```console
$ pip install httpx
```

///

Import `TestClient`.

Create a `TestClient` by passing your **FastAPI** application to it.

Create functions with a name that starts with `test_` (this is standard `pytest` conventions).

Use the `TestClient` object the same way as you do with `httpx`.

        return new LinkMetaData(methodMetaData.style, displayName, urlFragment);
    }

    private MethodLinkMetaData findMethod(String method) {
        if (method.endsWith("...)")) {
            // Should reuse the link parsing stuff from JavadocLinkConverter instead
            method = method.substring(0, method.length() - 4) + "[])";
        }

        MethodLinkMetaData metaData = methods.get(method);
        if (metaData != null) {

        <artifactId>animal-sniffer-maven-plugin</artifactId>
      </plugin>
      <plugin>
        <artifactId>maven-javadoc-plugin</artifactId>
        <configuration>
          <!-- Passing `-subpackages com.google.common` breaks things, so we explicitly exclude everything else instead. -->
          <!-- excludePackageNames requires specification of packages separately from "all subpackages".

package lifecycle

import (
	"encoding/xml"
	"fmt"
	"testing"

	"github.com/dustin/go-humanize"
)

// TestUnsupportedFilters checks if parsing Filter xml with
// unsupported elements returns appropriate errors
func TestUnsupportedFilters(t *testing.T) {
	testCases := []struct {
		inputXML    string
		expectedErr error
	}{
		{ // Filter with And tags

* <abbr title="also known as: serialization, parsing, marshalling">Conversion</abbr> of input data: coming from the network to Python data and types. Reading from:
    * JSON.
    * Path parameters.
    * Query parameters.
    * Cookies.
    * Headers.
    * Forms.
    * Files.

		message:    "Encountered an invalid record type.",
		statusCode: 400,
		cause:      err,
	}
}

// ////////////////////////////////////////////////////////////////////////////////////
//
//	SQL parsing errors.
//
// ////////////////////////////////////////////////////////////////////////////////////
func errLexerInvalidChar(err error) *s3Error {
	return &s3Error{
		code:       "LexerInvalidChar",

The `str | None` (Python 3.10+) or `Union` in `Union[str, None]` (Python 3.9+) is not used by FastAPI to determine that the value is not required, it will know it's not required because it has a default value of `= None`.

But adding the type annotations will allow your editor to give you better support and detect errors.

///

## Without Pydantic { #without-pydantic }

import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * CompactLinkedHashSet is an implementation of a Set, which a predictable iteration order that
 * matches the insertion order. All optional operations (adding and removing) are supported. All
 * elements, including {@code null}, are permitted.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)

import java.util.Spliterators;
import org.jspecify.annotations.Nullable;

/**
 * CompactLinkedHashSet is an implementation of a Set, which a predictable iteration order that
 * matches the insertion order. All optional operations (adding and removing) are supported. All
 * elements, including {@code null}, are permitted.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)

   */
  @CanIgnoreReturnValue
  public static UnsignedLong valueOf(String string, int radix) {
    return fromLongBits(UnsignedLongs.parseUnsignedLong(string, radix));
  }

  /**
   * Returns the result of adding this and {@code val}. If the result would have more than 64 bits,
   * returns the low 64 bits of the result.
   *
   * @since 14.0
   */
  public UnsignedLong plus(UnsignedLong val) {