![ReDoc](https://fastapi.tiangolo.com/img/index/index-02-redoc-simple.png)

## Build a Docker Image with a Single-File FastAPI { #build-a-docker-image-with-a-single-file-fastapi }

If your FastAPI is a single file, for example, `main.py` without an `./app` directory, your file structure could look like this:

```
.
├── Dockerfile
├── main.py
└── requirements.txt

        testUser.setRoleNames(new String[] {});
        assertFalse(fessUserBean.hasRole("admin"));

        // Test with single role - matching
        testUser.setRoleNames(new String[] { "admin" });
        assertTrue(fessUserBean.hasRole("admin"));

        // Test with single role - not matching
        assertFalse(fessUserBean.hasRole("user"));

        // Test with multiple roles

            assertEquals(1, Integer.bitCount(DcerpcConstants.DCERPC_CONC_MPX), "DCERPC_CONC_MPX should be a single bit");
            assertEquals(1, Integer.bitCount(DcerpcConstants.DCERPC_DID_NOT_EXECUTE), "DCERPC_DID_NOT_EXECUTE should be a single bit");
            assertEquals(1, Integer.bitCount(DcerpcConstants.DCERPC_MAYBE), "DCERPC_MAYBE should be a single bit");

     * @param <E> the element type
     * @param value the single value returned by the iterator
     * @return an {@link Iterable} wrapping a {@link SingleValueIterator}
     */
    public static <E> Iterable<E> iterable(final E value) {
        return () -> new SingleValueIterator<>(value);
    }

    /**
     * Constructs an instance.
     *
     * @param value the single value returned by the iterator
     */

    public void test_insert_noChains() {
        User user = createTestUser("testuser");
        authenticationManager.insert(user);
        // Should not throw exception even with no chains
    }

    // Test insert with single chain
    public void test_insert_singleChain() {
        User user = createTestUser("testuser");
        TestAuthenticationChain chain = new TestAuthenticationChain();
        authenticationManager.addChain(chain);

<div class="termy">

```console
$ pip install sqlmodel
---> 100%
```

</div>

## Create the App with a Single Model { #create-the-app-with-a-single-model }

We'll create the simplest first version of the app with a single **SQLModel** model first.

Later we'll improve it increasing security and versatility with **multiple models** below. 🤓

### Create Models { #create-models }

Some compiler optimizations that would be valid in single-threaded programs are not valid in all Go programs.
In particular, a compiler must not introduce writes that do not exist in the original program,
it must not allow a single read to observe multiple values,
and it must not allow a single write to write multiple values.
</p>

<p>

/**
 * NTLMSSP AV pair representing single host information in NTLM authentication.
 * Contains host-specific data used during the NTLM challenge-response process.
 *
 * @author mbechler
 */
public class AvSingleHost extends AvPair {

    /**
     * Constructs an AvSingleHost from raw byte data
     *
     * @param raw the raw byte data for the single host AV pair
     */

        assertEquals("a\nb\nc", inputsValue);
    }

    public void test_getInputsValue_withSingleInput() {
        // Test with single input
        String[] inputs = { "single" };
        CharMappingItem item = new CharMappingItem(1L, inputs, "output");

        assertEquals("single", item.getInputsValue());
    }

    public void test_getInputsValue_withNullInputs() {

/// info

`Body` also has all the same extra validation and metadata parameters as `Query`,`Path` and others you will see later.

///

## Embed a single body parameter { #embed-a-single-body-parameter }

Let's say you only have a single `item` body parameter from a Pydantic model `Item`.

By default, **FastAPI** will then expect its body directly.