1 files changed, 79 insertions, 0 deletions
diff --git a/spec/initializers/rack_multipart_patch_spec.rb b/spec/initializers/rack_multipart_patch_spec.rb
new file mode 100644
index 00000000000..862fdc7901b
--- /dev/null
+++ b/spec/initializers/rack_multipart_patch_spec.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Rack::Multipart do # rubocop:disable RSpec/FilePath
+  def multipart_fixture(name, length, boundary = "AaB03x")
+    data = <<EOF
+--#{boundary}\r
+content-disposition: form-data; name="reply"\r
+\r
+yes\r
+--#{boundary}\r
+content-disposition: form-data; name="fileupload"; filename="dj.jpg"\r
+Content-Type: image/jpeg\r
+Content-Transfer-Encoding: base64\r
+\r
+/9j/4AAQSkZJRgABAQAAAQABAAD//gA+Q1JFQVRPUjogZ2QtanBlZyB2MS4wICh1c2luZyBJSkcg\r
+--#{boundary}--\r
+EOF
+
+    type = %(multipart/form-data; boundary=#{boundary})
+
+    length ||= data.bytesize
+
+    {
+      "CONTENT_TYPE" => type,
+      "CONTENT_LENGTH" => length.to_s,
+      input: StringIO.new(data)
+    }
+  end
+
+  context 'with Content-Length under the limit' do
+    it 'extracts multipart message' do
+      env = Rack::MockRequest.env_for("/", multipart_fixture(:text, nil))
+
+      expect(described_class).to receive(:log_large_multipart?).and_call_original
+      expect(described_class).not_to receive(:log_multipart_warning)
+      params = described_class.parse_multipart(env)
+
+      expect(params.keys).to include(*%w(reply fileupload))
+    end
+  end
+
+  context 'with Content-Length over the limit' do
+    shared_examples 'logs multipart message' do
+      it 'extracts multipart message' do
+        env = Rack::MockRequest.env_for("/", multipart_fixture(:text, length))
+
+        expect(described_class).to receive(:log_large_multipart?).and_return(true)
+        expect(described_class).to receive(:log_multipart_warning).and_call_original
+        expect(described_class).to receive(:log_warn).with({
+                                                             message: 'Large multipart body detected',
+                                                             path: '/',
+                                                             content_length: anything,
+                                                             correlation_id: anything
+                                                           })
+        params = described_class.parse_multipart(env)
+
+        expect(params.keys).to include(*%w(reply fileupload))
+      end
+    end
+
+    context 'from environment' do
+      let(:length) { 1001 }
+
+      before do
+        stub_env('RACK_MULTIPART_LOGGING_BYTES', 1000)
+      end
+
+      it_behaves_like 'logs multipart message'
+    end
+
+    context 'default limit' do
+      let(:length) { 100_000_001 }
+
+      it_behaves_like 'logs multipart message'
+    end
+  end
+end