Add back the testing-suite

Signed-off-by: Cristian Le <git@lecris.dev>

Author: LecrisUT

TESTING/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.26...4.0)
+
+## Old test-suite to be modernized
+# include only if this is included via `add_subdirectory`
+
+if(DEFINED SCALAPACK_SOURCE_DIR)
+    add_subdirectory(traditional)
+endif()
+
+## Modern test-suite is an independent project
+
+# TODO: Add the implementations
+project(scalapack-tests
+    LANGUAGES C Fortran
+)
+enable_testing()