cmd/go: convert final module tests to scripts

Change-Id: Iba68b3aaf4a132bd4ca44edf4912a46549d2ef8f
Reviewed-on: https://go-review.googlesource.com/124700Reviewed-by: Bryan C. Mills <bcmills@google.com>

src/cmd/go/proxy_test.go

@@ -231,6 +231,8 @@ func findHash(m module.Version) string {
 
 var archiveCache par.Cache
 
+var cmdGoDir, _ = os.Getwd()
+
 func readArchive(path, vers string) *txtar.Archive {
 	enc, err := module.EncodePath(path)
 	if err != nil {

src/cmd/go/script_test.go

@@ -294,20 +294,37 @@ Script:
 // NOTE: If you make changes here, update testdata/script/README too!
 //
 var scriptCmds = map[string]func(*testScript, bool, []string){
-	"cd":     (*testScript).cmdCd,
-	"cp":     (*testScript).cmdCp,
-	"env":    (*testScript).cmdEnv,
-	"exec":   (*testScript).cmdExec,
-	"exists": (*testScript).cmdExists,
-	"go":     (*testScript).cmdGo,
-	"grep":   (*testScript).cmdGrep,
-	"mkdir":  (*testScript).cmdMkdir,
-	"rm":     (*testScript).cmdRm,
-	"skip":   (*testScript).cmdSkip,
-	"stale":  (*testScript).cmdStale,
-	"stderr": (*testScript).cmdStderr,
-	"stdout": (*testScript).cmdStdout,
-	"stop":   (*testScript).cmdStop,
+	"addcrlf": (*testScript).cmdAddcrlf,
+	"cd":      (*testScript).cmdCd,
+	"cmp":     (*testScript).cmdCmp,
+	"cp":      (*testScript).cmdCp,
+	"env":     (*testScript).cmdEnv,
+	"exec":    (*testScript).cmdExec,
+	"exists":  (*testScript).cmdExists,
+	"go":      (*testScript).cmdGo,
+	"grep":    (*testScript).cmdGrep,
+	"mkdir":   (*testScript).cmdMkdir,
+	"rm":      (*testScript).cmdRm,
+	"skip":    (*testScript).cmdSkip,
+	"stale":   (*testScript).cmdStale,
+	"stderr":  (*testScript).cmdStderr,
+	"stdout":  (*testScript).cmdStdout,
+	"stop":    (*testScript).cmdStop,
+	"symlink": (*testScript).cmdSymlink,
+}
+
+// addcrlf adds CRLF line endings to the named files.
+func (ts *testScript) cmdAddcrlf(neg bool, args []string) {
+	if len(args) == 0 {
+		ts.fatalf("usage: addcrlf file...")
+	}
+
+	for _, file := range args {
+		file = ts.mkabs(file)
+		data, err := ioutil.ReadFile(file)
+		ts.check(err)
+		ts.check(ioutil.WriteFile(file, bytes.Replace(data, []byte("\n"), []byte("\r\n"), -1), 0666))
+	}
 }
 
 // cd changes to a different directory.
@@ -335,6 +352,40 @@ func (ts *testScript) cmdCd(neg bool, args []string) {
 	fmt.Fprintf(&ts.log, "%s\n", ts.cd)
 }
 
+// cmp compares two files.
+func (ts *testScript) cmdCmp(neg bool, args []string) {
+	if neg {
+		// It would be strange to say "this file can have any content except this precise byte sequence".
+		ts.fatalf("unsupported: ! cmp")
+	}
+	if len(args) != 2 {
+		ts.fatalf("usage: cmp file1 file2")
+	}
+
+	name1, name2 := args[0], args[1]
+	var text1, text2 string
+	if name1 == "stdout" {
+		text1 = ts.stdout
+	} else if name1 == "stderr" {
+		text1 = ts.stderr
+	} else {
+		data, err := ioutil.ReadFile(ts.mkabs(name1))
+		ts.check(err)
+		text1 = string(data)
+	}
+
+	data, err := ioutil.ReadFile(ts.mkabs(name2))
+	ts.check(err)
+	text2 = string(data)
+
+	if text1 == text2 {
+		return
+	}
+
+	fmt.Fprintf(&ts.log, "[diff -%s +%s]\n%s\n", name1, name2, diff(text1, text2))
+	ts.fatalf("%s and %s differ", name1, name2)
+}
+
 // cp copies files, maybe eventually directories.
 func (ts *testScript) cmdCp(neg bool, args []string) {
 	if neg {
@@ -516,22 +567,6 @@ func (ts *testScript) cmdStale(neg bool, args []string) {
 	}
 }
 
