def spec1 = Stub(Spec)
        def spec2 = Stub(Spec)

        expect:
        def intersect1 = Specs.intersect(spec1, spec2)
        intersect1 instanceof AndSpec
        intersect1.specs == [spec1, spec2]

        def intersect2 = Specs.intersect([spec1, spec2])
        intersect2 instanceof AndSpec
        intersect2.specs == [spec1, spec2]
    }

    def "intersection of nothing and other specs is nothing"() {

            @Override
            public void visitFileTree(File root, PatternSet patterns, FileTreeInternal fileTree) {
                PatternSet intersect = patterns.intersect();
                intersect.copyFrom(FilteredMinimalFileTree.this.patterns);
                visitor.visitFileTree(root, intersect, owner);
            }

            @Override

        range.intersect(GeneralRange.range(ORDERING, 1, OPEN, 3, OPEN)));
  }

  public void testIntersectNonOverlappingRange() {
    GeneralRange<Integer> range = GeneralRange.range(ORDERING, 2, OPEN, 4, CLOSED);
    assertTrue(range.intersect(GeneralRange.range(ORDERING, 5, CLOSED, 6, CLOSED)).isEmpty());
    assertTrue(range.intersect(GeneralRange.range(ORDERING, 1, OPEN, 2, OPEN)).isEmpty());
  }

        !patternSet.intersect().isEmpty()

        when:
        patternSet = new PatternSet()
        patternSet.exclude { false }
        then:
        !patternSet.isEmpty()
        !patternSet.intersect().isEmpty()

        when:
        patternSet = new PatternSet()
        patternSet.exclude("*.txt")
        then:
        !patternSet.isEmpty()
        !patternSet.intersect().isEmpty()
    }

	return append(xl, yl...).norm()
}

// intersect returns the intersection xl ∩ yl.
func (xl termlist) intersect(yl termlist) termlist {
	if xl.isEmpty() || yl.isEmpty() {
		return nil
	}

	// Quadratic algorithm, but good enough for now.
	// TODO(gri) fix asymptotic performance
	var rl termlist
	for _, x := range xl {
		for _, y := range yl {
			if r := x.intersect(y); r != nil {
				rl = append(rl, r)
			}

// "intersect" subcommands of "go tool covdata".

import (
	"flag"
	"fmt"
	"internal/coverage"
	"internal/coverage/decodecounter"
	"internal/coverage/decodemeta"
	"internal/coverage/pods"
	"os"
	"strings"
)

// makeSubtractIntersectOp creates a subtract or intersect operation.
// 'mode' here must be either "subtract" or "intersect".

		x := testTerm(args[0])
		y := testTerm(args[1])
		want := testTerm(args[2])
		if got := x.intersect(y); !got.equal(want) {
			t.Errorf("%v.intersect(%v) = %v; want %v", x, y, got, want)
		}
		// intersect is symmetric
		x, y = y, x
		if got := x.intersect(y); !got.equal(want) {
			t.Errorf("%v.intersect(%v) = %v; want %v", x, y, got, want)
		}
	}
}

func TestTermIncludes(t *testing.T) {

	return append(xl, yl...).norm()
}

// intersect returns the intersection xl ∩ yl.
func (xl termlist) intersect(yl termlist) termlist {
	if xl.isEmpty() || yl.isEmpty() {
		return nil
	}

	// Quadratic algorithm, but good enough for now.
	// TODO(gri) fix asymptotic performance
	var rl termlist
	for _, x := range xl {
		for _, y := range yl {
			if r := x.intersect(y); r != nil {
				rl = append(rl, r)
			}

        @Override
        public final StrictVersionConstraints union(StrictVersionConstraints other) {
            return other;
        }

        @Override
        public final StrictVersionConstraints intersect(StrictVersionConstraints other) {
            return EMPTY;
        }

        @Override
        public boolean isEmpty() {
            return true;
        }

        @Override

	$

6. Subtract one profile from another

	$ go tool covdata subtract -i=indir1,indir2 -o=outdir
	$

7. Intersect profiles

	$ go tool covdata intersect -i=indir1,indir2 -o=outdir
	$

8. Dump a profile for debugging purposes.

	$ go tool covdata debugdump -i=indir
	<human readable output>
	$
*/