Add test for loading split mesh with FileMeshGenerator, refs idaholab…

…#18635

test/tests/mesh/splitting/extrude_from_split.i

@@ -0,0 +1,68 @@
+[Mesh]
+  [read]
+    type = FileMeshGenerator
+    file = 'foo.cpr'
+  []
+  [extrude]
+    type = FancyExtruderGenerator
+    input = read
+    heights = '1 2 3'
+    num_layers = '1 2 3'
+    direction = '0 0 1'
+    bottom_sideset = '4'
+    top_sideset = '5'
+  []
+[]
+
+[Variables]
+  [u]
+  []
+[]
+
+[Kernels]
+  [diff]
+    type = Diffusion
+    variable = u
+  []
+[]
+
+[BCs]
+  [left]
+    type = DirichletBC
+    variable = u
+    boundary = 'left'
+    value = 0
+  []
+  [right]
+    type = DirichletBC
+    variable = u
+    boundary = 'right'
+    value = 1
+  []
+[]
+
+[Executioner]
+  type = Steady
+  solve_type = PJFNK
+  petsc_options_iname = '-pc_type -pc_hypre_type'
+  petsc_options_value = 'hypre boomeramg'
+[]
+
+[Outputs]
+  exodus = true
+[]
+
+[AuxVariables]
+  [pid]
+    family = MONOMIAL
+    order = CONSTANT
+  []
+[]
+
+[AuxKernels]
+  [pid_aux]
+    type = ProcessorIDAux
+    variable = pid
+    execute_on = 'INITIAL'
+  []
+[]

test/tests/mesh/splitting/tests

@@ -134,4 +134,21 @@
     requirement = 'Splitting meshes from a generated mesh should work with custom partitioners.'
     mesh_mode = REPLICATED
   []
+
+  [meshgenerators_acting_on_split]
+    type = 'Exodiff'
+    input = 'extrude_from_split.i'
+    cli_args = '--mesh-only'
+    mesh_mode = DISTRIBUTED
+    exodiff = 'extrude_from_split_in.e'
+    recover = false
+
+    min_parallel = 3
+    max_parallel = 3
+    prereq = 'use_split'
+
+    issues = '#18635'
+    design = 'Mesh/splitting.md FileMeshGenerator.md'
+    requirement = 'The system should be able to load a pre-split mesh and perform additional mesh generation on it.'
+  []
 []