maven-core-it file:///${basedir}/repo true true . pom.xml src/** src/main/resources src/main/java/org/apache/maven/its/mng3906/SomeClass.java src/main/java/org/apache/maven/its/mng3906/SomeClass.java package org.apache.maven.its.mng3906; public class SomeClass { } META-INF/maven/org.apache.maven.its.mng3906/c/pom.xml 4.0.0 org.apache.maven.its.mng3906 c 0.1 jar maven-core-it file:///${basedir}/repo true true . pom.xml src/** src/main/resources META-INF/maven/org.apache.maven.its.mng3906/c/pom.properties...

///

## The main `FastAPI` { #the-main-fastapi }

Now, let's see the module at `app/main.py`.

Here's where you import and use the class `FastAPI`.

This will be the main file in your application that ties everything together.

And as most of your logic will now live in its own specific module, the main file will be quite simple.

### Import `FastAPI` { #import-fastapi }

And if you update that local FastAPI source code when you run that Python file again, it will use the fresh version of FastAPI you just edited.

That way, you don't have to "install" your local version to be able to test every change.

/// note | Technical Details

{* ../../docs_src/python_types/tutorial004_py39.py hl[2] *}

## Declaring types { #declaring-types }

You just saw the main place to declare type hints. As function parameters.

This is also the main place you would use them with **FastAPI**.

### Simple types { #simple-types }

You can declare all the standard Python types, not only `str`.

You can use, for example:

cd dbflute_fess
./manage.sh    # On Linux/Mac
manage.bat     # On Windows
# Select option 23 (generate)
```

This will regenerate:
- `src/main/java/org/codelibs/fess/mylasta/action/FessLabels.java`
- `src/main/java/org/codelibs/fess/mylasta/action/FessMessages.java`
- `src/main/java/org/codelibs/fess/mylasta/direction/FessProp.java`

### 5. Rebuild the Project

```bash
mvn clean package
```

.
├── app
│   ├── __init__.py
│   └── main.py
```

在 `main.py` 文件中你有一个 **FastAPI** app:


{* ../../docs_src/app_testing/main.py *}

### 测试文件

然后你会有一个包含测试的文件 `test_main.py` 。app可以像Python包那样存在（一样是目录，但有个 `__init__.py` 文件）：

``` hl_lines="5"
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

因为这文件在同一个包中，所以你可以通过相对导入从 `main` 模块（`main.py`）导入`app`对象：

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

En el archivo `main.py` tienes tu aplicación de **FastAPI**:

{* ../../docs_src/app_testing/app_a_py39/main.py *}

### Archivo de prueba { #testing-file }

     */
    public void test_stackTraceWithCause() {
        Exception cause = new IllegalArgumentException("Cause exception");
        CrawlerSystemException exception = new CrawlerSystemException("Main exception", cause);

        StackTraceElement[] mainStackTrace = exception.getStackTrace();
        StackTraceElement[] causeStackTrace = cause.getStackTrace();

        assertNotNull(mainStackTrace);

And then they can try again knowing that it's probably something more similar to `stanleyjobsox` than to `johndoe`.

#### A "professional" attack { #a-professional-attack }

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

In der Datei `main.py` haben Sie Ihre **FastAPI**-Anwendung:


{* ../../docs_src/app_testing/app_a_py39/main.py *}


### Testdatei { #testing-file }