-// stop stops execution of the test (marking it passed).
-func (ts *testScript) cmdStop(neg bool, args []string) {
-	if neg {
-		ts.fatalf("unsupported: ! stop")
-	}
-	if len(args) > 1 {
-		ts.fatalf("usage: stop [msg]")
-	}
-	if len(args) == 1 {
-		fmt.Fprintf(&ts.log, "stop: %s\n", args[0])
-	} else {
-		fmt.Fprintf(&ts.log, "stop\n")
-	}
-	ts.stopped = true
-}
-
 // stdout checks that the last go command standard output matches a regexp.
 func (ts *testScript) cmdStdout(neg bool, args []string) {
 	scriptMatch(ts, neg, args, ts.stdout, "stdout")
@@ -614,6 +649,35 @@ func scriptMatch(ts *testScript, neg bool, args []string, text, name string) {
 	}
 }
 
+// stop stops execution of the test (marking it passed).
+func (ts *testScript) cmdStop(neg bool, args []string) {
+	if neg {
+		ts.fatalf("unsupported: ! stop")
+	}
+	if len(args) > 1 {
+		ts.fatalf("usage: stop [msg]")
+	}
+	if len(args) == 1 {
+		fmt.Fprintf(&ts.log, "stop: %s\n", args[0])
+	} else {
+		fmt.Fprintf(&ts.log, "stop\n")
+	}
+	ts.stopped = true
+}
+
+// symlink creates a symbolic link.
+func (ts *testScript) cmdSymlink(neg bool, args []string) {
+	if neg {
+		ts.fatalf("unsupported: ! symlink")
+	}
+	if len(args) != 3 || args[1] != "->" {
+		ts.fatalf("usage: symlink file -> target")
+	}
+	// Note that the link target args[2] is not interpreted with mkabs:
+	// it will be interpreted relative to the directory file is in.
+	ts.check(os.Symlink(args[2], ts.mkabs(args[0])))
+}
+
 // Helpers for command implementations.
 
 // abbrev abbreviates the actual work directory in the string s to the literal string "$WORK".
@@ -727,3 +791,104 @@ func (ts *testScript) parse(line string) []string {
 	}
 	return args
 }
+
+// diff returns a formatted diff of the two texts,
+// showing the entire text and the minimum line-level
+// additions and removals to turn text1 into text2.
+// (That is, lines only in text1 appear with a leading -,
+// and lines only in text2 appear with a leading +.)
+func diff(text1, text2 string) string {
+	if text1 != "" && !strings.HasSuffix(text1, "\n") {
+		text1 += "(missing final newline)"
+	}
+	lines1 := strings.Split(text1, "\n")
+	lines1 = lines1[:len(lines1)-1] // remove empty string after final line
+	if text2 != "" && !strings.HasSuffix(text2, "\n") {
+		text2 += "(missing final newline)"
+	}
+	lines2 := strings.Split(text2, "\n")
+	lines2 = lines2[:len(lines2)-1] // remove empty string after final line
+
+	// Naive dynamic programming algorithm for edit distance.
+	// https://en.wikipedia.org/wiki/Wagner–Fischer_algorithm
+	// dist[i][j] = edit distance between lines1[:len(lines1)-i] and lines2[:len(lines2)-j]
+	// (The reversed indices make following the minimum cost path
+	// visit lines in the same order as in the text.)
+	dist := make([][]int, len(lines1)+1)
+	for i := range dist {
+		dist[i] = make([]int, len(lines2)+1)
+		if i == 0 {
+			for j := range dist[0] {
+				dist[0][j] = j
+			}
+			continue
+		}
+		for j := range dist[i] {
+			if j == 0 {
+				dist[i][0] = i
+				continue
+			}
+			cost := dist[i][j-1] + 1
+			if cost > dist[i-1][j]+1 {
+				cost = dist[i-1][j] + 1
+			}
+			if lines1[len(lines1)-i] == lines2[len(lines2)-j] {
+				if cost > dist[i-1][j-1] {
+					cost = dist[i-1][j-1]
+				}
+			}
+			dist[i][j] = cost
+		}
+	}
+
+	var buf strings.Builder
+	i, j := len(lines1), len(lines2)
+	for i > 0 || j > 0 {
+		cost := dist[i][j]
+		if i > 0 && j > 0 && cost == dist[i-1][j-1] && lines1[len(lines1)-i] == lines2[len(lines2)-j] {
+			fmt.Fprintf(&buf, " %s\n", lines1[len(lines1)-i])
+			i--
+			j--
+		} else if i > 0 && cost == dist[i-1][j]+1 {
+			fmt.Fprintf(&buf, "-%s\n", lines1[len(lines1)-i])
+			i--
+		} else {
+			fmt.Fprintf(&buf, "+%s\n", lines2[len(lines2)-j])
+			j--
+		}
+	}
+	return buf.String()
+}
+
+var diffTests = []struct {
+	text1 string
+	text2 string
+	diff  string
+}{
+	{"a b c", "a b d e f", "a b -c +d +e +f"},
+	{"", "a b c", "+a +b +c"},
+	{"a b c", "", "-a -b -c"},
+	{"a b c", "d e f", "-a -b -c +d +e +f"},
+	{"a b c d e f", "a b d e f", "a b -c d e f"},
+	{"a b c e f", "a b c d e f", "a b c +d e f"},
+}
+
+func TestDiff(t *testing.T) {
+	for _, tt := range diffTests {
+		// Turn spaces into \n.
+		text1 := strings.Replace(tt.text1, " ", "\n", -1)
+		if text1 != "" {
+			text1 += "\n"
+		}
+		text2 := strings.Replace(tt.text2, " ", "\n", -1)
+		if text2 != "" {
+			text2 += "\n"
+		}
+		out := diff(text1, text2)
+		// Cut final \n, cut spaces, turn remaining \n into spaces.
+		out = strings.Replace(strings.Replace(strings.TrimSuffix(out, "\n"), " ", "", -1), "\n", " ", -1)
+		if out != tt.diff {
+			t.Errorf("diff(%q, %q) = %q, want %q", text1, text2, out, tt.diff)
+		}
+	}
+}

