diff --git a/spec/tooling/lib/tooling/find_tests_spec.rb b/spec/tooling/lib/tooling/find_tests_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..997d9d9a746dd6bac36e08cd372abebffb8e0471
--- /dev/null
+++ b/spec/tooling/lib/tooling/find_tests_spec.rb
@@ -0,0 +1,155 @@
+# frozen_string_literal: true
+
+require 'tempfile'
+require_relative '../../../../tooling/lib/tooling/find_tests'
+require_relative '../../../support/helpers/stub_env'
+
+RSpec.describe Tooling::FindTests, feature_category: :tooling do
+ include StubENV
+
+ attr_accessor :changes_file, :matching_tests_paths
+
+ let(:instance) { described_class.new(changes_file, matching_tests_paths) }
+ let(:mock_test_file_finder) { instance_double(TestFileFinder::FileFinder) }
+ let(:new_matching_tests) { ["new_matching_spec.rb"] }
+ let(:changes_file_content) { "changed_file1 changed_file2" }
+ let(:matching_tests_paths_content) { "previously_matching_spec.rb" }
+
+ around do |example|
+ self.changes_file = Tempfile.new('changes')
+ self.matching_tests_paths = Tempfile.new('matching_tests')
+
+ # See https://ruby-doc.org/stdlib-1.9.3/libdoc/tempfile/rdoc/
+ # Tempfile.html#class-Tempfile-label-Explicit+close
+ begin
+ example.run
+ ensure
+ changes_file.close
+ matching_tests_paths.close
+ changes_file.unlink
+ matching_tests_paths.unlink
+ end
+ end
+
+ before do
+ allow(mock_test_file_finder).to receive(:use)
+ allow(mock_test_file_finder).to receive(:test_files).and_return(new_matching_tests)
+ allow(TestFileFinder::FileFinder).to receive(:new).and_return(mock_test_file_finder)
+
+ stub_env(
+ 'RSPEC_TESTS_MAPPING_ENABLED' => nil,
+ 'RSPEC_TESTS_MAPPING_PATH' => '/tmp/does-not-exist.out'
+ )
+
+ # We write into the temp files initially, to later check how the code modified those files
+ File.write(changes_file, changes_file_content)
+ File.write(matching_tests_paths, matching_tests_paths_content)
+ end
+
+ describe '#execute' do
+ subject { instance.execute }
+
+ context 'when the matching_tests_paths file does not exist' do
+ before do
+ allow(File).to receive(:exist?).and_return(false)
+ allow(File).to receive(:write).with(matching_tests_paths, any_args)
+ end
+
+ it 'creates an empty file' do
+ expect(File).to receive(:write).with(matching_tests_paths, '')
+
+ subject
+ end
+ end
+
+ context 'when the matching_tests_paths file already exists' do
+ it 'does not create an empty file' do
+ expect(File).not_to receive(:write).with(matching_tests_paths, '')
+
+ subject
+ end
+ end
+
+ it 'does not modify the content of the input file' do
+ expect { subject }.not_to change { File.read(changes_file) }
+ end
+
+ it 'does not overwrite the output file' do
+ expect { subject }.to change { File.read(matching_tests_paths) }
+ .from(matching_tests_paths_content)
+ .to("#{matching_tests_paths_content} #{new_matching_tests.uniq.join(' ')}")
+ end
+
+ it 'loads the tests.yml file with a pattern matching mapping' do
+ expect(TestFileFinder::MappingStrategies::PatternMatching).to receive(:load).with('tests.yml')
+
+ subject
+ end
+
+ context 'when RSPEC_TESTS_MAPPING_ENABLED env variable is set' do
+ before do
+ stub_env(
+ 'RSPEC_TESTS_MAPPING_ENABLED' => 'true',
+ 'RSPEC_TESTS_MAPPING_PATH' => 'crystalball-test/mapping.json'
+ )
+ end
+
+ it 'loads the direct matching pattern file' do
+ expect(TestFileFinder::MappingStrategies::DirectMatching)
+ .to receive(:load_json)
+ .with('crystalball-test/mapping.json')
+
+ subject
+ end
+ end
+
