1 files changed, 238 insertions, 0 deletions
diff --git a/spec/lib/gitlab/diff/position_tracer/image_strategy_spec.rb b/spec/lib/gitlab/diff/position_tracer/image_strategy_spec.rb
new file mode 100644
index 00000000000..900816af53a
--- /dev/null
+++ b/spec/lib/gitlab/diff/position_tracer/image_strategy_spec.rb
@@ -0,0 +1,238 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Diff::PositionTracer::ImageStrategy do
+  include PositionTracerHelpers
+
+  let(:project) { create(:project, :repository) }
+  let(:current_user) { project.owner }
+  let(:file_name) { 'test-file' }
+  let(:new_file_name) { "#{file_name}-new" }
+  let(:second_file_name) { "#{file_name}-2" }
+  let(:branch_name) { 'position-tracer-test' }
+  let(:old_position) { position(old_path: file_name, new_path: file_name, position_type: 'image') }
+
+  let(:tracer) do
+    Gitlab::Diff::PositionTracer.new(
+      project: project,
+      old_diff_refs: old_diff_refs,
+      new_diff_refs: new_diff_refs
+    )
+  end
+
+  let(:strategy) { described_class.new(tracer) }
+
+  subject { strategy.trace(old_position) }
+
+  let(:initial_commit) do
+    project.commit(create_branch(branch_name, 'master')[:branch].name)
+  end
+
+  describe '#trace' do
+    describe 'diff scenarios' do
+      let(:create_file_commit) do
+        initial_commit
+
+        create_file(
+          branch_name,
+          file_name,
+          Base64.encode64('content')
+        )
+      end
+
+      let(:update_file_commit) do
+        create_file_commit
+
+        update_file(
+          branch_name,
+          file_name,
+          Base64.encode64('updatedcontent')
+        )
+      end
+
+      let(:update_file_again_commit) do
+        update_file_commit
+
+        update_file(
+          branch_name,
+          file_name,
+          Base64.encode64('updatedcontentagain')
+        )
+      end
+
+      let(:delete_file_commit) do
+        create_file_commit
+        delete_file(branch_name, file_name)
+      end
+
+      let(:rename_file_commit) do
+        delete_file_commit
+
+        create_file(
+          branch_name,
+          new_file_name,
+          Base64.encode64('renamedcontent')
+        )
+      end
+
+      let(:create_second_file_commit) do
+        create_file_commit
+
+        create_file(
+          branch_name,
+          second_file_name,
+          Base64.encode64('morecontent')
+        )
+      end
+
+      let(:create_another_file_commit) do
+        create_file(
+          branch_name,
+          second_file_name,
+          Base64.encode64('morecontent')
+        )
+      end
+
+      let(:update_another_file_commit) do
+        update_file(
+          branch_name,
+          second_file_name,
+          Base64.encode64('updatedmorecontent')
+        )
+      end
+
+      context 'when the file was created in the old diff' do
+        context 'when the file is unchanged between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(initial_commit, create_file_commit) }
+          let(:new_diff_refs) { diff_refs(initial_commit, create_second_file_commit) }
+
+          it 'returns the new position' do
+            expect_new_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file was updated between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(initial_commit, create_file_commit) }
+          let(:new_diff_refs) { diff_refs(initial_commit, update_file_commit) }
+          let(:change_diff_refs) { diff_refs(create_file_commit, update_file_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file was renamed in between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(initial_commit, create_file_commit) }
+          let(:new_diff_refs) { diff_refs(initial_commit, rename_file_commit) }
+          let(:change_diff_refs) { diff_refs(create_file_commit, rename_file_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file was removed in between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(initial_commit, create_file_commit) }
+          let(:new_diff_refs) { diff_refs(initial_commit, delete_file_commit) }
+          let(:change_diff_refs) { diff_refs(create_file_commit, delete_file_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file is unchanged in the new diff' do
+          let(:old_diff_refs) { diff_refs(initial_commit, create_file_commit) }
+          let(:new_diff_refs) { diff_refs(create_another_file_commit, update_another_file_commit) }
+          let(:change_diff_refs) { diff_refs(initial_commit, create_another_file_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+      end
+
+      context 'when the file was changed in the old diff' do
+        context 'when the file is unchanged in between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(create_file_commit, update_file_commit) }
+          let(:new_diff_refs) { diff_refs(create_file_commit, create_second_file_commit) }
+
+          it 'returns the new position' do
+            expect_new_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file was updated in between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(create_file_commit, update_file_commit) }
+          let(:new_diff_refs) { diff_refs(create_file_commit, update_file_again_commit) }
+          let(:change_diff_refs) { diff_refs(update_file_commit, update_file_again_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file was renamed in between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(create_file_commit, update_file_commit) }
+          let(:new_diff_refs) { diff_refs(create_file_commit, rename_file_commit) }
+          let(:change_diff_refs) { diff_refs(update_file_commit, rename_file_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file was removed in between the old and the new diff' do
+          let(:old_diff_refs) { diff_refs(create_file_commit, update_file_commit) }
+          let(:new_diff_refs) { diff_refs(create_file_commit, delete_file_commit) }
+          let(:change_diff_refs) { diff_refs(update_file_commit, delete_file_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+
+        context 'when the file is unchanged in the new diff' do
+          let(:old_diff_refs) { diff_refs(create_file_commit, update_file_commit) }
+          let(:new_diff_refs) { diff_refs(create_another_file_commit, update_another_file_commit) }
+          let(:change_diff_refs) { diff_refs(create_file_commit, create_another_file_commit) }
+
+          it 'returns the position of the change' do
+            expect_change_position(
+              old_path: file_name,
+              new_path: file_name
+            )
+          end
+        end
+      end
+    end
+  end
+end