src/cmd/go/testdata/mod/mod_sync.txt

+env GO111MODULE=on
+
+# sync removes unused y, but everything else is used
+go mod -sync -v
+stderr '^unused y.1'
+! stderr '^unused [^y]'
+
+go list -m all
+! stdout '^y'
+stdout '^w.1 v1.2.0'
+stdout '^z.1 v1.2.0'
+
+-- go.mod --
+module m
+
+require (
+	x.1 v1.0.0
+	y.1 v1.0.0
+	w.1 v1.2.0
+)
+
+replace x.1 v1.0.0 => ../x
+replace y.1 v1.0.0 => ../y
+replace z.1 v1.1.0 => ../z
+replace z.1 v1.2.0 => ../z
+replace w.1 => ../w
+
+-- m.go --
+package m
+
+import _ "x.1"
+import _ "z.1/sub"
+
+-- w/go.mod --
+module w
+
+-- w/w.go --
+package w
+
+-- x/go.mod --
+module x
+require w.1 v1.1.0
+require z.1 v1.1.0
+
+-- x/x.go --
+package x
+import _ "w.1"
+
+-- y/go.mod --
+module y
+require z.1 v1.2.0
+
+-- z/go.mod --
+module z
+
+-- z/sub/sub.go --
+package sub

src/cmd/go/testdata/script/README

@@ -85,6 +85,13 @@ The commands are:
 - cd dir
   Change to the given directory for future commands.
 
+- cmp file1 file2
+  Check that the named files have the same content.
+  By convention, file1 is the actual data and file2 the expected data.
+  File1 can be "stdout" or "stderr" to use the standard output or standard error
+  from the most recent exec or go command.
+  (If the files have differing content, the failure prints a diff.)
+
 - cp src... dst
   Copy the listed files to the target file or existing directory.
 
@@ -133,6 +140,9 @@ The commands are:
 - stop [message]
   Stop the test early (marking it as passing), including the message if given.
 
