Use project.commit convenience method.

spec/lib/gitlab/diff/file_spec.rb

spec/lib/gitlab/diff/parser_spec.rb

...lib/gitlab/markdown/commit_range_reference_filter_spec.rb

spec/lib/gitlab/markdown/commit_reference_filter_spec.rb

spec/lib/gitlab/reference_extractor_spec.rb

spec/mailers/notify_spec.rb

spec/models/commit_spec.rb

spec/models/note_spec.rb

spec/services/git_push_service_spec.rb

spec/services/git_tag_push_service_spec.rb