# Testing { #testing }

Thanks to <a href="https://www.starlette.io/testclient/" class="external-link" target="_blank">Starlette</a>, testing **FastAPI** applications is easy and enjoyable.

It is based on <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, which in turn is designed based on Requests, so it's very familiar and intuitive.

# Testing Dependencies with Overrides { #testing-dependencies-with-overrides }

## Overriding dependencies during testing { #overriding-dependencies-during-testing }

There are some scenarios where you might want to override a dependency during testing.

You don't want the original dependency to run (nor any of the sub-dependencies it might have).

# Testing WebSockets { #testing-websockets }

You can use the same `TestClient` to test WebSockets.

For this, you use the `TestClient` in a `with` statement, connecting to the WebSocket:

{* ../../docs_src/app_testing/tutorial002.py hl[27:31] *}

/// note

For more details, check Starlette's documentation for <a href="https://www.starlette.io/testclient/#testing-websocket-sessions" class="external-link" target="_blank">testing WebSockets</a>.

# Testing a Database { #testing-a-database }

You can study about databases, SQL, and SQLModel in the <a href="https://sqlmodel.tiangolo.com/" class="external-link" target="_blank">SQLModel docs</a>. 🤓

There's a mini <a href="https://sqlmodel.tiangolo.com/tutorial/fastapi/" class="external-link" target="_blank">tutorial on using SQLModel with FastAPI</a>. ✨

# Testing Events: lifespan and startup - shutdown { #testing-events-lifespan-and-startup-shutdown }

When you need `lifespan` to run in your tests, you can use the `TestClient` with a `with` statement:

{* ../../docs_src/app_testing/tutorial004.py hl[9:15,18,27:28,30:32,41:43] *}


You can read more details about the ["Running lifespan in tests in the official Starlette documentation site."](https://www.starlette.io/lifespan/#running-lifespan-in-tests)

 * limitations under the License.
 */

package com.google.common.collect.testing;

import static com.google.common.collect.testing.testers.ListListIteratorTester.getListIteratorFullyModifiableMethod;
import static com.google.common.collect.testing.testers.ListSubListTester.getSubListOriginalListSetAffectsSubListLargeListMethod;
import static com.google.common.collect.testing.testers.ListSubListTester.getSubListOriginalListSetAffectsSubListMethod;

    private MultiChannelManager multiChannelManager;
    private Configuration config;

    @BeforeEach
    void setUp() throws Exception {
        // Create a basic configuration for testing
        this.config = new BaseConfiguration(true);
        this.multiChannelManager = new MultiChannelManager(config);
    }

    @Test
    @DisplayName("MultiChannelManager should initialize successfully")

		{Name: uuid.NewString(), Age: 21},
		{Name: uuid.NewString(), Age: 22},
		{Name: uuid.NewString(), Age: 23},
	}

	if err := gorm.G[User](DB).CreateInBatches(ctx, &users, 2); err != nil {
		t.Fatalf("CreateInBatches failed: %v", err)
	}

	userIds := []uuid.UUID{}
	if err := gorm.G[User](DB).Select("name").Where("id in ?", []uint{users[0].ID, users[1].ID, users[2].ID}).Order("age").Scan(ctx, &userIds); err != nil || len(users) != 3 {

- **Memory efficient** - Specialized collections like `LruHashMap` and `ArrayMap` for memory-conscious applications
- **Java 21 features** - Switch expressions and pattern matching for reduced overhead

## 🧪 Building and Testing

### Development Setup
```bash
# Clone the repository
git clone https://github.com/codelibs/corelib.git
cd corelib

# Compile the project
mvn clean compile

# Run all tests
mvn test

    - advanced/sub-applications.md
    - advanced/behind-a-proxy.md
    - advanced/templates.md
    - advanced/websockets.md
    - advanced/events.md
    - advanced/testing-websockets.md
    - advanced/testing-events.md
    - advanced/testing-dependencies.md
    - advanced/async-tests.md
    - advanced/settings.md
    - advanced/openapi-callbacks.md
    - advanced/openapi-webhooks.md
    - advanced/wsgi.md