Например, так: `pip install httpx`.

///

Импортируйте `TestClient`.

Создайте объект `TestClient`, передав ему в качестве параметра Ваше приложение **FastAPI**.

Создайте функцию, название которой должно начинаться с `test_` (это стандарт из соглашений `pytest`).

Используйте объект `TestClient` так же, как Вы используете `httpx`.

Напишите простое утверждение с `assert` дабы проверить истинность Python-выражения (это тоже стандарт `pytest`).

**FastAPI** 提供了和 `starlette.testclient` 一样的 `fastapi.testclient`，只是为了方便开发者。但它直接来自Starlette。

///

/// tip | "提示"

除了发送请求之外，如果你还想测试时在FastAPI应用中调用 `async` 函数（例如异步数据库函数）， 可以在高级教程中看下 [Async Tests](../advanced/async-tests.md){.internal-link target=_blank} 。

///

## 分离测试

在实际应用中，你可能会把你的测试放在另一个文件里。

您的**FastAPI**应用程序也可能由一些文件/模块组成等等。

### **FastAPI** app 文件

def test_post_files(tmp_path):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")
    path2 = tmp_path / "test2.txt"
    path2.write_bytes(b"<file content2>")

    client = TestClient(app)
    with path.open("rb") as file, path2.open("rb") as file2:
        response = client.post(
            "/files/",
            files=(
                ("files", ("test.txt", file)),
                ("files", ("test2.txt", file2)),

                it.name != "distributions-integ-tests" && // distributions:integTest is part of Build Distributions
                it.name != "soak" // soak tests have their own test category
        }

        assertFalse(projectFoldersWithFunctionalTests.isEmpty())
        projectFoldersWithFunctionalTests.forEach {
            assertTrue(projectDirsWithFunctionalTests.contains(it), "Contains functional tests: $it")
        }
    }

...
BUILD SUCCESSFUL in 1m 30s
63 actionable tasks: 61 executed, 2 up-to-date

```

    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")
    path2 = tmp_path / "test2.txt"
    path2.write_bytes(b"<file content2>")

    client = TestClient(app)
    with path.open("rb") as file, path2.open("rb") as file2:
        response = client.post(
            "/files/",
            files=(
                ("files", ("test.txt", file)),
                ("files", ("test2.txt", file2)),

            "failed-report-with-leftover/build/tmp/teŝt files",
            "successful-report/build/tmp/teŝt files",
            "failed-test-with-leftover/build/tmp/teŝt files"
        )
    }

    @Test
    fun `build does not fail if a flaky test has leftover files`() {
        val result = run(":flaky-test-with-leftover:test", "--no-watch-fs").build()

import com.google.common.collect.Ordering;
import java.util.Comparator;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for ordering the elements of graphs. */
@RunWith(JUnit4.class)
public final class ElementOrderTest {
  // Node order tests

  @Test
  public void nodeOrder_none() {

   * </ul>
   *
   * <p>In all cases, if {@code C} needs custom logic for testing nulls, you can add an explicit
   * {@code testNulls()} test in the corresponding {@code CTest} class, and {@code C} will be
   * excluded from the automated null tests performed by this method.
   */
  @Test
  public void testNulls() throws Exception {
    for (Class<?> classToTest : findClassesToTest(loadClassesInPackage(), NULL_TEST_METHOD_NAMES)) {

    return FluentIterable.from(ImmutableList.<Number>of());
  }

  /*
   * The following tests demonstrate the shortcomings of or() and test that the casting workaround
   * mentioned in the method Javadoc does in fact compile.
   */

  @SuppressWarnings("unused") // compilation test
  public void testSampleCodeError1() {
    Optional<Integer> optionalInt = getSomeOptionalInt();