docs: translated demo/tests into ja

Author: Msksgm

content/ja/docs/demo/tests.md

@@ -0,0 +1,26 @@
+---
+title: Tests
+default_lang_commit: 7cb1bd39726fc03698164ee17fe9087afdac054c
+cSpell:ignore: Tracetest
+---
+
+Currently, the repository includes E2E tests for both the frontend and backend
+services. For the Frontend we are using [Cypress](https://www.cypress.io/)
+execute the different flows in the web store. While the backend services use
+[AVA](https://avajs.dev) as the main testing framework for integration tests and
+[Tracetest](https://tracetest.io/) for trace-based tests.
+
+To run all the tests, execute `make run-tests` from the root directory.
+
+Otherwise, if you want to run a specific suite of tests you can execute specific
+commands for each type of test[^1]:
+
+- **Frontend tests**: `docker compose run frontendTests`
+- **Backend tests**:
+  - Integration: `docker compose run integrationTests`
+  - Trace-based: `docker compose run traceBasedTests`
+
+To learn more about these tests, see
+[Service Testing](https://github.com/open-telemetry/opentelemetry-demo/tree/main/test).
+
+[^1]: {{% param notes.docker-compose-v2 %}}