1 files changed, 38 insertions, 13 deletions
diff --git a/spec/tooling/lib/tooling/predictive_tests_spec.rb b/spec/tooling/lib/tooling/predictive_tests_spec.rb
index 79554037c48..b82364fe6f6 100644
--- a/spec/tooling/lib/tooling/predictive_tests_spec.rb
+++ b/spec/tooling/lib/tooling/predictive_tests_spec.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'tempfile'
+require 'fileutils'
 require_relative '../../../../tooling/lib/tooling/predictive_tests'
 require_relative '../../../support/helpers/stub_env'
 
@@ -9,11 +10,14 @@ RSpec.describe Tooling::PredictiveTests, feature_category: :tooling do
 
   let(:instance)                       { described_class.new }
   let(:matching_tests_initial_content) { 'initial_matching_spec' }
+  let(:fixtures_mapping_content)       { '{}' }
 
-  attr_accessor :changed_files, :fixtures_mapping, :matching_js_files, :matching_tests, :views_with_partials
+  attr_accessor :changed_files, :changed_files_path, :fixtures_mapping,
+    :matching_js_files, :matching_tests, :views_with_partials
 
   around do |example|
     self.changed_files       = Tempfile.new('test-folder/changed_files.txt')
+    self.changed_files_path  = changed_files.path
     self.fixtures_mapping    = Tempfile.new('test-folder/fixtures_mapping.txt')
     self.matching_js_files   = Tempfile.new('test-folder/matching_js_files.txt')
     self.matching_tests      = Tempfile.new('test-folder/matching_tests.txt')
@@ -22,10 +26,15 @@ RSpec.describe Tooling::PredictiveTests, feature_category: :tooling do
     # See https://ruby-doc.org/stdlib-1.9.3/libdoc/tempfile/rdoc/
     #     Tempfile.html#class-Tempfile-label-Explicit+close
     begin
-      example.run
-    ensure
+      # In practice, we let PredictiveTests create the file, and we just
+      # use its file name.
       changed_files.close
       changed_files.unlink
+
+      example.run
+    ensure
+      # Since example.run can create the file again, let's remove it again
+      FileUtils.rm_f(changed_files_path)
       fixtures_mapping.close
       fixtures_mapping.unlink
       matching_js_files.close
@@ -39,7 +48,7 @@ RSpec.describe Tooling::PredictiveTests, feature_category: :tooling do
 
   before do
     stub_env(
-      'RSPEC_CHANGED_FILES_PATH' => changed_files.path,
+      'RSPEC_CHANGED_FILES_PATH' => changed_files_path,
       'RSPEC_MATCHING_TESTS_PATH' => matching_tests.path,
       'RSPEC_VIEWS_INCLUDING_PARTIALS_PATH' => views_with_partials.path,
       'FRONTEND_FIXTURES_MAPPING_PATH' => fixtures_mapping.path,
@@ -50,7 +59,9 @@ RSpec.describe Tooling::PredictiveTests, feature_category: :tooling do
 
     # We write some data to later on verify that we only append to this file.
     File.write(matching_tests.path, matching_tests_initial_content)
-    File.write(fixtures_mapping.path, '{}') # We write valid JSON, so that the file can be processed
+    File.write(fixtures_mapping.path, fixtures_mapping_content)
+
+    allow(Gitlab).to receive(:configure)
   end
 
   describe '#execute' do
@@ -73,14 +84,18 @@ RSpec.describe Tooling::PredictiveTests, feature_category: :tooling do
 
     context 'when all ENV variables are provided' do
       before do
-        File.write(changed_files, changed_files_content)
+        change = double('GitLab::Change') # rubocop:disable RSpec/VerifiedDoubles
+        allow(change).to receive_message_chain(:to_h, :values_at)
+          .and_return([changed_files_content, changed_files_content])
+
+        allow(Gitlab).to receive_message_chain(:merge_request_changes, :changes)
+          .and_return([change])
       end
 
       context 'when no files were changed' do
         let(:changed_files_content) { '' }
 
-        it 'does not change any files' do
-          expect { subject }.not_to change { File.read(changed_files.path) }
+        it 'does not change files other than RSPEC_CHANGED_FILES_PATH' do
           expect { subject }.not_to change { File.read(matching_tests.path) }
           expect { subject }.not_to change { File.read(views_with_partials.path) }
           expect { subject }.not_to change { File.read(fixtures_mapping.path) }
@@ -88,17 +103,27 @@ RSpec.describe Tooling::PredictiveTests, feature_category: :tooling do
         end
       end
 
-      context 'when some files were changed' do
-        let(:changed_files_content) { 'tooling/lib/tooling/predictive_tests.rb' }
+      context 'when some files used for frontend fixtures were changed' do
+        let(:changed_files_content) { 'app/models/todo.rb' }
+        let(:changed_files_matching_test) { 'spec/models/todo_spec.rb' }
+        let(:matching_frontend_fixture) { 'tmp/tests/frontend/fixtures-ee/todos/todos.html' }
+        let(:fixtures_mapping_content) do
+          JSON.dump(changed_files_matching_test => [matching_frontend_fixture]) # rubocop:disable Gitlab/Json
+        end
+
+        it 'writes to RSPEC_CHANGED_FILES_PATH with API contents and appends with matching fixtures' do
+          subject
+
+          expect(File.read(changed_files_path)).to eq("#{changed_files_content} #{matching_frontend_fixture}")
+        end
 
         it 'appends the spec file to RSPEC_MATCHING_TESTS_PATH' do
           expect { subject }.to change { File.read(matching_tests.path) }
             .from(matching_tests_initial_content)
-            .to("#{matching_tests_initial_content} spec/tooling/lib/tooling/predictive_tests_spec.rb")
+            .to("#{matching_tests_initial_content} #{changed_files_matching_test}")
         end
 
-        it 'does not change files other than RSPEC_MATCHING_TESTS_PATH' do
-          expect { subject }.not_to change { File.read(changed_files.path) }
+        it 'does not change files other than RSPEC_CHANGED_FILES_PATH nor RSPEC_MATCHING_TESTS_PATH' do
           expect { subject }.not_to change { File.read(views_with_partials.path) }
           expect { subject }.not_to change { File.read(fixtures_mapping.path) }
           expect { subject }.not_to change { File.read(matching_js_files.path) }