{!../../../docs_src/async_tests/test_main.py!}
```

## Run it

You can run your tests as usual via:

<div class="termy">

```console
$ pytest

---> 100%
```

</div>

## In Detail

The marker `@pytest.mark.anyio` tells pytest that this test function should be called asynchronously:

```Python hl_lines="7"
{!../../../docs_src/async_tests/test_main.py!}
```

!!! tip

        while (!source.exhausted()) {
          var rule: ByteString = source.readUtf8LineStrict().toRule() ?: continue

          if (rule.startsWith(EXCEPTION_RULE_MARKER)) {
            rule = rule.substring(1)
            // We use '\n' for end of value.
            totalExceptionRuleBytes += rule.size + 1
            sortedExceptionRules.add(rule)
          } else {

    /**
     * Creates a new event source and immediately returns it. Creating an event source initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must cancel the returned event source when it is no longer in use.
     */
    fun newEventSource(
      request: Request,
      listener: EventSourceListener,
    ): EventSource
  }

     either this License or such Secondary License(s).

3.4. Notices

     You may not remove or alter the substance of any license notices (including
     copyright notices, patent notices, disclaimers of warranty, or limitations
     of liability) contained within the Source Code Form of the Covered
     Software, except that You may alter any license notices to the extent
     required to remedy known factual inaccuracies.

            token,
        )
    }
    add(FirErrors.OPT_IN_ARGUMENT_IS_NOT_MARKER) { firDiagnostic ->
        OptInArgumentIsNotMarkerImpl(
            firDiagnostic.a,
            firDiagnostic as KtPsiDiagnostic,
            token,
        )
    }
    add(FirErrors.OPT_IN_MARKER_WITH_WRONG_TARGET) { firDiagnostic ->
        OptInMarkerWithWrongTargetImpl(
            firDiagnostic.a,

      a) it must be made available under this Agreement; and

b) a copy of this Agreement must be included with each copy of the Program.

Contributors may not remove or alter any copyright notices contained within
the Program.

Each Contributor must identify itself as the originator of its Contribution,
if any, in a manner that reasonably allows subsequent Recipients to identify

  override fun request(): Request = originalRequest

  /**
   * Immediately closes the socket connection if it's currently held. Use this to interrupt an
   * in-flight request from any thread. It's the caller's responsibility to close the request body
   * and response body streams; otherwise resources may be leaked.
   *
   * This method is safe to be called concurrently, but provides limited guarantees. If a transport

  // These properties are guarded by [lock].

  /**
   * If true, no new exchanges can be created on this connection. It is necessary to set this to
   * true when removing a connection from the pool; otherwise a racing caller might get it from the
   * pool when it shouldn't. Symmetrically, this must always be checked before returning a
   * connection from the pool.
   *
   * Once true this is always true. Guarded by this.
   */

 *
 * Implementations authenticate by returning a follow-up request that includes an authorization
 * header, or they may decline the challenge by returning null. In this case the unauthenticated
 * response will be returned to the caller that triggered it.
 *
 * Implementations should check if the initial request already included an attempt to
 * authenticate. If so it is likely that further attempts will not be useful and the authenticator
 * should give up.

You can use the same dependency overrides from [Testing Dependencies with Overrides](testing-dependencies.md){.internal-link target=_blank} to alter a database for testing.

You could want to set up a different database for testing, rollback the data after the tests, pre-fill it with some testing data, etc.

The main idea is exactly the same you saw in that previous chapter.