Use randbytes in custom LCG random generator (#33557)

* It's internal and test only code, fine to change method name

Author: Abacn

.github/trigger_files/beam_PreCommit_Flink_Container.json

@@ -1,4 +1,4 @@
 {
     "comment": "Modify this file in a trivial way to cause this test suite to run",
-    "modification": 2
+    "modification": 3
 }

sdks/python/apache_beam/testing/fast_test_utils.pxd

@@ -29,5 +29,5 @@ cdef class LCGenerator(object):
   cpdef void seed_jdk(self, libc.stdint.uint64_t seed)
   cpdef libc.stdint.int32_t next_int(self)
   cpdef libc.stdint.uint32_t next_uint(self)
-  cpdef bytes rand_bytes(self, int length)
+  cpdef bytes randbytes(self, int length)
   cpdef double random_sample(self)

sdks/python/apache_beam/testing/fast_test_utils.pyx

@@ -44,7 +44,7 @@ cdef class LCGenerator(object):
     self.seed(self._seed)
     return <libc.stdint.uint32_t>(self._seed >> (self._bits - 32))
 
-  cpdef bytes rand_bytes(self, int length):
+  cpdef bytes randbytes(self, int length):
     cdef libc.stdint.int32_t ints = (length + 3) // 4
     cdef char* data = <char*>libc.stdlib.malloc(ints * 4)
     cdef libc.stdint.uint32_t value

sdks/python/apache_beam/testing/test_utils.py

@@ -273,7 +273,7 @@ def next_uint(self):
     self.seed(self._seed)
     return self._seed >> (self._bits - 32)
 
-  def rand_bytes(self, length):
+  def randbytes(self, length):
     """
     Get random bytes of given length.
 

sdks/python/apache_beam/testing/test_utils_test.py

@@ -107,7 +107,7 @@ def test_generator_seed_results(self):
     self.assertEqual(generator.next_int(), -1151252339)
     self.assertEqual(generator.next_uint(), 3745583449)
     self.assertAlmostEqual(generator.random_sample(), 0.375548, delta=1e-6)
-    self.assertEqual(generator.rand_bytes(10), b'\xa6\x8fW\xcb\xb1\xa88]dP')
+    self.assertEqual(generator.randbytes(10), b'\xa6\x8fW\xcb\xb1\xa88]dP')
 
   def test_generator_seed_jdk_results(self):
     generator = self.Generator()
@@ -119,7 +119,7 @@ def test_generator_seed_jdk_results(self):
     self.assertEqual(generator.next_int(), -1155869325)
     self.assertEqual(generator.next_uint(), 431529176)
     self.assertAlmostEqual(generator.random_sample(), 0.410081, delta=1e-6)
-    self.assertEqual(generator.rand_bytes(10), b'\x92\xf9Mh\xfc\xcc,5\xf0\xb8')
+    self.assertEqual(generator.randbytes(10), b'\x92\xf9Mh\xfc\xcc,5\xf0\xb8')
 
 
 try: