Fix issue #8145: Add docs about runtime tests (#8146)

tests/runtime/README.md

@@ -0,0 +1,60 @@
+## Runtime Tests
+
+This folder contains integration tests that verify the functionality of OpenHands' runtime environments and their interactions with various tools and features.
+
+### What are Runtime Tests?
+
+Runtime tests focus on testing:
+- Tool interactions within a runtime environment (bash commands, browsing, file operations)
+- Environment setup and configuration
+- Resource management and cleanup
+- Browser-based operations and file viewing capabilities
+- IPython/Jupyter integration
+- Environment variables and configuration handling
+
+The tests can be run against different runtime environments (Docker, Local, Remote, Runloop, or Daytona) by setting the TEST_RUNTIME environment variable. By default, tests run using the Docker runtime.
+
+### How are they different from Unit Tests?
+
+While unit tests in `tests/unit/` focus on testing individual components in isolation, runtime tests verify:
+1. Integration between components
+2. Actual execution of commands in different runtime environments
+3. System-level interactions (file system, network, browser)
+4. Environment setup and teardown
+5. Tool functionality in real runtime contexts
+
+### Running the Tests
+
+Run all runtime tests:
+
+```bash
+poetry run pytest ./tests/runtime
+```
+
+Run specific test file:
+
+```bash
+poetry run pytest ./tests/runtime/test_bash.py
+```
+
+Run specific test:
+
+```bash
+poetry run pytest ./tests/runtime/test_bash.py::test_bash_command_env
+```
+
+For verbose output, add the `-v` flag (more verbose: `-vv` and `-vvv`):
+
+```bash
+poetry run pytest -v ./tests/runtime/test_bash.py
+```
+
+### Environment Variables
+
+The runtime tests can be configured using environment variables:
+- `TEST_IN_CI`: Set to 'True' when running in CI environment
+- `TEST_RUNTIME`: Specify the runtime to test ('docker', 'local', 'remote', 'runloop', 'daytona')
+- `RUN_AS_OPENHANDS`: Set to 'True' to run tests as openhands user (default), 'False' for root
+- `SANDBOX_BASE_CONTAINER_IMAGE`: Specify a custom base container image for Docker runtime
+
+For more details on pytest usage, see the [pytest documentation](https://docs.pytest.org/en/latest/contents.html).