int datatype must not accept fractional floats

- added also test for this

Change-Id: I1c3ad92bc10131d6cd096496230222c999f0097e
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/22737
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

test/test_datatypes.py

@@ -109,8 +109,13 @@ def test_IntRange():
         dt('XX')
     with pytest.raises(ValueError):
         dt([19, 'X'])
+    with pytest.raises(ValueError):
+        dt(1.3)
+    with pytest.raises(ValueError):
+        dt('1.3')
     dt(1)
     dt(0)
+    dt('1')
     with pytest.raises(ProgrammingError):
         IntRange('xc', 'Yx')