As dependencies will also be called by **FastAPI** (the same as your *path operation functions*), the same rules apply while defining your functions.

You can use `async def` or normal `def`.

And you can declare dependencies with `async def` inside of normal `def` *path operation functions*, or `def` dependencies inside of `async def` *path operation functions*, etc.

It doesn't matter. **FastAPI** will know what to do.

/// note

## pytest.mark.anyio { #pytest-mark-anyio }

If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously.

## HTTPX { #httpx }

Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath.

        queryHelper.addBoostFunction(ScoreFunctionBuilders.weightFactorFunction(2.0f));

        QueryContext context = buildQuery("test");
        // Verify that function score query contains the added boost function
        assertTrue(context.getQueryBuilder().toString().contains("function_score"));
    }

    @Test
    public void test_addBoostFunction_withFilter() {

import static com.google.common.hash.Hashing.sha512;
import static com.google.common.hash.Hashing.sipHash24;

import org.jspecify.annotations.NullUnmarked;

/**
 * An enum that contains all of the known hash functions.
 *
 * @author Kurt Alfred Kluever
 */
@SuppressWarnings("deprecation") // We still need to test our deprecated APIs.
@NullUnmarked
enum HashFunctionEnum {
  ADLER32(adler32()),
  CRC32(crc32()),

### Other utility functions { #other-utility-functions }

Any other utility function that you call directly can be created with normal `def` or `async def` and FastAPI won't affect the way you call it.

This is in contrast to the functions that FastAPI calls for you: *path operation functions* and dependencies.

///

/// tip

If you want to call `async` functions in your tests apart from sending requests to your FastAPI application (e.g. asynchronous database functions), have a look at the [Async Tests](../advanced/async-tests.md) in the advanced tutorial.

///

## Separating tests { #separating-tests }

## ty

If ty is available, use it to check types.

## Asyncer

When needing to run blocking code inside of async functions, or async code inside of blocking functions, suggest using Asyncer.

Prefer it over AnyIO or asyncio.

Install:

```bash
uv add asyncer
```

Run blocking sync code inside of async with `asyncify()`:

```python

    Map<String, String> map =
        transformValues(ImmutableMap.<String, Integer>of(), Functions.toStringFunction());
    assertMapsEqual(new HashMap<>(), map);
  }

  public void testTransformSingletonMapEquality() {
    Map<String, String> map =
        transformValues(ImmutableMap.of("a", 1), Functions.toStringFunction());
    Map<String, String> expected = ImmutableMap.of("a", "1");
    assertMapsEqual(expected, map);

    Function<? super Integer, Boolean> h = Functions.constant(Boolean.TRUE);
    Function<? super String, Integer> g = new HashCodeFunction();
    Function<Float, String> f = Functions.forMap(m, "F");

    Function<Float, Boolean> c1 = Functions.compose(Functions.compose(h, g), f);
    Function<Float, Boolean> c2 = Functions.compose(h, Functions.compose(g, f));

  }

  @Override
  protected Map<String, String> makePopulatedMap() {
    Map<String, Integer> underlying = new HashMap<>();
    underlying.put("a", 1);
    underlying.put("b", 2);
    underlying.put("c", 3);
    return transformValues(
        new UnmodifiableIteratorMap<String, Integer>(underlying), Functions.toStringFunction());
  }

  @Override