code: def test_alloc(self):
      p1 = self.pool.malloc(1000)
      p2 = self.pool.malloc(1000)
      p3 = self.pool.malloc(2000)
      assert p1.ptr != p2.ptr
      assert p1.ptr != p3.ptr
      assert p2.ptr != p3.ptr
  
imports: import unittest
  from cupy.cuda import pinned_memory
label_desc: Use image node_id 2 for calling the TestSingleDeviceMemoryPool obj's underlying member method code with example usage: obj.test_alloc() without return types