tweaks

test/config_test.rb

@@ -9,6 +9,7 @@ class ConfigTest < Minitest::Test
     assert_in_delta 463.0, config.maximum_diameter("eight_piece"), 0.001
     assert_in_delta 1.6, config["shell"]["wall_mm"], 0.001
     assert_in_delta 0.8, config["shell"]["minimum_feature_mm"], 0.001
+    assert_equal "solid", config["shell"]["interior"]
     assert_in_delta 10.0, config["stand"]["base_clearance_mm"], 0.001
   end
 
@@ -32,4 +33,8 @@ class ConfigTest < Minitest::Test
       MoonModel::Config.new("stand" => { "base_clearance_mm" => -0.1 })
     end
   end
+
+  def test_rejects_unknown_interior_mode
+    assert_raises(ArgumentError) { MoonModel::Config.new("shell" => { "interior" => "foam" }) }
+  end
 end

test/generator_test.rb

@@ -21,6 +21,10 @@ class GeneratorTest < Minitest::Test
         assert_includes model, "<components>"
       end
       assert File.file?(File.join(result[:output_dir], "manifest.md"))
+      manifest = File.read(File.join(result[:output_dir], "manifest.md"))
+      assembly = File.read(File.join(result[:output_dir], "ASSEMBLY.md"))
+      assert_includes manifest, "Interior: solid slicer volume"
+      assert_includes assembly, "no internal cavity supports are required"
       assert_in_delta 40.0, result[:statistics]["final_envelope_mm"], 0.01
     end
   end

test/geometry_test.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class GeometryTest < Minitest::Test
+  def setup
+    @data = MoonModel::DataSet.new
+  end
+
+  def test_solid_one_piece_is_a_closed_outer_volume_without_inner_surface
+    solid = structure("solid")
+    hollow = structure("hollow")
+
+    assert solid.valid?
+    assert_manifold solid
+    assert_equal hollow.triangles.length / 2, solid.triangles.length
+    assert_equal hollow.vertices.length / 2, solid.vertices.length
+  end
+
+  def test_solid_single_color_grid_remains_manifold
+    config = config_for("solid", "grid" => { "enabled" => true, "depth_mm" => 0.4 })
+    mesh = MoonModel::Geometry.build(config, @data).parts.first[:meshes].first
+
+    assert mesh.valid?
+    assert_manifold mesh
+  end
+
+  def test_segmented_output_is_hollow_even_when_solid_is_requested
+    config = config_for("solid", "purpose" => "box", "assembly" => "eight_piece")
+    result = MoonModel::Geometry.build(config, @data)
+
+    assert result.segmented?
+    assert_equal "hollow", result.statistics["interior"]
+  end
+
+  private
+
+  def structure(interior)
+    MoonModel::Geometry.build(config_for(interior), @data).parts.first[:meshes].first
+  end
+
+  def config_for(interior, extra = {})
+    MoonModel::Config.new({
+      "size" => { "value" => 40 },
+      "shell" => { "interior" => interior },
+      "resolution" => { "longitude_segments" => 24 }
+    }.merge(extra))
+  end
+
+  def assert_manifold(mesh)
+    edge_uses = Hash.new(0)
+    mesh.triangles.each do |triangle|
+      triangle.each_index do |index|
+        edge_uses[[triangle[index], triangle[(index + 1) % 3]].sort] += 1
+      end
+    end
+    assert edge_uses.values.all? { |count| count == 2 }, "every edge must belong to exactly two faces"
+  end
+end

test/sizing_test.rb

@@ -11,11 +11,20 @@ class SizingTest < Minitest::Test
     MoonModel::Config.new(
       "size" => { "input" => "diameter", "value" => 8.0, "unit" => "in", "meaning" => "datum" },
       "vertical_exaggeration" => exaggeration,
-      "assembly" => assembly,
+      "assembly" => assembly, "shell" => { "interior" => "hollow" },
       "resolution" => { "longitude_segments" => 48 }
     )
   end
 
+
+  def test_solid_one_piece_allows_more_relief_before_radial_collapse
+    hollow = datum_config(1, assembly: "one_piece")
+    solid = MoonModel::Config.new(hollow.to_h.merge("shell" => hollow["shell"].merge("interior" => "solid")))
+
+    assert_operator MoonModel::Sizing.maximum_safe_exaggeration(solid, @data), :>,
+                    MoonModel::Sizing.maximum_safe_exaggeration(hollow, @data)
+  end
+
   def test_eight_inch_relief_uses_consistent_units
     one = MoonModel::Sizing.calculate(datum_config(1), @data)
     ten = MoonModel::Sizing.calculate(datum_config(10), @data)

test/wizard_test.rb

@@ -69,6 +69,18 @@ class WizardTest < Minitest::Test
     assert_includes output.string, "waive the recommended terrain safety margin"
   end
 
+  def test_one_piece_interior_choice_can_select_hollow
+    input = StringIO.new("\n\n\n\nn\n\n\n")
+    output = StringIO.new
+    wizard = MoonModel::Wizard.new(io: HighLine.new(input, output), data_set: MoonModel::DataSet.new)
+    values = { "printer" => MoonModel::Config::X2D.dup, "purpose" => "display", "assembly" => "auto" }
+
+    wizard.send(:sizing, values)
+
+    assert_equal "hollow", values.dig("shell", "interior")
+    assert_includes output.string, "use slicer-controlled infill instead of a hollow cavity"
+  end
+
   private
 
   def ask_yes_no(input, default)