private final LittleEndianDataOutputStream out = new LittleEndianDataOutputStream(baos);

  public void testWriteLittleEndian() throws IOException {

    /* Write out various test values in LITTLE ENDIAN FORMAT */
    out.write(new byte[] {-100, 100});
    out.writeBoolean(true);
    out.writeBoolean(false);
    out.writeByte(100);
    out.writeByte(-100);
    out.writeByte((byte) 200);
    out.writeChar('a');

  private final LittleEndianDataOutputStream out = new LittleEndianDataOutputStream(baos);

  public void testWriteLittleEndian() throws IOException {

    /* Write out various test values in LITTLE ENDIAN FORMAT */
    out.write(new byte[] {-100, 100});
    out.writeBoolean(true);
    out.writeBoolean(false);
    out.writeByte(100);
    out.writeByte(-100);
    out.writeByte((byte) 200);
    out.writeChar('a');

  }

  public void testReadLittleEndian() throws IOException {
    DataInput in = new LittleEndianDataInputStream(new ByteArrayInputStream(data));

    /* Read in various values in LITTLE ENDIAN FORMAT */
    byte[] b = new byte[2];
    in.readFully(b);
    assertEquals(-100, b[0]);
    assertEquals(100, b[1]);
    assertEquals(true, in.readBoolean());
    assertEquals(false, in.readBoolean());

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

/// check | Authorize button!

You already have a shiny new "Authorize" button.

And your *path operation* has a little lock in the top-right corner that you can click.

///

And if you click it, you have a little authorization form to type a `username` and `password` (and other optional fields):

<img src="/img/tutorial/security/image02.png">

/// note

}

[data-termynal]:before {
    content: '';
    position: absolute;
    top: 15px;
    left: 15px;
    display: inline-block;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    /* A little hack to display the window buttons in one pseudo element. */
    background: #d9515d;
    -webkit-box-shadow: 25px 0 0 #f4c025, 50px 0 0 #3ec930;
            box-shadow: 25px 0 0 #f4c025, 50px 0 0 #3ec930;
}

   * compatible pure-Java fallback.
   */
  private static final LittleEndianBytes byteArray = makeGetter();

  /**
   * Load 8 bytes into long in a little endian manner, from the substring between position and
   * position + 8. The array must have at least 8 bytes from offset (inclusive).
   *
   * @param input the input bytes

Some time ago, [a **FastAPI** user asked](https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920):

> What’s the history of this project? It seems to have come from nowhere to awesome in a few weeks [...]

Here's a little bit of that history.

## Alternatives { #alternatives }

```

</div>

It is **HIGHLY encouraged** that you write or copy the code, edit it and run it locally.

Using it in your editor is what really shows you the benefits of FastAPI, seeing how little code you have to write, all the type checks, autocompletion, etc.

---

## Install FastAPI { #install-fastapi }

The first step is to install FastAPI.

* dependable: dependable (do not translate to "confiable" or "fiable")
* list (as in Python list): list
* context manager: context manager (do not translate to "gestor de contexto" or "administrador de contexto")
* a little bit: un poquito
* graph (data structure, as in "dependency graph"): grafo (do not translate to "gráfico")
* form data: form data (do not translate to "datos de formulario" or "datos de form")

Here's where it becomes important to be able to declare <abbr title="greater than"><code>gt</code></abbr> and not just <abbr title="greater than or equal"><code>ge</code></abbr>. As with it you can require, for example, that a value must be greater than `0`, even if it is less than `1`.

So, `0.5` would be a valid value. But `0.0` or `0` would not.

And the same for <abbr title="less than"><code>lt</code></abbr>.