diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 482d9175..d53a35fc 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -391,6 +391,9 @@ add_test(testScale testScale)
 add_executable(testrange testrange.cpp)
 add_test(testrange testrange)
 
+add_executable(testrange_constexpr testrange_constexpr.cpp)
+add_test(testrange_constexpr testrange_constexpr)
+
 # Test the colour mapping
 add_executable(testColourMap testColourMap.cpp)
 add_test(testColourMap testColourMap)
diff --git a/tests/testrange_constexpr.cpp b/tests/testrange_constexpr.cpp
new file mode 100644
index 00000000..abc9393f
--- /dev/null
+++ b/tests/testrange_constexpr.cpp
@@ -0,0 +1,74 @@
+#include <iostream>
+#include <morph/range.h>
+#include <morph/mathconst.h>
+
+constexpr morph::range<float> test_update()
+{
+    morph::range<float> r{2.0f, 4.0f};
+    r.update (1.0f);
+    r.update (5.0f);
+    return r;
+}
+
+constexpr morph::range<float> test_update_and_search_init()
+{
+    morph::range<float> r;
+    r.search_init();
+    r.update (1.0f);
+    r.update (5.0f);
+    return r;
+}
+
+constexpr bool test_update_and_includes()
+{
+    morph::range<float> r(2.0f, 4.0f); // also test 2 arg constructor
+    r.update (1.0f);
+    r.update (5.0f);
+    int rtn = 0;
+    if (r.includes (3.0f) == false) { --rtn; }
+    if (r.includes (0.5f) == true) { --rtn; }
+
+    return (rtn == 0 ? true : false);
+}
+
+constexpr float test_span()
+{
+    morph::range<float> r{2.0f, 4.0f};
+    return r.span();
+}
+
+constexpr float test_set()
+{
+    morph::range<float> r;
+    r.set (56.0f, 59.0f);
+    return r.span();
+}
+
+int main()
+{
+    int rtn = 0;
+
+    constexpr morph::range<float> r1 = test_update();
+    if (r1.min == 1.0f && r1.max == 5.0f) {
+        // good
+    } else {
+        --rtn;
+    }
+    constexpr morph::range<float> r2 = test_update_and_search_init();
+    if (r2.min == 1.0f && r2.max == 5.0f) {
+        // good
+    } else {
+        --rtn;
+    }
+    constexpr bool tres = test_update_and_includes();
+    if (tres == false) { --rtn; }
+
+    constexpr float spn = test_span();
+    if (spn != 2.0f) { --rtn; }
+
+    constexpr float spn2 = test_set();
+    if (spn2 != 3.0f) { --rtn; }
+
+    std::cout << "Test " << (rtn == 0 ? "Passed" : "Failed") << std::endl;
+    return rtn;
+}