[CodeStyle][UP012] Unnecessary call to encode as UTF-8 (#51994)

pyproject.toml

@@ -46,6 +46,7 @@ select = [
     "UP008",
     "UP010",
     "UP011",
+    "UP012",
     "UP013",
     "UP014",
     "UP017",

python/paddle/fluid/tests/unittests/test_nan_inf.py

@@ -47,7 +47,7 @@ class TestNanInf(unittest.TestCase):
         print(err)
 
         # in python3, type(out+err) is 'bytes', need use encode
-        assert (out + err).find('There are NAN or INF'.encode()) != -1
+        assert (out + err).find(b'There are NAN or INF') != -1
 
     def test_nan_inf_in_static_mode(self):
         self._python_interp += " check_nan_inf_base.py"

tools/test_print_signatures.py

@@ -67,7 +67,7 @@ class Test_is_primitive(unittest.TestCase):
         self.assertTrue(is_primitive(2))
         self.assertTrue(is_primitive(2.1))
         self.assertTrue(is_primitive("2.1.1"))
-        self.assertFalse(is_primitive("hello paddle".encode('UTF-8')))
+        self.assertFalse(is_primitive(b"hello paddle"))
         self.assertFalse(is_primitive(1j))
         self.assertTrue(is_primitive(True))