#434

backend/spec/services/counts_export_spec.rb

@@ -211,18 +211,37 @@ RSpec.describe 'Counts download acknowledgement' do
 end
 
 RSpec.describe CountsExportDownload::ResponseBody do
+  it 'survives Rails buffer enumeration without closing before the first byte' do
+    Dir.mktmpdir('counts-body-spec') do |directory|
+      path = File.join(directory, 'file')
+      payload = 'data' * 20_000
+      File.binwrite(path, payload)
+      states = []
+      source = ActionDispatch::Response::FileBody.new(path)
+      body = described_class.new(source) { |state| states << state; true }
+      response = ActionDispatch::Response.new
+      response.body = body
+      deferred = response.stream.to_ary
+      expect(states).to eq([])
+      expect(deferred.to_a.join).to eq(payload)
+      expect(states.count('started')).to eq(1)
+    end
+  end
+
   it 'acknowledges only after the first Rack yield and closes its bounded file body' do
     Dir.mktmpdir('counts-body-spec') do |directory|
       path = File.join(directory, 'file')
       File.binwrite(path, 'x' * (64 * 1024 + 3))
       states = []
-      body = described_class.new(path) { |state| states << state; true }
+      source = ActionDispatch::Response::FileBody.new(path)
+      body = described_class.new(source) { |state| states << state; true }
       chunks = []
       body.each do |chunk|
         expect(states).not_to include('started') if chunks.empty?
         chunks << chunk
       end
-      expect(chunks.map(&:bytesize)).to eq([64 * 1024, 3])
+      expect(chunks.join).to eq('x' * (64 * 1024 + 3))
+      expect(chunks.map(&:bytesize).max).to be <= 64 * 1024
       expect(states.count('started')).to eq(1)
       expect(body).not_to respond_to(:to_path)
       expect { body.close }.not_to raise_error
@@ -234,7 +253,8 @@ RSpec.describe CountsExportDownload::ResponseBody do
       path = File.join(directory, 'file')
       File.binwrite(path, 'data')
       states = []
-      body = described_class.new(path) { |state| states << state; true }
+      source = ActionDispatch::Response::FileBody.new(path)
+      body = described_class.new(source) { |state| states << state; true }
       expect { body.each { raise IOError, 'connection closed' } }.to raise_error(IOError)
       expect(states).to include('failed')
       expect(states).not_to include('started')