test(backtrace_cleaner): add #clean specs

lib/convenient_service/logger.rb

@@ -14,6 +14,9 @@ module ConvenientService
   ##
   # @internal
   #   TODO: Custom matcher to track log messages.
+  #   TODO: Fallback for logging methods. Just like with `#clean` in backtrace cleaner.
+  #   TODO: Highlight vertical bars.
+  #   TODO: Highlight tag brackets.
   #
   class Logger < ::Logger
     include ::Singleton
@@ -92,7 +95,7 @@ def colored_formatter
     #
     #   NOTE: Early return is NOT used, since it is NOT possible to return custom values from `writer` methods.
     #
-    #   NOTE: `Warning.warn` is chosen over `Kernel.warn` in order to have a simple to track delegation from RSpec.
+    #   NOTE: `Warning.warn` is chosen over `Kernel.warn` in order to have a simple way to track delegation from RSpec.
     #   - https://ruby-doc.org/core-2.7.0/Warning.html#method-i-warn
     #
     # TODO: Tag/prefix for all Convenient Service logs.

lib/convenient_service/support/backtrace_cleaner.rb

@@ -83,6 +83,35 @@ def initialize(...)
       def add_convenient_service_silencer
         add_silencer { |line| /convenient_service/.match?(line) }
       end
+
+      ##
+      # Works exactly in the same way as the original `clean`, except it falls back to an empty array in case of any exceptions inside filters or silencers.
+      # Also returns an empty array, when `backtrace` is `nil`.
+      #
+      # @return [Array<String>]
+      #
+      # @see https://api.rubyonrails.org/classes/ActiveSupport/BacktraceCleaner.html#method-i-clean
+      #
+      # @internal
+      #   IMPORTANT: Sometimes `exception.backtrace` can be `nil`.
+      #   - https://blog.kalina.tech/2019/04/exception-without-backtrace-in-ruby.html
+      #   - https://github.com/jruby/jruby/issues/4467
+      #
+      def clean(backtrace, *args)
+        if backtrace.nil?
+          ::ConvenientService.logger.warn { "[BacktraceCleaner] `nil` backtrace | Empty array is used as fallback" }
+
+          return []
+        end
+
+        begin
+          super
+        rescue
+          ::ConvenientService.logger.warn { "[BacktraceCleaner] Some filter or silencer is broken | Original backtrace is used as fallback" }
+
+          backtrace
+        end
+      end
     end
   end
 end

spec/lib/convenient_service/support/backtrace_cleaner_spec.rb

@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+require "convenient_service"
+
+# rubocop:disable RSpec/NestedGroups, RSpec/MultipleMemoizedHelpers
+RSpec.describe ConvenientService::Support::BacktraceCleaner do
+  ##
+  # example_group "class methods" do
+  #   ##
+  #   # NOTE: `.new` is tested indirectly by `add_convenient_service_silencer`.
+  #   #
+  #   describe ".new" do
+  #     # ...
+  #   end
+  # end
+  #
+  example_group "instance methods" do
+    let(:backtrace_cleaner) { described_class.new }
+    let(:backtrace) { ["foo", "convenient_service"] }
+
+    describe "#clean" do
+      it "calls super" do
+        backtrace_cleaner.clean(backtrace)
+
+        expect(backtrace_cleaner.clean(backtrace)).to eq(["foo"])
+      end
+
+      context "when backtrace is `nil`" do
+        let(:backtrace) { nil }
+
+        it "returns empty array" do
+          expect(backtrace_cleaner.clean(backtrace)).to eq([])
+        end
+
+        ##
+        # TODO: `it "logs warning message"`.
+        #
+      end
+
+      context "when exception is raised" do
+        let(:backtrace) { Enumerator.new { raise ArgumentError } }
+
+        it "returns original backtrace" do
+          expect(backtrace_cleaner.clean(backtrace)).to eq(backtrace)
+        end
+
+        ##
+        # TODO: `it "logs warning message"`.
+        #
+      end
+    end
+  end
+end
+# rubocop:enable RSpec/NestedGroups, RSpec/MultipleMemoizedHelpers