echoRequest.writeBytesWireFormat(buffer, startIndex);

            // Check bytes before written area are unchanged
            for (int i = 0; i < startIndex; i++) {
                assertEquals((byte) 0xFF, buffer[i]);
            }

            // Check bytes after written area are unchanged
            for (int i = startIndex + 4; i < buffer.length; i++) {
                assertEquals((byte) 0xFF, buffer[i]);

{* ../../docs_src/app_testing/tutorial001.py hl[2,12,15:18] *}

/// tip

Notice that the testing functions are normal `def`, not `async def`.

And the calls to the client are also normal calls, not using `await`.

This allows you to use `pytest` directly without complications.

///

/// note | Technical Details

   * OkHttp in the current runtime. Use this to include the OkHttp version in custom `User-Agent`
   * headers.
   *
   * Official OkHttp releases follow [semantic versioning][semver]. Versions with the `-SNAPSHOT`
   * qualifier are not unique and should only be used in development environments. If you create
   * custom builds of OkHttp please include a qualifier your version name, like "4.7.0-mycompany.3".

# user properties at the very beginning of Maven's boot process.
#

# Comma-separated list of files to include.
# Each item may be enclosed in quotes to gracefully include spaces. Items are trimmed before being loaded.
# If the first character of an item is a question mark, the load will silently fail if the file does not exist.
${includes} = ?"${maven.user.conf}/maven-user.properties", \

          ascending: true
          exempt-all-milestones: true

          # ISSUES (deactivated) ----------------------------------------------
          # This workflow should touch no issues, so times are set to -1
          # (see actions/stale documentation for the behavior)
          days-before-issue-stale: -1
          stale-issue-label: stale
          stale-issue-message: >

     * If null, all available web configurations will be crawled (when no other config IDs are specified).
     */
    protected String[] webConfigIds;

    /**
     * Array of file system crawling configuration IDs to process.
     * If null, all available file configurations will be crawled (when no other config IDs are specified).
     */
    protected String[] fileConfigIds;

    /**

    }

    // Test that all expected headers are set
    public void test_allCorsHeadersAreSet() {
        String testOrigin = "https://example.com";
        HttpServletRequest request = createMockRequest();
        HttpServletResponse response = createMockResponse();

        corsHandler.process(testOrigin, request, response);

        // Check all CORS headers are present

          <description>
            The permissions for files when they are created.
          </description>
          <type>String</type>
        </field>
        <field>
          <name>directoryPermissions</name>
          <version>1.0.0+</version>
          <description>
            The permissions for directories when they are created.
          </description>
          <type>String</type>
        </field>

```Python
class Cat:
    def __init__(self, name: str):
        self.name = name


fluffy = Cat(name="Mr Fluffy")
```

In this case, `fluffy` is an instance of the class `Cat`.

And to create `fluffy`, you are "calling" `Cat`.

So, a Python class is also a **callable**.

Then, in **FastAPI**, you could use a Python class as a dependency.

Most of these settings are variable (can change), like database URLs. And many could be sensitive, like secrets.

For this reason it's common to provide them in environment variables that are read by the application.

/// tip