC_DIR}/serial_port.c
+    ${CUSTOM_SRC_DIR}/textcolor.c
+    ${CUSTOM_SRC_DIR}/ax25_pad.c
+    ${CUSTOM_SRC_DIR}/fcs_calc.c
+    ${CUSTOM_SRC_DIR}/xmit.c
+    ${CUSTOM_SRC_DIR}/xid.c
+    ${CUSTOM_SRC_DIR}/hdlc_send.c
+    ${CUSTOM_SRC_DIR}/gen_tone.c
+    ${CUSTOM_SRC_DIR}/ptt.c
+    ${CUSTOM_SRC_DIR}/tq.c
+    ${CUSTOM_SRC_DIR}/hdlc_rec.c
+    ${CUSTOM_SRC_DIR}/hdlc_rec2.c
+    ${CUSTOM_SRC_DIR}/rrbb.c
+    ${CUSTOM_SRC_DIR}/dsp.c
+    ${CUSTOM_SRC_DIR}/multi_modem.c
+    ${CUSTOM_SRC_DIR}/demod.c
+    ${CUSTOM_SRC_DIR}/demod_afsk.c
+    ${CUSTOM_SRC_DIR}/demod_psk.c
+    ${CUSTOM_SRC_DIR}/demod_9600.c
+    ${CUSTOM_SRC_DIR}/rdq.c
+    ${CUSTOM_SRC_DIR}/server.c
+    ${CUSTOM_SRC_DIR}/morse.c
+    ${CUSTOM_SRC_DIR}/dtmf.c
+    ${CUSTOM_SRC_DIR}/audio_stats.c
+    ${CUSTOM_SRC_DIR}/dtime_now.c
+    ${CUSTOM_SRC_DIR}/dlq.c
+    )
+
+  if(LINUX)
+    list(APPEND walk96_SOURCES
+      ${CUSTOM_SRC_DIR}/audio.c
+      )
+    if(UDEV_FOUND)
+      list(APPEND walk96_SOURCES
+        ${CUSTOM_SRC_DIR}/cm108.c
+        )
+    endif()
+  elseif(WIN32) # windows
+    list(APPEND walk96_SOURCES
+      ${CUSTOM_SRC_DIR}/audio_win.c
+      )
+  else() # macOS freebsd openbsd
+    list(APPEND walk96_SOURCES
+      ${CUSTOM_SRC_DIR}/audio_portaudio.c
+      )
+  endif()
+
+  add_executable(walk96
+    ${walk96_SOURCES}
+    )
+
+  set_target_properties(walk96
+    PROPERTIES COMPILE_FLAGS "-DWALK96"
+    )
+
+  target_link_libraries(walk96
+    ${MISC_LIBRARIES}
+    ${REGEX_LIBRARIES}
+    ${GPSD_LIBRARIES}
+    ${HAMLIB_LIBRARIES}
+    ${ALSA_LIBRARIES}
+    ${PORTAUDIO_LIBRARIES}
+    ${UDEV_LIBRARIES}
+    Threads::Threads
+    )
+
+
+  # TODO  miss the audio file
+
+  # testagc
+  # ./atest -P H+ -F 0 ../01_Track_1.wav ../02_Track_2.wav | grep "packets decoded in" >atest.out
+
+  # testagc3
+  # ./gen_packets -B 300 -n 100 -o noisy3.wav
+  # ./atest3 -B 300 -P D -D 3 noisy3.wav | grep "packets decoded in" >atest.out
+
+  # testagc96
+  # ./gen_packets -B 9600 -n 100 -o noisy96.wav
+  # ./atest96 -B 9600 ../walkabout9600c.wav noisy96.wav zzz16.wav zzz16.wav zzz16.wav zzz8.wav zzz8.wav zzz8.wav | grep "packets decoded in" >atest.out
+
+  # testagc24
+  # ./atest24 -B 2400 test2400.wav | grep "packets decoded in" >atest.out
+
+  # testagc24mfj
+  # ./atest24mfj -F 1 -B 2400 ../ref-doc/MFJ-2400-PSK/2k4_short.wav
+
+  # testagc48
+  # ./atest48 -B 4800 test4800.wav | grep "packets decoded in" >atest.out
+endif()  # OPTIONAL_TEST
diff --git a/test/scripts/check-modem1200 b/test/scripts/check-modem1200
new file mode 100755
index 0000000..2b97587
--- /dev/null
+++ b/test/scripts/check-modem1200
@@ -0,0 +1,5 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -n 100 -o test12.wav
