Adding some test for issue kaitai-io/kaitai_struct#552.

formats/enum_to_i_class_border_1.ksy

@@ -0,0 +1,29 @@
+# https://github.com/kaitai-io/kaitai_struct/issues/552
+meta:
+  id: enum_to_i_class_border_1
+  endian: le
+  imports:
+    - enum_to_i_class_border_2
+
+seq:
+  - id:   pet_1
+    type: u4
+    enum: animal
+  - id:   pet_2
+    type: u4
+    enum: animal
+
+enums:
+  animal:
+    4:  dog
+    7:  cat
+    12: chicken
+
+instances:
+  some_dog:
+    value: 4
+    enum:  animal
+
+  checker:
+    pos:  0
+    type: enum_to_i_class_border_2(_root)

formats/enum_to_i_class_border_2.ksy

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+# https://github.com/kaitai-io/kaitai_struct/issues/552
+meta:
+  id: enum_to_i_class_border_2
+  endian: le
+  imports:
+    - enum_to_i_class_border_1
+
+params:
+  - id:   parent
+    type: enum_to_i_class_border_1
+
+instances:
+  is_dog:
+    value: parent.some_dog.to_i == 4

spec/ruby/enum_to_i_class_border_1_spec.rb

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+require 'enum_to_i_class_border_1'
+require 'enum_to_i_class_border_2'
+
+RSpec.describe EnumToIClassBorder1 do
+  it 'parses test properly' do
+    r = EnumToIClassBorder1.from_file('src/enum_0.bin')
+
+    expect(r.pet_1).to eq :animal_cat
+    expect(r.pet_2).to eq :animal_chicken
+    expect(r.checker.is_dog()).to eq true
+  end
+end