Add unit tests for CheckedResult exception propagation

tests/run/cpp_exceptions_checked_result.pyx

+# mode: run
+# tag: cpp, cpp11
+
+cdef int raises(int success) nogil except ~:
+    if not success:
+        with gil:
+            raise ValueError("wrong value")
+    else:
+        return success
+
+def test_caught_exception():
+    """
+    >>> test_caught_exception()
+    1
+    """
+    cdef int r1
+    try:
+        with nogil:
+            r1 = raises(0)
+    except ValueError as e:
+        return 1
+    return 0
+
+def test_no_exception():
+    """
+    >>> test_no_exception()
+    1
+    """
+    cdef int r1
+    try:
+        with nogil:
+            r1 = raises(1)
+    except ValueError as e:
+        return 0
+    return r1
+
+
+cdef void void_raises(int success) nogil except ~:
+    if not success:
+        with gil:
+            raise ValueError("wrong value")
+
+def test_void_return_exception():
+    """
+    >>> test_void_return_exception()
+    1
+    """
+    try:
+        void_raises(0)
+        return 0
+    except ValueError as e:
+        return 1
+
+
+cdef cypclass Raises:
+    int raises(self, int success) nogil except ~:
+        if not success:
+            with gil:
+                raise ValueError("wrong value")
+        else:
+            return success
+
+def test_method_exception():
+    """
+    >>> test_method_exception()
+    1
+    """
+    cdef int r1
+    r = Raises()
+    try:
+        with nogil:
+            r1 = r.raises(0)
+    except ValueError as e:
+        return 1
+    return r1