def a1 = file("a/1.txt") << "a/1"
        def b1 = file("b/1.txt") << "b/1"
        def fileResolver = TestFiles.fileCollectionFactory(testDirectory)

        when:
        def a = fileResolver.resolving(["a"]).asFileTree
        def b = fileResolver.resolving(["b"]).asFileTree
        def composite = newCompositeFileTree([a, b])

        then:
        composite.files == [a1, b1].toSet()
    }

    def "can visit all files"() {

	b0, err0 := io.ReadAll(golden)
	b1, err1 := io.ReadAll(lzwr)
	if err0 != nil {
		t.Errorf("%s (order=%d litWidth=%d): %v", fn, order, litWidth, err0)
		return
	}
	if err1 != nil {
		t.Errorf("%s (order=%d litWidth=%d): %v", fn, order, litWidth, err1)
		return
	}
	if len(b1) != len(b0) {
		t.Errorf("%s (order=%d litWidth=%d): length mismatch %d != %d", fn, order, litWidth, len(b1), len(b0))
		return
	}

replace (
	a v0.1.0 => ./a1
	b v0.1.0 => ./b1
	c v0.1.0 => ./c1
	c v0.2.0 => ./c2
)
-- a1/go.mod --
module a

go 1.17

require b v0.1.0
-- a1/a.go --
package a
-- a1/a_test.go --
package a_test

import _ "b/x"
-- b1/go.mod --
module b

go 1.17

require c v0.1.0
-- b1/x/x.go --
package x
-- b1/y/y.go --
package y

import "c"

		for len(b0.Succs) == 1 && len(b0.Preds) == 1 {
			pb0, b0 = b0, b0.Preds[0].b
		}
		if b0.Kind != BlockIf {
			continue
		}
		pb1, b1 := b, b.Preds[1].b
		for len(b1.Succs) == 1 && len(b1.Preds) == 1 {
			pb1, b1 = b1, b1.Preds[0].b
		}
		if b1 != b0 {
			continue
		}
		// b0 is the if block giving the boolean value.
		// reverse is the predecessor from which the truth value comes.
		var reverse int

        createDirs("buildB", "buildB/buildSrc", "buildB/buildSrc/b1", "buildB/buildSrc/b2")
        buildB.file("buildSrc/settings.gradle") << """
            $settings
            include 'b1', 'b2'
        """
        buildB.file("buildSrc/build.gradle") << """
            allprojects { apply plugin: 'java' }
            dependencies { implementation project(':b1') }
            project(':b1') { dependencies { implementation project(':b2') } }

type T[P any] struct {
	_ P
}

type S /* ERROR "invalid recursive type" */ struct {
	_ T[S]
}

// simplified test 1

var _ A1[A1[string]]

type A1[P any] struct {
	_ B1[P]
}

type B1[P any] struct {
	_ P
}

// simplified test 2
var _ B2[A2]

type A2 struct {
	_ B2[string]
}

type B2[P any] struct {
	_ C2[P]
}

type C2[P any] struct {
	_ P
}

// license that can be found in the LICENSE file.

package ssa

import (
	"cmd/compile/internal/types"
	"strings"
	"testing"
)

func TestSCCPBasic(t *testing.T) {
	c := testConfig(t)
	fun := c.Fun("b1",
		Bloc("b1",
			Valu("mem", OpInitMem, types.TypeMem, 0, nil),
			Valu("v1", OpConst64, c.config.Types.Int64, 20, nil),
			Valu("v2", OpConst64, c.config.Types.Int64, 21, nil),

		fm.AddUnit("lit.go", "f3", true, u, 0)
	}

	var b1, b2, b3, b4 strings.Builder
	if err := fm.EmitTextual(&b1); err != nil {
		t.Fatalf("EmitTextual returned %v", err)
	}
	wantText := strings.TrimSpace(`
mode: atomic
p.go:10.0,11.0 2 0
p.go:15.0,11.0 1 1
q.go:20.0,25.0 3 0
q.go:30.0,31.0 2 1
q.go:33.0,40.0 7 2
lit.go:99.0,100.0 1 0`)
	gotText := strings.TrimSpace(b1.String())
	if wantText != gotText {

# if needed to process newly-reolved imports.

env TESTGO_VERSION=go1.21.0
env TESTGO_VERSION_SWITCH=switch

cp go.mod go.mod.orig

# tidy reports needing 1.22.0 for b1
env GOTOOLCHAIN=local
! go mod tidy
stderr '^go: example imports\n\texample.net/b: module ./b1 requires go >= 1.22.0 \(running go 1.21.0; GOTOOLCHAIN=local\)$'
env GOTOOLCHAIN=auto
go mod tidy

cmp stderr tidy-stderr.want
cmp go.mod go.mod.tidy

// on it (perhaps due to a missed file in a VCS commit).
-- a1/a.go --
package a
import _ "example.net/b"

-- b1/go.mod --
module example.net/b

go 1.15
-- b1/b.go --
package b

-- b2/go.mod --
module example.net/b

go 1.15

require example.net/c v0.1.0
-- b2/b.go --
package b

-- c1/go.mod --
module example.net/c