diff --git a/python/src/core/CMakeLists.txt b/python/src/core/CMakeLists.txt
index 9d83a210d..25221ecb7 100644
--- a/python/src/core/CMakeLists.txt
+++ b/python/src/core/CMakeLists.txt
@@ -114,6 +114,7 @@
     separators/codac2_py_SepPolygon.cpp
     separators/codac2_py_SepProj.cpp
     separators/codac2_py_SepQInter.cpp
+    separators/codac2_py_SepTest.cpp
     separators/codac2_py_SepTransform.cpp
     separators/codac2_py_SepUnion.cpp
     separators/codac2_py_SepVisible.cpp
diff --git a/python/src/core/codac2_py_core.cpp b/python/src/core/codac2_py_core.cpp
index afe9b27f3..3b0f73931 100644
--- a/python/src/core/codac2_py_core.cpp
+++ b/python/src/core/codac2_py_core.cpp
@@ -152,6 +152,7 @@ void export_SepPolarCart(py::module& m, py::class_<SepBase,pySep>& pysep);
 void export_SepPolygon(py::module& m, py::class_<SepBase,pySep>& sep);
 void export_SepProj(py::module& m, py::class_<SepBase,pySep>& sep);
 void export_SepQInter(py::module& m, py::class_<SepBase,pySep>& sep);
+void export_SepTest(py::module& m, py::class_<SepBase,pySep>& sep);
 void export_SepTransform(py::module& m, py::class_<SepBase,pySep>& sep);
 void export_SepUnion(py::module& m, py::class_<SepBase,pySep>& sep);
 void export_SepVisible(py::module& m, py::class_<SepBase,pySep>& sep);
@@ -336,6 +337,7 @@ PYBIND11_MODULE(_core, m)
   export_SepPolygon(m,py_sep);
   export_SepProj(m,py_sep);
   export_SepQInter(m,py_sep);
+  export_SepTest(m,py_sep);
   export_SepTransform(m,py_sep);
   export_SepUnion(m,py_sep);
   export_SepVisible(m,py_sep);
diff --git a/python/src/core/separators/codac2_py_SepTest.cpp b/python/src/core/separators/codac2_py_SepTest.cpp
new file mode 100644
index 000000000..7fe6c6cb8
--- /dev/null
+++ b/python/src/core/separators/codac2_py_SepTest.cpp
@@ -0,0 +1,38 @@
+/** 
+ *  Codac binding (core)
+ * ----------------------------------------------------------------------------
+ *  \date       2026
+ *  \author     Maël Godard
+ *  \copyright  Copyright 2025 Codac Team
+ *  \license    GNU Lesser General Public License (LGPL)
+ */
+
+#include <pybind11/pybind11.h>
+#include <pybind11/operators.h>
+#include <pybind11/stl.h>
+#include <codac2_SepTest.h>
+#include "codac2_py_Sep.h"
+#include "codac2_py_SepTest_docs.h" // Generated file from Doxygen XML (doxygen2docstring.py):
+
+using namespace std;
+using namespace codac2;
+namespace py = pybind11;
+using namespace pybind11::literals;
+
+void export_SepTest(py::module& m, py::class_<SepBase,pySep>& pysep)
+{
+  py::class_<SepTest> exported(m, "SepTest", pysep, SEPTEST_MAIN);
+  exported
+
+    .def(py::init([](const SepBase& s) {
+          return std::make_unique<SepTest>(s.copy());
+        }),
+      SEPTEST_SEPTEST_CONST_S_REF,
+      "s"_a)
+
+    .def("separate", &SepTest::separate,
+      BOXPAIR_SEPTEST_SEPARATE_CONST_INTERVALVECTOR_REF_CONST,
+      "x"_a)
+
+  ;
+}
\ No newline at end of file
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index db02e9526..4ad18aaa0 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -249,6 +249,8 @@
     ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepProj.h
     ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepQInter.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepQInter.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepTest.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepTest.h
     ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepTransform.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepTransform.h
     ${CMAKE_CURRENT_SOURCE_DIR}/separators/codac2_SepUnion.cpp
diff --git a/src/core/separators/codac2_SepTest.cpp b/src/core/separators/codac2_SepTest.cpp
new file mode 100644
index 000000000..ff153b203
--- /dev/null
+++ b/src/core/separators/codac2_SepTest.cpp
@@ -0,0 +1,31 @@
+/** 
+ *  SepTest.cpp
+ * ----------------------------------------------------------------------------
+ *  \date       2026
+ *  \author     Maël Godard
+ *  \copyright  Copyright 2025 Codac Team
+ *  \license    GNU Lesser General Public License (LGPL)
+ */
+
+#include "codac2_SepTest.h"
+#include <vector>
+
+using namespace std;
+
+namespace codac2
+{
+  BoxPair SepTest::separate(const IntervalVector& x) const
+  {
+    assert_release(x.size() == this->size());
+
+    BoxPair b_pair = _sep.front()->separate(x);
+
+    if (!b_pair.inner.is_empty())
+      b_pair.inner=x;
+
+    if (!b_pair.outer.is_empty())
+      b_pair.outer=x;
+      
+    return b_pair;
+  }
+}
\ No newline at end of file
diff --git a/src/core/separators/codac2_SepTest.h b/src/core/separators/codac2_SepTest.h
new file mode 100644
index 000000000..bae989c9e
--- /dev/null
+++ b/src/core/separators/codac2_SepTest.h
@@ -0,0 +1,49 @@
+/** 
+ *  \file codac2_SepTest.h
+ * ----------------------------------------------------------------------------
+ *  \date       2026
+ *  \author     Maël Godard
+ *  \copyright  Copyright 2025 Codac Team
+ *  \license    GNU Lesser General Public License (LGPL)
+ */
+
+#pragma once
+
+#include <type_traits>
+#include "codac2_Sep.h"
+#include "codac2_Collection.h"
+#include "codac2_template_tools.h"
+
+namespace codac2
+{
+  /**
+   * \brief A separator which tests the result of another separator. 
