support/testing: add python-constantly tests

Add a simple test case to check the basic usage by creating a class with
two constants.

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/testing/tests/package/sample_python_constantly.py

@@ -0,0 +1,19 @@
+from constantly import ValueConstant, Values
+
+
+class RESULT(Values):
+    OK = ValueConstant(0)
+    FAIL = ValueConstant(-1)
+
+    @classmethod
+    def get(cls, rc):
+        if rc == 0:
+            return cls.OK
+        else:
+            return cls.FAIL
+
+
+print(list(RESULT.iterconstants()))
+assert(RESULT.OK < RESULT.FAIL)
+assert(RESULT.OK.value > RESULT.FAIL.value)
+assert(RESULT.get(-5) == RESULT.FAIL)