+@ATEST_BIN@ -F0 -PE -L64 -G72 test12.wav
+@ATEST_BIN@ -F1 -PE -L70 -G75 test12.wav
diff --git a/test/scripts/check-modem19200 b/test/scripts/check-modem19200
new file mode 100755
index 0000000..8d08a8e
--- /dev/null
+++ b/test/scripts/check-modem19200
@@ -0,0 +1,7 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -r 96000 -B19200 -a 170 -o test19.wav
+@ATEST_BIN@ -B19200 -F0 -L4 test19.wav
+@GEN_PACKETS_BIN@ -r 96000 -B19200 -n 100 -o test19.wav
+@ATEST_BIN@ -B19200 -F0 -L60 -G64 test19.wav
+@ATEST_BIN@ -B19200 -F1 -L64 -G68 test19.wav
diff --git a/test/scripts/check-modem2400-a b/test/scripts/check-modem2400-a
new file mode 100755
index 0000000..1faa7d1
--- /dev/null
+++ b/test/scripts/check-modem2400-a
@@ -0,0 +1,5 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -B2400 -j -n 100 -o test24-a.wav
+@ATEST_BIN@ -B2400 -j -F0 -L76 -G80 test24-a.wav
+@ATEST_BIN@ -B2400 -j -F1 -L84 -G88 test24-a.wav
diff --git a/test/scripts/check-modem2400-b b/test/scripts/check-modem2400-b
new file mode 100755
index 0000000..01479b7
--- /dev/null
+++ b/test/scripts/check-modem2400-b
@@ -0,0 +1,5 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -B2400 -J -n 100 -o test24-b.wav
+@ATEST_BIN@ -B2400 -J -F0 -L79 -G83 test24-b.wav
+@ATEST_BIN@ -B2400 -J -F1 -L87 -G91 test24-b.wav
diff --git a/test/scripts/check-modem2400-g b/test/scripts/check-modem2400-g
new file mode 100755
index 0000000..b505370
--- /dev/null
+++ b/test/scripts/check-modem2400-g
@@ -0,0 +1,4 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -B2400 -g -n 100 -o test24-g.wav
+@ATEST_BIN@ -B2400 -g -F0 -L99 -G100 test24-g.wav
diff --git a/test/scripts/check-modem300 b/test/scripts/check-modem300
new file mode 100755
index 0000000..da37dd2
--- /dev/null
+++ b/test/scripts/check-modem300
@@ -0,0 +1,5 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -B300 -n 100 -o test3.wav
+@ATEST_BIN@ -B300 -F0 -L68 -G69 test3.wav
+@ATEST_BIN@ -B300 -F1 -L71 -G75 test3.wav
diff --git a/test/scripts/check-modem4800 b/test/scripts/check-modem4800
new file mode 100755
index 0000000..2ad033d
--- /dev/null
+++ b/test/scripts/check-modem4800
@@ -0,0 +1,5 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -B4800 -n 100 -o test48.wav
+@ATEST_BIN@ -B4800 -F0 -L70 -G74 test48.wav
+@ATEST_BIN@ -B4800 -F1 -L79 -G84 test48.wav
diff --git a/test/scripts/check-modem9600 b/test/scripts/check-modem9600
new file mode 100755
index 0000000..fa5f658
--- /dev/null
+++ b/test/scripts/check-modem9600
@@ -0,0 +1,7 @@
+@CUSTOM_SHELL_SHABANG@
+
+@GEN_PACKETS_BIN@ -B9600 -a 170 -o test96.wav
+@ATEST_BIN@ -B9600 -F0 -L4 -G4 test96.wav
+@GEN_PACKETS_BIN@ -B9600 -n 100 -o test96.wav
+@ATEST_BIN@ -B9600 -F0 -L61 -G65 test96.wav
+@ATEST_BIN@ -B9600 -F1 -L62 -G66 test96.wav