diff --git a/lib/gitlab/ci/trace.rb b/lib/gitlab/ci/trace.rb
index b980e29e9c3..5b835bb669a 100644
--- a/lib/gitlab/ci/trace.rb
+++ b/lib/gitlab/ci/trace.rb
@@ -50,8 +50,6 @@ module Gitlab
       end
 
       def read
-        return unless exist?
-
         stream = Gitlab::Ci::Trace::Stream.new do
           if current_path
             File.open(current_path, "rb")
diff --git a/lib/gitlab/ci/trace/stream.rb b/lib/gitlab/ci/trace/stream.rb
index 8d9fb6ff0f1..757a8e2dc6a 100644
--- a/lib/gitlab/ci/trace/stream.rb
+++ b/lib/gitlab/ci/trace/stream.rb
@@ -14,9 +14,7 @@ module Gitlab
 
         def initialize
           @stream = yield
-          @stream.binmode
-          # Ci::Ansi2html::Converter would read from @stream directly
-          @stream.set_encoding(Encoding.default_external)
+          @stream.binmode if @stream
         end
 
         def valid?
@@ -58,12 +56,14 @@ module Gitlab
         end
 
         def html_with_state(state = nil)
+          set_encoding_for_ansi2html
           ::Ci::Ansi2html.convert(stream, state)
         end
 
         def html(last_lines: nil)
           text = raw(last_lines: last_lines)
           stream = StringIO.new(text)
+          set_encoding_for_ansi2html(stream)
           ::Ci::Ansi2html.convert(stream).html
         end
 
@@ -117,6 +117,11 @@ module Gitlab
 
           chunks.join.lines.last(last_lines).join
         end
+
+        def set_encoding_for_ansi2html(stream = @stream)
+          # Ci::Ansi2html::Converter would read from @stream directly
+          stream.set_encoding(Encoding.default_external)
+        end
       end
     end
   end
diff --git a/spec/lib/gitlab/ci/trace/stream_spec.rb b/spec/lib/gitlab/ci/trace/stream_spec.rb
index 6f5c9994f54..1602a4945ad 100644
--- a/spec/lib/gitlab/ci/trace/stream_spec.rb
+++ b/spec/lib/gitlab/ci/trace/stream_spec.rb
@@ -34,12 +34,12 @@ describe Gitlab::Ci::Trace::Stream do
     end
 
     context 'when the trace contains ANSI sequence and Unicode' do
-      let(:io) do
-        File.open(expand_fixture_path('trace/ansi-sequence-and-unicode'))
+      let(:stream) do
+        described_class.new do
+          File.open(expand_fixture_path('trace/ansi-sequence-and-unicode'))
+        end
       end
 
-      let(:stream) { described_class.new { io } }
-
       it 'forwards to the next linefeed, case 1' do
         stream.limit(7)
 
@@ -60,11 +60,11 @@ describe Gitlab::Ci::Trace::Stream do
 
       # See https://gitlab.com/gitlab-org/gitlab-ce/issues/30796
       it 'reads in binary, output as Encoding.default_external' do
-        stream.limit(29)
+        stream.limit(52)
 
-        result = io.read # Ci::Ansi2html::Converter would read with each_line
+        result = stream.html
 
-        expect(result).to eq("\e[01;32m許功蓋\e[0m\n")
+        expect(result.lines.first).to eq("ヾ(´༎ຶД༎ຶ`)ﾉ<br><span class=\"term-fg-green\">許功蓋</span><br>")
         expect(result.encoding).to eq(Encoding.default_external)
       end
     end