def setup() {
        NativeServicesTestFixture.initialize()
    }

    def canAddFileTree() {
        FileTreeInternal set1 = Mock(FileTreeInternal)
        when:
        set.addToUnion(set1)

        then:
        set.sourceCollections == [set1]
    }

    def cannotAddFileCollection() {
        when:

    FileTreeInternal treeOf(MinimalFileTree tree);

    static FileTreeInternal emptyTree() {
        return EmptyFileTree.INSTANCE;
    }

    static FileTreeInternal emptyTree(String displayName) {
        if (FileTreeInternal.DEFAULT_TREE_DISPLAY_NAME.equals(displayName)) {
            return emptyTree();
        } else {
            return new EmptyFileTree(displayName);
        }
    }

import java.util.function.Supplier;

public class FilteredFileTree extends CompositeFileTree implements FileCollectionInternal.Source {
    private final FileTreeInternal tree;
    private final Supplier<? extends PatternSet> patternSupplier;

    public FilteredFileTree(FileTreeInternal tree, TaskDependencyFactory taskDependencyFactory, Factory<PatternSet> patternSetFactory, Supplier<? extends PatternSet> patternSupplier) {

        return this;
    }

    @Override
    public FileTreeInternal matching(PatternFilterable patterns) {
        return this;
    }

    @Override
    public FileTree visit(FileVisitor visitor) {
        return this;
    }

    @Override
    public void visitContentsAsFileTrees(Consumer<FileTreeInternal> visitor) {
    }

    @Override

        public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
            fileSystemAccess.read(
                root.getAbsolutePath(),
                new PatternSetSnapshottingFilter(patterns, stat)
            )
                .map(roots::add);
        }

        @Override
        public void visitFileTreeBackedByFile(File file, FileTreeInternal fileTree, FileSystemMirroringFileTree sourceTree) {

    public void visitContentsAsFileTrees(Consumer<FileTreeInternal> visitor) {
        visitor.accept(this);
    }

    @Override
    protected void visitContents(FileCollectionStructureVisitor visitor) {
        tree.visitStructure(new MinimalFileTree.MinimalFileTreeStructureVisitor() {

            @Override
            public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {

 * limitations under the License.
 */

package org.gradle.api.internal.file.collections

import org.gradle.api.file.FileVisitDetails
import org.gradle.api.file.FileVisitor
import org.gradle.api.internal.file.FileTreeInternal
import org.gradle.api.specs.Spec
import org.gradle.api.tasks.util.PatternSet
import org.gradle.util.UsesNativeServices
import spock.lang.Specification

@UsesNativeServices

 */

package org.gradle.plugins.ide.eclipse.model.internal;

import org.gradle.api.NonNullApi;
import org.gradle.api.Project;
import org.gradle.api.Task;
import org.gradle.api.internal.file.FileTreeInternal;
import org.gradle.api.internal.tasks.JvmConstants;
import org.gradle.api.internal.tasks.compile.CompilationSourceDirs;
import org.gradle.api.tasks.compile.JavaCompile;
import org.gradle.internal.jvm.JavaModuleDetector;

package org.gradle.tooling.internal.provider.continuous;

import org.gradle.api.internal.file.FileCollectionInternal;
import org.gradle.api.internal.file.FileCollectionStructureVisitor;
import org.gradle.api.internal.file.FileTreeInternal;
import org.gradle.api.internal.file.collections.FileSystemMirroringFileTree;
import org.gradle.api.tasks.util.PatternSet;
import org.gradle.internal.execution.UnitOfWork;

                @Override
                public void visitFileTreeBackedByFile(File file, FileTreeInternal fileTree, FileSystemMirroringFileTree sourceTree) {
                    failOnInvalidOutputType(fileTree);
                }

                @Override
                public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {