Regtesting: Introduce tests/UNIT_TESTS file

tests/UNIT_TESTS

@@ -0,0 +1,12 @@
+# Binaries listed in this file will be executed as part of cp2k's regression testing.
+# The binary name can be followed by required flags as reported by `cp2k --version`.
+
+dbt_tas_unittest
+dbt_unittest
+grid_unittest
+libcp2k_unittest
+memory_utilities_unittest
+nequip_unittest                                          libtorch
+parallel_rng_types_unittest
+
+#EOF

tools/regtesting/do_regtest.py

@@ -98,12 +98,17 @@ async def main() -> None:
     shutil.copytree(cfg.cp2k_root / "tests", cfg.work_base_dir)
     print(" done")
 
-    # Discover unit tests.
-    unittest_batch = Batch("UNIT", cfg)
-    unittest_batch.workdir.mkdir()
-    unittest_glob = (cfg.cp2k_root / "exe" / cfg.arch).glob(f"*_unittest.{cfg.version}")
-    for exe in unittest_glob:
-        unittest_batch.unittests.append(Unittest(exe.stem, unittest_batch.workdir))
+    batches: List[Batch] = []
+
+    # Read UNIT_TESTS.
+    unit_tests_fn = cfg.cp2k_root / "tests" / "UNIT_TESTS"
+    for line in unit_tests_fn.read_text(encoding="utf8").split("\n"):
+        line = line.split("#", 1)[0].strip()
+        if line:
+            batch = Batch(f"UNIT/{line}", cfg)
+            batch.workdir.mkdir(parents=True)
+            batch.unittests.append(Unittest(line.split()[0], batch.workdir))
+            batches.append(batch)
 
     # Read TEST_TYPES.
     test_types_fn = cfg.cp2k_root / "tests" / "TEST_TYPES"
@@ -112,7 +117,6 @@ async def main() -> None:
     test_types += [TestType(l) for l in lines[1 : int(lines[0]) + 1]]
 
     # Read TEST_DIRS.
-    batches: List[Batch] = [unittest_batch]
     test_dirs_fn = cfg.cp2k_root / "tests" / "TEST_DIRS"
     for line in test_dirs_fn.read_text(encoding="utf8").split("\n"):
         line = line.split("#", 1)[0].strip()