Unexpected record order returned when using use_multiple_files and set_filenames

[paveg]

Add a test case to make it happen.
( The location where the test cases were added was small, so I'm just using aliases_spec.rb . )

diff --git a/spec/active_yaml/aliases_spec.rb b/spec/active_yaml/aliases_spec.rb
index d51d182..515d19f 100644
--- a/spec/active_yaml/aliases_spec.rb
+++ b/spec/active_yaml/aliases_spec.rb
@@ -68,21 +68,43 @@ describe ActiveYaml::Aliases do
     let(:coke) { model.where(:name => 'Coke').first }
     let(:schweppes) { model.where(:name => 'Schweppes').first }

-    before do
-      class MultipleFiles < ActiveYaml::Base
-        include ActiveYaml::Aliases
-        use_multiple_files
-        set_filenames 'array_products', 'array_products_2'
+    after do
+      Object.send :remove_const, :MultipleFiles
+    end
+
+    shared_examples 'returns correct data from both files' do
+      it do
+        expect(coke.flavor).to eq 'sweet'
+        expect(schweppes.flavor).to eq 'bitter'
+        binding.pry
+        expect(model.all.map(&:id)).to eq((1..5).to_a)
       end
     end

-    after do
-      Object.send :remove_const, :MultipleFiles
+    context 'when set_filenames correctly order' do
+      before do
+        class MultipleFiles < ActiveYaml::Base
+          include ActiveYaml::Aliases
+          use_multiple_files
+          files = %w[array_products array_products_2]
+          set_filenames *files
+        end
+      end
+
+      it_behaves_like 'returns correct data from both files'
     end

-    it 'returns correct data from both files' do
-      expect(coke.flavor).to eq 'sweet'
-      expect(schweppes.flavor).to eq 'bitter'
+    context 'when set_filenames incorrectly order' do
+      before do
+        class MultipleFiles < ActiveYaml::Base
+          include ActiveYaml::Aliases
+          use_multiple_files
+          files = %w[array_products_2 array_products]
+          set_filenames *files
+        end
+      end
+
+      it_behaves_like 'returns correct data from both files'
     end
   end
 end

And this test returns the following results.

Failures:

  1) ActiveYaml::Aliases Loading multiple files when set_filenames incorrectly order behaves like returns correct data from both files is expected to eq [1, 2, 3, 4, 5]
     Failure/Error: expect(model.all.map(&:id)).to eq((1..5).to_a)

       expected: [1, 2, 3, 4, 5]
            got: [5, 1, 2, 3, 4]

       (compared using ==)
     Shared Example Group: "returns correct data from both files" called from ./spec/active_yaml/aliases_spec.rb:106
     # ./spec/active_yaml/aliases_spec.rb:79:in `block (4 levels) in <top (required)>'

There are cases where there is no ID, but basically it would be more intuitive to return the result sorted by ID as the initial value of record access.