Strip extra TruffleRuby stacktrace lines from test output

This is a workaround to avoid a failure like this:

Integration::MinitestRedisTest
  test_junit_reporter                                             FAIL (17.45s)
        --- expected
        +++ actual
        @@ -47,6 +47,9 @@
         Failure:
         test_bar(BTest) [test/dummy_test.rb]:
         TypeError: String can't be coerced into Integer
        +    <internal:core> core/numeric.rb:200:in `math_coerce_error'
        +    <internal:core> core/numeric.rb:182:in `math_coerce'
        +    <internal:core> core/numeric.rb:221:in `redo_coerced'
             test/dummy_test.rb:37:in `+'
             test/dummy_test.rb:37:in `test_bar'
         ]]>
        /Users/rwstauner/src/github.com/Shopify/ci-queue/ruby/test/integration/minitest_redis_test.rb:499:in `test_junit_reporter'

Author: rwstauner

ruby/test/fixtures/test/backtrace_filters.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class BacktraceFilters
+  PATTERNS = [
+    # truffleruby has some extra lines before the usual ruby ones:
+    # "<internal:core> core/numeric.rb:182:in `math_coerce'"
+    %r{^<internal:},
+  ]
+
+  def initialize(original_filter)
+    @original_filter = original_filter
+  end
+
+  def add_filter(*args)
+    @original_filter.add_filter(*args)
+  end
+
+  def filter(backtrace)
+    backtrace = @original_filter.filter(backtrace) if @original_filter
+
+    backtrace.reject do |line|
+      PATTERNS.any? { |pattern| line.match?(pattern) }
+    end
+  end
+end

ruby/test/fixtures/test/test_helper.rb

@@ -6,3 +6,8 @@
 end
 
 require 'minitest/autorun'
+require_relative './backtrace_filters'
+
+Minitest.backtrace_filter = BacktraceFilters.new(
+  Minitest.backtrace_filter
+)

ruby/test/integration/minitest_redis_test.rb

@@ -496,6 +496,8 @@ def test_junit_reporter
       output = normalize(out.lines.last.strip)
       assert_equal 'Ran 9 tests, 6 assertions, 1 failures, 1 errors, 1 skips, 2 requeues in X.XXs', output
 
+      # NOTE: To filter the TypeError backtrace below see test/fixtures/test/backtrace_filters.rb
+
       assert_equal <<~XML, normalize_xml(File.read(@junit_path))
         <?xml version="1.1" encoding="UTF-8"?>
         <testsuites>