code: def test_cat_dim0_strides(self):
      i = Variable("i", 1, 5).bind(3)
      j = Variable("j", 1, 5).bind(3)
      k = Variable("k", 1, 5).bind(3)
      t = (
          Tensor.rand(3, 4)
          .reshape(i, 4)
          .cat(Tensor.rand(3, 4).reshape(j, 4), dim=0)
          .cat(Tensor.rand(3, 4).reshape(k, 4), dim=0)
      )
      st = t.lazydata.st
      assert st.shape == (i + j + k, 4)
      assert st.real_strides() == (4, 1)
      t = (
          Tensor.rand(3, 3)
          .reshape(i, 3)
          .cat(Tensor.rand(3, 3).reshape(i, 3), dim=0)
          .cat(Tensor.rand(3, 3), dim=0)
      )
      st = t.lazydata.st
      assert st.shape == (2 * i + 3, 3)
      assert st.real_strides() == (3, 1)
  
imports: import unittest
  from tinygrad.shape.shapetracker import ShapeTracker, View
  from tinygrad.shape.symbolic import Variable, NumNode
  from tinygrad.tensor import Tensor
label_desc: Use image node_id 3 for calling the TestSymbolic obj's underlying member method code with example usage: obj.test_cat_dim0_strides() without return types