add TestStamp builder

SConstruct

@@ -2,6 +2,7 @@
 
 import os
 import platform
+import subprocess
 
 import SCons.Errors
 
@@ -168,6 +169,28 @@ else:
 if "TERM" in os.environ:
     env["ENV"]["TERM"] = os.environ["TERM"]
 
+
+def test_stamp(target, source, env):
+    try:
+        subprocess.run([source[0].path]).check_returncode()
+    except subprocess.CalledProcessError as e:
+        raise SCons.Errors.BuildError(
+            errstr=f"test failed with exit code {e.returncode}"
+        )
+    with open(target[0].path, "w") as f:
+        pass
+
+
+env.Append(
+    BUILDERS={
+        "TestStamp": SCons.Builder.Builder(
+            action=test_stamp,
+            suffix=".stamp",
+            src_builder="Program",
+        )
+    }
+)
+
 if "host" in targets:
 
     if platform.system() != "Windows":

hydro/test/SConscript

@@ -2,21 +2,4 @@
 
 Import("env")
 
-import SCons.Errors
-
-import subprocess
-
-
-def test_and_stamp(target, source, env):
-    try:
-        subprocess.run([source[0].path]).check_returncode()
-    except subprocess.CalledProcessError as e:
-        raise SCons.Errors.BuildError(
-            errstr=f"test failed with exit code {e.returncode}"
-        )
-    with open(target[0].path, "w") as f:
-        pass
-
-
-test_hydro = env.Program("test_hydro.c")
-env.Command(target="test_hydro.stamp", source=test_hydro, action=test_and_stamp)
+env.TestStamp("test_hydro.c")

test/SConscript

@@ -4,7 +4,6 @@ Import("env")
 
 import SCons.Errors
 
-import subprocess
 from difflib import unified_diff
 
 
@@ -35,20 +34,9 @@ test_kat("test_lwc_hash_kat", "LWC_HASH_KAT_256.txt")
 test_kat("test_lwc_aead_kat", "LWC_AEAD_KAT_256_128.txt")
 
 
-def test_and_stamp(target, source, env):
-    try:
-        subprocess.run([source[0].path]).check_returncode()
-    except subprocess.CalledProcessError as e:
-        raise SCons.Errors.BuildError(
-            errstr=f"test failed with exit code {e.returncode}"
-        )
-    with open(target[0].path, "w") as f:
-        pass
-
-
 def test(name, extra_sources=[]):
     prog = env.Program(target=name, source=[name + ".c"] + extra_sources)
-    env.Command(target=name + ".stamp", source=prog, action=test_and_stamp)
+    env.TestStamp(prog)
 
 
 env_ed25519 = env.Clone()