Add tests for large file downloads via the streaming interface

spec/bucket_store_integration_spec.rb

@@ -31,6 +31,10 @@
         end
       end
 
+      it "returns an empty bucket when no files are uploaded" do
+        expect(described_class.for(base_bucket_uri.to_s).list.to_a.size).to eq(0)
+      end
+
       it "has a consistent interface" do
         # Write 201 files
         file_list = []
@@ -75,9 +79,29 @@
         expect(described_class.for(base_bucket_uri.to_s).list.to_a.size).to eq(0)
       end
     end
+
+    context "using the streaming interface" do
+      it "supports large file downloads" do
+        # Upload a large file
+        large_file_content = "Z" * 1024 * 1024 * 10 # 10Mb
+        described_class.
+          for("#{base_bucket_uri}/large.txt").
+          upload!(large_file_content)
+
+        # Streaming downloads should return a chunked response
+        rebuilt_large_file =
+          described_class.for("#{base_bucket_uri}/large.txt").
+            stream.
+            download.
+            map { |_meta, chunk| chunk }.
+            join
+
+        expect(rebuilt_large_file.size).to eq(large_file_content.size)
+        expect(rebuilt_large_file).to eq(large_file_content)
+      end
+    end
   end
 
-  # We don't test GCS as there's no sensible way of running a local simulator
   include_examples "adapter integration", "inmemory://bucket"
   include_examples "adapter integration", "disk://bucket"
   include_examples "adapter integration", "s3://bucket"