1 files changed, 16 insertions, 1 deletions
diff --git a/spec/lib/gitlab/ci/trace/stream_spec.rb b/spec/lib/gitlab/ci/trace/stream_spec.rb
index 03f040f4465..2bd2aab829e 100644
--- a/spec/lib/gitlab/ci/trace/stream_spec.rb
+++ b/spec/lib/gitlab/ci/trace/stream_spec.rb
@@ -71,9 +71,13 @@ describe Gitlab::Ci::Trace::Stream do
   end
 
   describe '#append' do
+    let(:tempfile) { Tempfile.new }
+
     let(:stream) do
       described_class.new do
-        StringIO.new("12345678")
+        tempfile.write("12345678")
+        tempfile.rewind
+        tempfile
       end
     end
 
@@ -84,6 +88,17 @@ describe Gitlab::Ci::Trace::Stream do
       expect(stream.size).to eq(6)
       expect(stream.raw).to eq("123489")
     end
+
+    it 'appends in binary mode' do
+      '😺'.force_encoding('ASCII-8BIT').each_char.with_index do |byte, offset|
+        stream.append(byte, offset)
+      end
+
+      stream.seek(0)
+
+      expect(stream.size).to eq(4)
+      expect(stream.raw).to eq('😺')
+    end
   end
 
   describe '#set' do