# Async Tests { #async-tests }

You have already seen how to test your **FastAPI** applications using the provided `TestClient`. Up to now, you have only seen how to write synchronous tests, without using `async` functions.

        when(fileHandle.acquire()).thenReturn(fileHandle);
        when(fileHandle.getTree()).thenReturn(tree);

        // Mock response and send behavior
        Smb2IoctlResponse resp = mock(Smb2IoctlResponse.class);
        when(resp.getOutputLength()).thenReturn(42);
        when(tree.send(any(Smb2IoctlRequest.class), any())).thenReturn(resp);

        byte[] out = new byte[10];

   */
  // Define
  TF_Operation* feed = Placeholder(func_graph_, s_);
  Define(-1, {}, {feed}, {feed}, {});

  // Use, run, and verify
  TF_Operation* func_feed = Placeholder(host_graph_, s_);
  TF_Operation* func_op = Use({func_feed});
  Run({{func_feed, Int32Tensor(3)}}, func_op, 3);
  VerifyFDef(empty_, {{"feed_0", DT_INT32}}, {{"feed", DT_INT32}},
             {{"feed_0", "feed"}}, {});
}

===========

This document describes the concurrency considerations for http/2 connections and the connection pool within OkHttp.

## HTTP/2 Connections

The HttpURLConnection API is a blocking API. You make a blocking write to send a request, and a blocking read to receive the response.

#### Blocking APIs

		return fmt.Errorf("Expected MinIO binary checksum: %s, seen: %s", s1.Checksum, s2.Checksum)
	}

	ns1 := s1.NEndpoints
	ns2 := s2.NEndpoints
	if ns1 != ns2 {
		return fmt.Errorf("Expected number of endpoints %d, seen %d", ns1, ns2)
	}

	for i, cmdLine := range s1.CmdLines {
		if cmdLine != s2.CmdLines[i] {
			return fmt.Errorf("Expected command line argument %s, seen %s", cmdLine,
				s2.CmdLines[i])
		}
	}

        int newNext = getNext(entry, mask);
        if (lastEntryIndex == -1) {
          // we need to update the root link from table[]
          tableSet(table, tableIndex, newNext);
        } else {
          // we need to update the link from the chain
          entries[lastEntryIndex] = maskCombine(entries[lastEntryIndex], newNext, mask);
        }

/// tip

This is a somewhat advanced technique, and in most of the cases you won't really need it, as you can raise exceptions (including `HTTPException`) from inside of the rest of your application code, for example, in the *path operation function*.

But it's there for you if you need it. 🤓

///

{* ../../docs_src/dependencies/tutorial008b_an_py39.py hl[18:22,31] *}

* `write(data)`: Записує `data` (`str` або `bytes`) у файл.
* `read(size)`: Читає `size` (`int`) байтів/символів з файлу.
* `seek(offset)`: Переміщується до позиції `offset` (`int`) у файлі.
    * Наприклад, `await myfile.seek(0)` поверне курсор на початок файлу.

  * If you are an individual writing original source code and you're sure you own the intellectual property, then you'll need to sign an [individual CLA](https://code.google.com/legal/individual-cla-v1.0.html).
  * If you work for a company that wants to allow you to contribute your work, then you'll need to sign a [corporate CLA](https://code.google.com/legal/corporate-cla-v1.0.html).

        int newNext = getNext(entry, mask);
        if (lastEntryIndex == -1) {
          // we need to update the root link from table[]
          tableSet(table, tableIndex, newNext);
        } else {
          // we need to update the link from the chain
          entries[lastEntryIndex] = maskCombine(entries[lastEntryIndex], newNext, mask);
        }