then:
        1 * dependency.visitDependencies(_) >> { TaskDependencyResolveContext context ->
            context.add(otherDependency)
            context.add(otherDependency2)
        }
        1 * otherDependency.visitDependencies(_) >> { TaskDependencyResolveContext context -> context.add(otherDependency2) }
        1 * otherDependency2.visitDependencies(_) >> { TaskDependencyResolveContext context -> context.add(target) }

            @Override
            void visitDependencies(TaskDependencyResolveContext context) {
                context.add(dependencySource)
            }
        }

        given:
        1 * dependencySource.visitDependencies(_) >> { TaskDependencyResolveContext context -> context.add(dependency1) }
        1 * dependencySource.visitDependencies(_) >> { TaskDependencyResolveContext context -> context.add(dependency2) }

            @Override
            void visitDependencies(TaskDependencyResolveContext context) {
                context.add(dependencySource)
            }
        }

        given:
        1 * dependencySource.visitDependencies(_) >> { TaskDependencyResolveContext context -> context.add(dependency1) }
        1 * dependencySource.visitDependencies(_) >> { TaskDependencyResolveContext context -> context.add(dependency2) }

        when:
        DefaultRealizableTaskCollection collection = new DefaultRealizableTaskCollection(Class, Stub(TaskCollection), registry.node(path), instantiator)
        collection.visitDependencies(Stub(TaskDependencyResolveContext))
        collection.visitDependencies(Stub(TaskDependencyResolveContext))

        then:
        noExceptionThrown()
    }
}

class BasicTask extends DefaultTask {}

class ChildTask extends BasicTask {}

                super(buildOperationRunner);
            }

            @Override
            public void visitDependencies(TaskDependencyResolveContext context) {
                super.visitDependencies(context);
                context.add(artifact);
            }

            @Override

        PatternFilterable patterns = getPatterns();
        tree.visitContentsAsFileTrees(child -> visitor.accept(child.matching(patterns)));
    }

    @Override
    public void visitDependencies(TaskDependencyResolveContext context) {
        tree.visitDependencies(context);
    }

    }

    @Override
    public DefaultTaskDependency visitingDependencies(Consumer<? super TaskDependencyResolveContext> visitDependencies) {
        return configurableDependency(ImmutableSet.of(new DefaultTaskDependency.VisitBehavior(visitDependencies)));
    }

        TestFileSet fileSet = Mock()
        FileCollectionAdapter adapter = new FileCollectionAdapter(fileSet)
        TaskDependencyResolveContext context = Mock()

        when:
        adapter.visitDependencies(context)

        then:
        1 * context.add(fileSet)
    }

    def visitDependenciesDoesNotDelegateToTargetCollectionWhenItDoesNotImplementBuildable() {
        MinimalFileSet fileSet = Mock()

        return right;
    }

    @Override
    public String getDisplayName() {
        return "file collection";
    }

    @Override
    public void visitDependencies(TaskDependencyResolveContext context) {
        left.visitDependencies(context);
    }

    @Override
    protected Set<File> getIntrinsicFiles() {
        Set<File> files = new LinkedHashSet<File>(left.getFiles());

        for (ResolvedArtifactSet set : sets) {
            set.visitExternalArtifacts(visitor);
        }
    }

    @Override
    public void visitDependencies(TaskDependencyResolveContext context) {
        for (ResolvedArtifactSet set : sets) {
            set.visitDependencies(context);
        }
    }