public void testCustomEscaper_withpercent() {
    UnicodeEscaper e = new PercentEscaper("%", false);
    assertEquals("foo%7Cbar", e.escape("foo|bar"));
    assertEquals("foo%7Cbar", e.escape("foo%7Cbar")); // idempotent
  }

  /** Test that giving a null 'safeChars' string causes a {@link NullPointerException}. */
  public void testBadArguments_null() {

    assert response.json() == {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}


def test_query_params_str_validations_item_query_fixedquery(client: TestClient):
    response = client.get("/items/", params={"item-query": "fixedquery"})
    assert response.status_code == 200
    assert response.json() == {
        "items": [{"item_id": "Foo"}, {"item_id": "Bar"}],
        "q": "fixedquery",
    }

    assert response.json() == {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}


@needs_py310
def test_query_params_str_validations_item_query_fixedquery(client: TestClient):
    response = client.get("/items/", params={"item-query": "fixedquery"})
    assert response.status_code == 200
    assert response.json() == {
        "items": [{"item_id": "Foo"}, {"item_id": "Bar"}],
        "q": "fixedquery",
    }

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:

from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI(swagger_ui_oauth2_redirect_url=None)


@app.get("/items/")
async def read_items():
    return {"id": "foo"}


client = TestClient(app)


def test_swagger_ui():
    response = client.get("/docs")
    assert response.status_code == 200, response.text
    assert response.headers["content-type"] == "text/html; charset=utf-8"

# Test required and embedded body parameters with no bodies sent
@needs_py39
def test_post_body_example(client: TestClient):
    response = client.put(
        "/items/5",
        json={
            "name": "Foo",
            "description": "A very nice Item",
            "price": 35.4,
            "tax": 3.2,
        },
    )
    assert response.status_code == 200


@needs_py39

# Test required and embedded body parameters with no bodies sent
@needs_py310
def test_post_body_example(client: TestClient):
    response = client.put(
        "/items/5",
        json={
            "name": "Foo",
            "description": "A very nice Item",
            "price": 35.4,
            "tax": 3.2,
        },
    )
    assert response.status_code == 200


@needs_py310

class Item(BaseModel):
    name: Union[str, None] = None
    description: Union[str, None] = None
    price: Union[float, None] = None
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},
    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}

  @GwtIncompatible // StringBuilder.append in GWT invokes Object.toString(), unlike the JRE version.
  public void testDontConvertCharSequenceToString() {
    assertEquals("foo,foo", Joiner.on(",").join(new DontStringMeBro(), new DontStringMeBro()));
    assertEquals(
        "foo,bar,foo",
        Joiner.on(",").useForNull("bar").join(new DontStringMeBro(), null, new DontStringMeBro()));
  }

  @J2ktIncompatible

	b.ReportAllocs()

	b.RunParallel(func(pb *testing.PB) {
		foo := 0
		for pb.Next() {
			rwm := NewDRWMutex(ds, "test")
			foo++
			if foo%writeRatio == 0 {
				rwm.Lock(id, source)
				rwm.Unlock(context.Background())
			} else {
				rwm.RLock(id, source)
				for i := 0; i != localWork; i++ {
					foo *= 2
					foo /= 2
				}
				rwm.RUnlock(context.Background())
			}
		}
		_ = foo