Add new test that input a field variable into `EquilibriumBC/enclosur…

…e_var`

(Close. #134)
(Ref. #133)

test/tests/bcs/EquilibriumBC/equilibriumBC.i

@@ -0,0 +1,82 @@
+# Simple test to ensure that EquilibriumBC's enclosure_var can take in a field variable
+
+[Mesh]
+  type = GeneratedMesh
+  dim = 1
+[]
+
+[Variables]
+  [u]
+  []
+[]
+
+[AuxVariables]
+  [v]
+    initial_condition = 1
+  []
+[]
+
+[Kernels]
+  [diff]
+    type = MatDiffusion
+    variable = u
+    diffusivity = 1
+  []
+  [time]
+    type = TimeDerivative
+    variable = u
+  []
+[]
+
+[BCs]
+  [right]
+    type = DirichletBC
+    value = 0
+    variable = u
+    boundary = 'right'
+  []
+  [left]
+    type = EquilibriumBC
+    variable = u
+    enclosure_var = v
+    boundary = 'left'
+    Ko = 1
+    temperature = 1
+  []
+[]
+
+[Postprocessors]
+  [flux_surface_left]
+    type = SideDiffusiveFluxIntegral
+    variable = u
+    diffusivity = 1
+    boundary = 'left'
+    execute_on = 'initial nonlinear linear timestep_end'
+  []
+[]
+
+[Executioner]
+  type = Transient
+  dt = .1
+  num_steps = 1
+  solve_type = PJFNK
+  automatic_scaling = true
+  dtmin = .1
+  l_max_its = 30
+  nl_max_its = 5
+  petsc_options = '-snes_converged_reason -ksp_monitor_true_residual'
+  petsc_options_iname = '-pc_type -mat_mffd_err'
+  petsc_options_value = 'lu       1e-5'
+  line_search = 'bt'
+  scheme = 'bdf2'
+  timestep_tolerance = 1e-8
+[]
+
+[Outputs]
+  file_base = equilibriumBC_out
+  perf_graph = true
+  [csv]
+    type = CSV
+    execute_on = 'initial timestep_end'
+  []
+[]

test/tests/bcs/EquilibriumBC/gold/equilibriumBC_out.csv

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+time,flux_surface_left
+0,0
+0.1,-1

test/tests/bcs/EquilibriumBC/tests

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+[Tests]
+  [equilibriumBC_fiel_variable]
+    type = 'CSVDiff'
+    input = 'equilibriumBC.i'
+    csvdiff = 'equilibriumBC_out.csv'
+    issues = '#134'
+    design = 'EquilibriumBC.md'
+    requirement = 'The system shall compute the flux imposed by EquilibriumBC when a field variable is used for the enclosure variable.'
+  []
+[]