There are some scenarios where you might want to override a dependency during testing.

You don't want the original dependency to run (nor any of the sub-dependencies it might have).

Instead, you want to provide a different dependency that will be used only during tests (possibly only some specific tests), and will provide a value that can be used where the value of the original dependency was used.

### Use cases: external service

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t08-a</artifactId>
        <version>1.0</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t08-b</artifactId>
        <version>1.1</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>

  </scm>
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t05-b</artifactId>
        <version>1.0</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t05-d</artifactId>
        <version>1.0</version>
      </dependency>
    </dependencies>
  </dependencyManagement>
  <dependencies>

    <dependencies>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t07-b</artifactId>
        <version>1.0</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t07-d</artifactId>
        <version>1.0</version>
        <scope>test</scope>
        <optional>false</optional>
      </dependency>
    </dependencies>

  <description>Maven 4 API - Maven SPI.</description>

  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-meta</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-model</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-core</artifactId>

And that way we are able to "parameterize" our dependency, that now has `"bar"` inside of it, as the attribute `checker.fixed_content`.

## Use the instance as a dependency

Then, we could use this `checker` in a `Depends(checker)`, instead of `Depends(FixedContentQueryChecker)`, because the dependency is the instance, `checker`, not the class itself.

And when solving the dependency, **FastAPI** will call this `checker` like:

```Python

    * Required scopes `["items"]` with the dependency:
    * `get_current_active_user`:
        *  The dependency function `get_current_active_user` has:
            * Required scopes `["me"]` with the dependency:
            * `get_current_user`:
                * The dependency function `get_current_user` has:
                    * No scopes required by itself.
                    * A dependency using `oauth2_scheme`.

  <artifactId>t05-b</artifactId>
  <packaging>jar</packaging>
  <version>2.0</version>
  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t05-c</artifactId>
      <version>1.0</version>
      <type>jar</type>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t05-d</artifactId>
      <version>1.1</version>

  <artifactId>t08-b</artifactId>
  <packaging>jar</packaging>
  <version>1.0</version>
  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t08-c</artifactId>
      <version>1.0</version>
      <type>jar</type>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t08-d</artifactId>
      <version>1.1</version>

    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-toolchain-model</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-builder-support</artifactId>
    </dependency>
    <dependency>
      <groupId>org.codehaus.plexus</groupId>
      <artifactId>plexus-interpolation</artifactId>
    </dependency>
    <dependency>