+- symlink file -> target
+  Create file as a symlink to target. The -> (like in ls -l output) is required.
+
 When TestScript runs a script and the script fails, by default TestScript shows
 the execution of the most recent phase of the script (since the last # comment)
 and only shows the # comments for earlier phases. For example, here is a

src/cmd/go/testdata/script/mod_convert_dep.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/Gopkg.lock --
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_git.txt

+env GO111MODULE=on
+
+# detect root of module tree as root of enclosing git repo
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/.git/config --
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_glide.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/glide.lock --
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_glockfile.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/GLOCKFILE --
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_godeps.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/Godeps/Godeps.json --
+{}
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_tsv.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/dependencies.tsv --
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_vendor_conf.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/vendor.conf --
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_vendor_json.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/vendor/vendor.json --
+{}
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_vendor_manifest.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/vendor/manifest --
+{}
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_convert_vendor_yml.txt

+env GO111MODULE=on
+
+cd $WORK/test/x
+go list -m all
+stdout '^m$'
+
+-- $WORK/test/vendor.yml --
+-- $WORK/test/x/x.go --
+package x // import "m/x"

src/cmd/go/testdata/script/mod_edit.txt

+env GO111MODULE=on
+
+# Test that go mod edits and related mod flags work.
+# Also test that they can use a dummy name that isn't resolvable. golang.org/issue/24100
+
+# go mod -init
+! go mod -init
+stderr 'cannot determine module path'
+! exists go.mod
+
+go mod -init -module x.x/y/z
+stderr 'creating new go.mod: module x.x/y/z'
+cmp go.mod $WORK/go.mod.init
+
+! go mod -init
+cmp go.mod $WORK/go.mod.init
+
+# go mod edits
+go mod -droprequire=x.1 -require=x.1@v1.0.0 -require=x.2@v1.1.0 -droprequire=x.2 -exclude='x.1 @ v1.2.0' -exclude=x.1@v1.2.1 -replace=x.1@v1.3.0=y.1@v1.4.0 -replace='x.1@v1.4.0 = ../z'
+cmp go.mod $WORK/go.mod.edit1
+go mod -droprequire=x.1 -dropexclude=x.1@v1.2.1 -dropreplace=x.1@v1.3.0 -require=x.3@v1.99.0
+cmp go.mod $WORK/go.mod.edit2
+
+# go mod -json
+go mod -json
+cmp stdout $WORK/go.mod.json
+
+# go mod -replace
+go mod -replace=x.1@v1.3.0=y.1/v2@v2.3.5 -replace=x.1@v1.4.0=y.1/v2@v2.3.5
+cmp go.mod $WORK/go.mod.edit3
+go mod -replace=x.1=y.1/v2@v2.3.6
+cmp go.mod $WORK/go.mod.edit4
+
+# go mod -packages
+go mod -packages
+cmp stdout $WORK/go.mod.packages
+
+# go mod -fmt
+cp $WORK/go.mod.badfmt go.mod
+go mod -fmt
+cmp go.mod $WORK/go.mod.edit4
+
+-- x.go --
+package x
+
+-- w/w.go --
+package w
+
+-- $WORK/go.mod.init --
+module x.x/y/z
+-- $WORK/go.mod.edit1 --
+module x.x/y/z
+
+require x.1 v1.0.0
+
+exclude (
+	x.1 v1.2.0
+	x.1 v1.2.1
+)
+
+replace (
+	x.1 v1.3.0 => y.1 v1.4.0
+	x.1 v1.4.0 => ../z
+)
+-- $WORK/go.mod.edit2 --
+module x.x/y/z
+
+exclude x.1 v1.2.0
+
+replace x.1 v1.4.0 => ../z
+
+require x.3 v1.99.0
+-- $WORK/go.mod.json --
+{
+	"Module": {
+		"Path": "x.x/y/z"
+	},
+	"Require": [
+		{
+			"Path": "x.3",
+			"Version": "v1.99.0"
+		}
+	],
+	"Exclude": [
+		{
+			"Path": "x.1",
+			"Version": "v1.2.0"
+		}
+	],
+	"Replace": [
+		{
+			"Old": {
+				"Path": "x.1",
+				"Version": "v1.4.0"
+			},
+			"New": {
+				"Path": "../z"
+			}
+		}
+	]
+}
+-- $WORK/go.mod.edit3 --
+module x.x/y/z
+
+exclude x.1 v1.2.0
+
+replace (
+	x.1 v1.3.0 => y.1/v2 v2.3.5
+	x.1 v1.4.0 => y.1/v2 v2.3.5
+)
+
+require x.3 v1.99.0
+-- $WORK/go.mod.edit4 --
+module x.x/y/z
+
+exclude x.1 v1.2.0
+
+replace x.1 => y.1/v2 v2.3.6
+
+require x.3 v1.99.0
+-- $WORK/go.mod.packages --
+x.x/y/z
+x.x/y/z/w
+-- $WORK/go.mod.badfmt --
+module     x.x/y/z
+
+exclude x.1     v1.2.0
+
+replace x.1    =>   y.1/v2 v2.3.6
+
+require x.3   v1.99.0

