Fixed broken import in typecaster.h (#1181)

- Fixed the broken import _slsdet --> slsdet._slsdet caused by a previous upgrade
- Added tests that exercises the conversion from python to C++ and from C++ to python
- Python unit tests now run in CI (!)

python/src/duration.cpp

@@ -1,3 +1,4 @@
+#include <chrono>
 #include "py_headers.h"
 
 #include "DurationWrapper.h"
@@ -19,4 +20,25 @@ void init_duration(py::module &m) {
                << " count: " << self.count() << ")";
             return ss.str();
         });
+
+    m.def(
+        "test_return_DurationWrapper",
+        []() {
+            DurationWrapper t(1.3);
+            return t;
+        },
+        R"(
+          Test function to return a DurationWrapper object. Ensures that the automatic conversion in typecaster.h works.
+          )");
+
+    m.def(
+        "test_duration_to_ns",
+        [](const std::chrono::nanoseconds t) {
+            //Duration wrapper is used to be able to convert from time in python to chrono::nanoseconds
+            //return count to have something to test 
+            return t.count();
+        },
+        R"(
+          Test function convert DurationWrapper or number to chrono::ns. Ensures that the automatic conversion in typecaster.h works.
+          )"); // default value to test the default constructor
 }