client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        ("/items/", 200, [{"name": "Foo", "price": 42}]),
        ("/users/", 200, [{"username": "johndoe"}]),
        ("/elements/", 200, [{"item_id": "Foo"}]),
    ],
)
def test_query_params_str_validations(path, expected_status, expected_response):
    response = client.get(path)

  public void testNullIsPassedThrough() {
    Converter<String, String> nullsArePassed = sillyConverter(false);
    assertEquals("forward", nullsArePassed.convert("foo"));
    assertEquals("forward", nullsArePassed.convert(null));
    assertEquals("backward", nullsArePassed.reverse().convert("foo"));
    assertEquals("backward", nullsArePassed.reverse().convert(null));
  }

  public void testNullIsNotPassedThrough() {

client = TestClient(app)


def test_default_query_values():
    url = "/items/"
    response = client.get(url)
    assert response.status_code == 200, response.text
    assert response.json() == {"q": ["foo", "bar"]}


def test_multi_query_values():
    url = "/items/?q=baz&q=foobar"
    response = client.get(url)
    assert response.status_code == 200, response.text
    assert response.json() == {"q": ["baz", "foobar"]}

from docs_src.query_params_str_validations.tutorial013_an import app

client = TestClient(app)


def test_multi_query_values():
    url = "/items/?q=foo&q=bar"
    response = client.get(url)
    assert response.status_code == 200, response.text
    assert response.json() == {"q": ["foo", "bar"]}


def test_query_no_values():
    url = "/items/"
    response = client.get(url)
    assert response.status_code == 200, response.text

    suite.addTestSuite(CharSourceTest.class);
    return suite;
  }

  private static final String STRING = ASCII + I18N;
  private static final String LINES = "foo\nbar\r\nbaz\rsomething";
  private static final ImmutableList<String> SPLIT_LINES =
      ImmutableList.of("foo", "bar", "baz", "something");

  private TestCharSource source;

  @Override
  public void setUp() {
    source = new TestCharSource(STRING);
  }

```Python hl_lines="6-7"
{!../../docs_src/path_params/tutorial001.py!}
```

这段代码把路径参数 `item_id` 的值传递给路径函数的参数 `item_id`。

运行示例并访问 <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>，可获得如下响应：

```JSON
{"item_id":"foo"}
```

## 声明路径参数的类型

使用 Python 标准类型注解，声明路径操作函数中路径参数的类型。

```Python hl_lines="7"
{!../../docs_src/path_params/tutorial002.py!}
```

    assertFailsWith<SSLPeerUnverifiedException> {
      certificatePinner.check("foo.example.co.uk", listOf(certB1.certificate))
    }
    assertFailsWith<SSLPeerUnverifiedException> {
      certificatePinner.check("foo.bar.example.co.uk", listOf(certB1.certificate))
    }
    assertFailsWith<SSLPeerUnverifiedException> {
      certificatePinner.check("foo.bar.baz.example.co.uk", listOf(certB1.certificate))
    }

KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <build>
    <resources>
      <resource>

      </resource>
    </resources>
    <testResources>
      <testResource>

KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <reporting>
    <plugins>
      <plugin>

      </plugin>
    </plugins>
  </reporting>

So, if you run this example and go to <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, you will see a response of:

```JSON
{"item_id":"foo"}
```

## Path parameters with types

You can declare the type of a path parameter in the function, using standard Python type annotations: