<dependencies>

    <dependency>
      <groupId>maven-test-runtime</groupId>
      <artifactId>scope-default</artifactId>
      <version>1.0</version>
    </dependency>

    <dependency>
      <groupId>maven-test-runtime</groupId>
      <artifactId>scope-test</artifactId>
      <version>1.0</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>maven-test-runtime</groupId>

/**
 * Tests {@code Dependency}.
 *
 */
class DependencyTest {

    @Test
    void testHashCodeNullSafe() {
        new Dependency().hashCode();
    }

    @Test
    void testEqualsNullSafe() {
        assertFalse(new Dependency().equals(null));

        new Dependency().equals(new Dependency());
    }

    @Test
    void testEqualsIdentity() {

* subclass
* child class
* sibling class
* class method

* header
* headers
* authorization header
* `Authorization` header
* forwarded header

* dependency injection system
* dependency
* dependable
* dependant

* I/O bound
* CPU bound
* concurrency
* parallelism
* multiprocessing

* env var
* environment variable
* `PATH`
* `PATH` variable

    }

    @Override
    public Artifact createDependencyArtifact(Dependency dependency) {
        Artifact artifact = new DefaultArtifact(
                dependency.getGroupId(),
                dependency.getArtifactId(),
                dependency.getVersion(),
                dependency.getScope(),
                dependency.getType(),
                dependency.getClassifier(),

        return resolve(
                DependencyResolverRequest.build(session, DependencyResolverRequest.RequestType.RESOLVE, dependency));
    }

    @Nonnull
    default DependencyResolverResult resolve(
            @Nonnull Session session, @Nonnull DependencyCoordinates dependency, @Nonnull PathScope scope) {

    <dependencies>

      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t10-a</artifactId>
        <version>1.0</version>
        <scope>test</scope>
      </dependency>

      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t10-b</artifactId>
        <version>1.0</version>
        <scope>runtime</scope>
      </dependency>

      <dependency>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t05-a</artifactId>
        <version>1.0</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t05-b</artifactId>
        <version>1.1</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t07-a</artifactId>
        <version>1.0</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t07-b</artifactId>
        <version>1.1</version>
      </dependency>
      <dependency>
        <groupId>maven-test</groupId>

We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

A "**callable**" in Python is anything that Python can "call" like a function.

            Map<String, Dependency> dependencies = new LinkedHashMap<>();

            DependencyManagement depMgmt = target.getDependencyManagement();

            if (depMgmt != null) {
                for (Dependency dependency : depMgmt.getDependencies()) {
                    dependencies.put(dependency.getManagementKey(), dependency);
                }
            } else {