leftoverFiles.forEach {
            assertTrue(projectDir.resolve(it).walk().filter { it.isFile }.toList().isEmpty())
        }
    }

    @Test
    fun `fail build if leftover file found and test passes`() {
        val result = run(":successful-test-with-leftover:test", "--no-watch-fs").buildAndFail()
        assertEquals(TaskOutcome.SUCCESS, result.task(":successful-test-with-leftover:test")!!.outcome)

---

**Note**: You can mix `def` and `async def` in your *path operation functions* as much as you need and define each one using the best option for you. FastAPI will do the right thing with them.

Anyway, in any of the cases above, FastAPI will still work asynchronously and be extremely fast.

But by following the steps above, it will be able to do some performance optimizations.

## Technical Details

      long d = (n - 1) >> r;
      base %= n;
      if (base == 0) {
        return true;
      }
      // Calculate a := base^d mod n.
      long a = powMod(base, d, n);
      // n passes this test if
      //    base^d = 1 (mod n)
      // or base^(2^j * d) = -1 (mod n) for some 0 <= j < r.
      if (a == 1) {
        return true;
      }
      int j = 0;
      while (a != n - 1) {

   * opening the data stream.
   *
   * <p>The default implementation returns {@link Optional#absent}. Some sources, such as a {@code
   * CharSequence}, may return a non-absent value. Note that in such cases, it is <i>possible</i>
   * that this method will return a different number of chars than would be returned by reading all
   * of the chars.
   *

<img src="/img/tutorial/dataclasses/image01.png">

## Dataclasses in Nested Data Structures

You can also combine `dataclasses` with other type annotations to make nested data structures.

In some cases, you might still have to use Pydantic's version of `dataclasses`. For example, if you have errors with the automatically generated API documentation.

    // may change and break assumptions in this test [*]. This is not a bug in the implementation of
    // Ascii.equalsIgnoreCase(), but it is a signal that its documentation may need updating as
    // regards edge cases.

    // The Unicode point {@code 00df} is the lowercase form of sharp-S (ß), whose uppercase is "SS".
    assertEquals("PASSWORD", "pa\u00dfword".toUpperCase()); // [*]

        }
      }
    } finally {
      cancelInFlightConnects()
    }

    throw firstException!!
  }

  /**
   * Returns non-null if we don't need to wait for the launched result. In such cases, this result
   * must be processed before whatever is waiting in the queue because we may have already acquired
   * its connection.
   */
  private fun launchTcpConnect(): ConnectResult? {
    val plan =

import com.google.common.annotations.GwtCompatible;
import java.util.Map;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Test cases for a {@link Table} implementation supporting reads and writes.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

  }

  /*
   * AbstractCollection fails the removeAll(null) test when the subject
   * collection is empty, but we'd still like to test removeAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRemoveAll_nullCollectionReferenceEmptySubject() {

### Tags with Enums

If you have a big application, you might end up accumulating **several tags**, and you would want to make sure you always use the **same tag** for related *path operations*.

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

```Python hl_lines="1  8-10  13  18"
{!../../docs_src/path_operation_configuration/tutorial002b.py!}
```