src/cmd/go/testdata/script/mod_find.txt

+env GO111MODULE=on
+
+# Derive module path from import comment.
+# TODO SHOULD NOT NEED ENV VAR YET
+cd $WORK/x
+exists x.go
+go mod -init
+stderr 'module x'
+
+# Import comment works even with CRLF line endings.
+rm go.mod
+addcrlf x.go
+go mod -init
+stderr 'module x'
+
+# Derive module path from location inside GOPATH.
+cd $GOPATH/src/example.com/x/y
+go mod -init
+stderr 'module example.com/x/y$'
+rm go.mod
+
+# Module path from Godeps/Godeps.json overrides GOPATH.
+cd $GOPATH/src/example.com/x/y/z
+go mod -init
+stderr 'unexpected.com/z'
+rm go.mod
+
+# Empty directory outside GOPATH fails.
+mkdir $WORK/empty
+cd $WORK/empty
+! go mod -init
+stderr 'cannot determine module path for source directory'
+rm go.mod
+
+# Empty directory inside GOPATH/src uses location inside GOPATH.
+mkdir $GOPATH/src/empty
+cd $GOPATH/src/empty
+go mod -init
+stderr 'empty'
+rm go.mod
+
+[!symlink] stop
+
+# gplink1/src/empty where gopathlink -> GOPATH
+symlink $WORK/gopathlink -> gopath
+cd $WORK/gopathlink/src/empty
+go mod -init
+rm go.mod
+
+# GOPATH/src/link where link -> out of GOPATH
+symlink $GOPATH/src/link -> $WORK/empty
+cd $WORK/empty
+! go mod -init
+cd $GOPATH/src/link
+go mod -init
+stderr link
+rm go.mod
+
+# GOPATH/src/empty where GOPATH itself is a symlink
+env GOPATH=$WORK/gopathlink
+cd $GOPATH/src/empty
+go mod -init
+rm go.mod
+cd $WORK/gopath/src/empty
+go mod -init
+rm go.mod
+
+# GOPATH/src/link where GOPATH and link are both symlinks
+cd $GOPATH/src/link
+go mod -init
+stderr link
+rm go.mod
+
+# Too hard: doesn't match unevaluated nor completely evaluated. (Only partially evaluated.)
+# Whether this works depends on which OS we are running on.
+# cd $WORK/gopath/src/link
+# ! go mod -init
+
+-- $WORK/x/x.go --
+package x // import "x"
+
+-- $GOPATH/src/example.com/x/y/y.go --
+package y
+-- $GOPATH/src/example.com/x/y/z/z.go --
+package z
+-- $GOPATH/src/example.com/x/y/z/Godeps/Godeps.json --
+{"ImportPath": "unexpected.com/z"}