+ context 'when RSPEC_TESTS_MAPPING_ENABLED env variable is not set' do
+ let(:rspec_tests_mapping_enabled) { '' }
+
+ before do
+ stub_env(
+ 'RSPEC_TESTS_MAPPING_ENABLED' => rspec_tests_mapping_enabled,
+ 'RSPEC_TESTS_MAPPING_PATH' => rspec_tests_mapping_path
+ )
+ end
+
+ context 'when RSPEC_TESTS_MAPPING_PATH is set' do
+ let(:rspec_tests_mapping_path) { 'crystalball-test/mapping.json' }
+
+ it 'does not load the direct matching pattern file' do
+ expect(TestFileFinder::MappingStrategies::DirectMatching).not_to receive(:load_json)
+
+ subject
+ end
+ end
+
+ context 'when RSPEC_TESTS_MAPPING_PATH is not set' do
+ let(:rspec_tests_mapping_path) { nil }
+
+ it 'does not load the direct matching pattern file' do
+ expect(TestFileFinder::MappingStrategies::DirectMatching).not_to receive(:load_json)
+
+ subject
+ end
+ end
+ end
+
+ context 'when the same spec is matching multiple times' do
+ let(:new_matching_tests) do
+ [
+ "new_matching_spec.rb",
+ "duplicate_spec.rb",
+ "duplicate_spec.rb"
+ ]
+ end
+
+ it 'writes uniquely matching specs to the output' do
+ subject
+
+ expect(File.read(matching_tests_paths).split(' ')).to match_array(
+ matching_tests_paths_content.split(' ') + new_matching_tests.uniq
+ )
+ end
+ end
+ end
+end
diff --git a/tooling/bin/find_tests b/tooling/bin/find_tests
index 33834064f364bfb955c3a9a58bb5c80ade91e37d..31afa4d598bde65770acbd2858ba8922c4fc999a 100755
--- a/tooling/bin/find_tests
+++ b/tooling/bin/find_tests
@@ -1,19 +1,9 @@
#!/usr/bin/env ruby
# frozen_string_literal: true
-require 'test_file_finder'
+require_relative '../lib/tooling/find_tests'
-changes = ARGV.shift
-output_file = ARGV.shift
+changes_file = ARGV.shift
+matching_tests_paths = ARGV.shift
-changed_files = File.read(changes).split(' ')
-
-tff = TestFileFinder::FileFinder.new(paths: changed_files).tap do |file_finder|
- file_finder.use TestFileFinder::MappingStrategies::PatternMatching.load('tests.yml')
-
- if ENV['RSPEC_TESTS_MAPPING_ENABLED']
- file_finder.use TestFileFinder::MappingStrategies::DirectMatching.load_json(ENV['RSPEC_TESTS_MAPPING_PATH'])
- end
-end
-
-File.write(output_file, tff.test_files.uniq.join(' '))
+Tooling::FindTests.new(changes_file, matching_tests_paths).execute
diff --git a/tooling/lib/tooling/find_tests.rb b/tooling/lib/tooling/find_tests.rb
new file mode 100644
index 0000000000000000000000000000000000000000..4acbb5fcd6aea5a4e5f6da336f02aa4340ade011
--- /dev/null
+++ b/tooling/lib/tooling/find_tests.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require 'test_file_finder'
+
+module Tooling
+ class FindTests
+ def initialize(changes_file, matching_tests_paths)
+ @matching_tests_paths = matching_tests_paths
+ @changed_files = File.read(changes_file).split(' ')
+
+ File.write(matching_tests_paths, '') unless File.exist?(matching_tests_paths)
+
+ @matching_tests = File.read(matching_tests_paths).split(' ')
+ end
+
+ def execute
+ tff = TestFileFinder::FileFinder.new(paths: changed_files).tap do |file_finder|
+ file_finder.use TestFileFinder::MappingStrategies::PatternMatching.load('tests.yml')
+
+ if ENV['RSPEC_TESTS_MAPPING_ENABLED'] == 'true'
+ file_finder.use TestFileFinder::MappingStrategies::DirectMatching.load_json(ENV['RSPEC_TESTS_MAPPING_PATH'])
+ end
+ end
+
+ new_matching_tests = tff.test_files.uniq
+ File.write(matching_tests_paths, (matching_tests + new_matching_tests).join(' '))
+ end
+
+ private
+
+ attr_reader :changed_files, :matching_tests, :matching_tests_paths
+ end
+end