+   * It can be used to get the result of the separator without the contraction.
+   */
+  class SepTest : public Sep<SepTest>
+  {
+    public:
+
+      /**
+       * \brief Constructor for the separator.
+       * 
+       * \param s The separator to test.
+       */
+      template<typename S>
+        requires IsSepBaseOrPtr<S>
+      SepTest(const S& s)
+        : Sep<SepTest>(size_of(s)), _sep(s)
+      { }
+
+      /**
+       * \brief Separates the box. Both the inner and outer are either empty or the box itself.
+       * 
+       * \param x The box to separate.
+       */
+      BoxPair separate(const IntervalVector& x) const;
+
+    protected:
+
+      const Collection<SepBase> _sep;
+  };
+}
\ No newline at end of file
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index dff12a6f4..acb9f8f7d 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -99,6 +99,7 @@ list(APPEND SRC_TESTS # listing files without extension
   core/separators/codac2_tests_SepPolygon
   core/separators/codac2_tests_SepProj
   core/separators/codac2_tests_SepQInter
+  core/separators/codac2_tests_SepTest
   core/separators/codac2_tests_SepTransform
   core/separators/codac2_tests_SepUnion
   core/separators/codac2_tests_SepVisible
diff --git a/tests/core/separators/codac2_tests_SepTest.cpp b/tests/core/separators/codac2_tests_SepTest.cpp
new file mode 100644
index 000000000..c3b0949df
--- /dev/null
+++ b/tests/core/separators/codac2_tests_SepTest.cpp
@@ -0,0 +1,40 @@
+/** 
+ *  Codac tests
+ * ----------------------------------------------------------------------------
+ *  \date       2026
+ *  \author     Maël Godard
+ *  \copyright  Copyright 2024 Codac Team
+ *  \license    GNU Lesser General Public License (LGPL)
+ */
+
+#include <catch2/catch_test_macros.hpp>
+#include <codac2_SepTest.h>
+#include <codac2_Approx.h>
+#include <codac2_SepWrapper.h>
+
+using namespace std;
+using namespace codac2;
+
+
+TEST_CASE("SepTest")
+{
+  IntervalVector X ({{1,3},{2,8},{-1,1}});
+  SepWrapper<IntervalVector> sep_wrapper (X);
+  SepTest sep_test (sep_wrapper);
+
+  IntervalVector x1 ({{1.5,2.5},{2.5,7.5},{-0.5,0.5}});
+  IntervalVector x2 ({{10,11},{10,11},{10,11}});
+  IntervalVector x3 ({{1,3},{2,8},{-1,1}});
+
+  BoxPair xs = sep_test.separate(x1);
+  CHECK(xs.inner==IntervalVector::empty(3));
+  CHECK(xs.outer==x1);
+
+  xs = sep_test.separate(x2);
+  CHECK(xs.inner==x2);
+  CHECK(xs.outer==IntervalVector::empty(3));
+
+  xs = sep_test.separate(x3);
+  CHECK(xs.inner==x3);
+  CHECK(xs.outer==x3);
+}
\ No newline at end of file
diff --git a/tests/core/separators/codac2_tests_SepTest.py b/tests/core/separators/codac2_tests_SepTest.py
new file mode 100644
index 000000000..15a9f09d6
--- /dev/null
+++ b/tests/core/separators/codac2_tests_SepTest.py
@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+
+#  Codac tests
+# ----------------------------------------------------------------------------
+#  \date       2026
+#  \author     Maël Godard
+#  \copyright  Copyright 2024 Codac Team
+#  \license    GNU Lesser General Public License (LGPL)
+
+import unittest
+from codac import *
+
+class TestSepTest(unittest.TestCase):
+
+  def test_SepTest(self):
+
+    X = IntervalVector([[1,3],[2,8],[-1,1]])
+    sep_wrapper = SepWrapper_IntervalVector(X)
+    sep_test = SepTest(sep_wrapper)
+
+    x1 = IntervalVector([[1.5,2.5],[2.5,7.5],[-0.5,0.5]])
+    x2 = IntervalVector([[10,11],[10,11],[10,11]])
+    x3 = IntervalVector([[1,3],[2,8],[-1,1]])
+
+    inner,outer = sep_test.separate(x1)
+    self.assertTrue(inner==IntervalVector.empty(3))
+    self.assertTrue(outer==x1)
+
+    inner,outer = sep_test.separate(x2)
+    self.assertTrue(inner==x2)
+    self.assertTrue(outer==IntervalVector.empty(3))
+
+    inner,outer = sep_test.separate(x3)
+    self.assertTrue(inner==x3)
+    self.assertTrue(outer==x3)
+
+if __name__ ==  '__main__':
+  unittest.main()
\ No newline at end of file