src/cmd/go/testdata/script/mod_vendor.txt

+env GO111MODULE=on
+
+go list -m all
+stdout '^x v1.0.0 => ./x'
+stdout '^w'
+
+[!short] go build
+[!short] ! go build -getmode=vendor
+
+go list -f {{.Dir}} x
+stdout 'src[\\/]x'
+
+go mod -vendor -v
+stderr '^# x v1.0.0 => ./x'
+stderr '^x'
+stderr '^# y v1.0.0 => ./y'
+stderr '^y'
+stderr '^# z v1.0.0 => ./z'
+stderr '^z'
+! stderr '^w'
+
+go list -f {{.Dir}} x
+stdout 'src[\\/]x'
+
+go list -f {{.Dir}} -m x
+stdout 'src[\\/]x'
+
+go list -getmode=vendor -f {{.Dir}} x
+stdout 'src[\\/]vendor[\\/]x'
+
+go list -getmode=vendor -f {{.Dir}} -m x
+stdout 'src[\\/]vendor[\\/]x'
+
+go list -f {{.Dir}} -m w
+stdout 'src[\\/]w'
+
+! go list -getmode=vendor -f {{.Dir}} w
+stderr 'src[\\/]vendor[\\/]w'
+
+! exists vendor/x/testdata
+! exists vendor/a/foo/bar/b/main_test.go
+
+exists vendor/a/foo/AUTHORS.txt
+exists vendor/a/foo/CONTRIBUTORS
+exists vendor/a/foo/LICENSE
+exists vendor/a/foo/PATENTS
+exists vendor/a/foo/COPYING
+exists vendor/a/foo/COPYLEFT
+exists vendor/x/NOTICE!
+exists vendor/mysite/myname/mypkg/LICENSE.txt
+
+! exists vendor/a/foo/licensed-to-kill
+! exists vendor/w
+! exists vendor/w/LICENSE
+! exists vendor/x/x2
+! exists vendor/x/x2/LICENSE
+
+[short] stop
+
+go build
+go build -getmode=vendor
+go test -getmode=vendor . ./subdir
+go test -getmode=vendor ./...
+
+-- go.mod --
+module m
+
+require (
+	a v1.0.0
+	mysite/myname/mypkg v1.0.0
+	w v1.0.0 // indirect
+	x v1.0.0
+	y v1.0.0
+	z v1.0.0
+)
+
+replace (
+	a v1.0.0 => ./a
+	mysite/myname/mypkg v1.0.0 => ./mypkg
+	w v1.0.0 => ./w
+	x v1.0.0 => ./x
+	y v1.0.0 => ./y
+	z v1.0.0 => ./z
+)
+
+-- a/foo/AUTHORS.txt --
+-- a/foo/CONTRIBUTORS --
+-- a/foo/LICENSE --
+-- a/foo/PATENTS --
+-- a/foo/COPYING --
+-- a/foo/COPYLEFT --
+-- a/foo/licensed-to-kill --
+-- w/LICENSE --
+-- x/NOTICE! --
+-- x/x2/LICENSE --
+-- mypkg/LICENSE.txt --
+
+-- a/foo/bar/b/main.go --
+package b
+-- a/foo/bar/b/main_test.go --
+package b
+
+import (
+	"os"
+	"testing"
+)
+
+func TestDir(t *testing.T) {
+	if _, err := os.Stat("../testdata/1"); err != nil {
+		t.Fatalf("testdata: %v", err)
+	}
+}
+-- a/foo/bar/c/main.go --
+package c
+-- a/foo/bar/c/main_test.go --
+package c
+
+import (
+	"os"
+	"testing"
+)
+
+func TestDir(t *testing.T) {
+	if _, err := os.Stat("../../../testdata/1"); err != nil {
+		t.Fatalf("testdata: %v", err)
+	}
+	if _, err := os.Stat("./testdata/1"); err != nil {
+		t.Fatalf("testdata: %v", err)
+	}
+}
+-- a/foo/bar/c/testdata/1 --
+-- a/foo/bar/testdata/1 --
+-- a/go.mod --
+module a
+-- a/main.go --
+package a
+-- a/main_test.go --
+package a
+
+import (
+	"os"
+	"testing"
+)
+
+func TestDir(t *testing.T) {
+	if _, err := os.Stat("./testdata/1"); err != nil {
+		t.Fatalf("testdata: %v", err)
+	}
+}
+-- a/testdata/1 --
+-- appengine.go --
+// +build appengine
+
+package m
+
+import _ "appengine"
+import _ "appengine/datastore"
+-- mypkg/go.mod --
+module me
+-- mypkg/mydir/d.go --
+package mydir
+-- subdir/v1_test.go --
+package m
+
+import _ "mysite/myname/mypkg/mydir"
+-- testdata1.go --
+package m
+
+import _ "a"
+-- testdata2.go --
+package m
+
+import _ "a/foo/bar/b"
+import _ "a/foo/bar/c"
+-- v1.go --
+package m
+
+import _ "x"
+-- v2.go --
+// +build abc
+
+package mMmMmMm
+
+import _ "y"
+-- v3.go --
+// +build !abc
+
+package m
+
+import _ "z"
+-- v4.go --
+// +build notmytag
+
+package m
+
+import _ "x/x1"
+-- w/go.mod --
+module w
+-- w/w.go --
+package w
+-- x/go.mod --
+module x
+-- x/testdata/x.txt --
+placeholder - want directory with no go files
+-- x/x.go --
+package x
+-- x/x1/x1.go --
+// +build notmytag
+
+package x1
+-- x/x2/dummy.txt --
+dummy
+-- x/x_test.go --
+package x
+
+import _ "w"
+-- y/go.mod --
+module y
+-- y/y.go --
+package y
+-- z/go.mod --
+module z
+-- z/z.go --
+package z