cmd/go, testing: add TB.ArtifactDir and -artifacts flag

Add TB.ArtifactDir, which returns a directory for a test to store
output files in. Add a -artifacts testflag which enables persistent
storage of artifacts in the output directory (-outputdir, or the
current directory by default).

Fixes #71287

Change-Id: I5f6515a6cd6c103f88588f4c033d5ea11ffd0c3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/696399
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alan Donovan <adonovan@google.com>

6 files changed, 41 insertions, 22 deletions

diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 19b48f0579..51f2223283 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -3244,6 +3244,10 @@
 // The following flags are recognized by the 'go test' command and
 // control the execution of any test:
 //
+//	-artifacts
+//	    Save test artifacts in the directory specified by -outputdir.
+//	    See 'go doc testing.T.ArtifactDir'.
+//
 //	-bench regexp
 //	    Run only those benchmarks matching a regular expression.
 //	    By default, no benchmarks are run.
@@ -3338,6 +3342,10 @@
 //	    This will only list top-level tests. No subtest or subbenchmarks will be
 //	    shown.
 //
+//	-outputdir directory
+//	    Place output files from profiling and test artifacts in the
+//	    specified directory, by default the directory in which "go test" is running.
+//
 //	-parallel n
 //	    Allow parallel execution of test functions that call t.Parallel, and
 //	    fuzz targets that call t.Parallel when running the seed corpus.
@@ -3449,10 +3457,6 @@
 //	    Sample 1 in n stack traces of goroutines holding a
 //	    contended mutex.
 //
-//	-outputdir directory
-//	    Place output files from profiling in the specified directory,
-//	    by default the directory in which "go test" is running.
-//
 //	-trace trace.out
 //	    Write an execution trace to the specified file before exiting.
 //
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index f895e3a246..9849ee138a 100644
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -649,6 +649,14 @@ func (t *testFuncs) ImportPath() string {
 	return pkg
 }
 
+func (t *testFuncs) ModulePath() string {
+	m := t.Package.Module
+	if m == nil {
+		return ""
+	}
+	return m.Path
+}
+
 // Covered returns a string describing which packages are being tested for coverage.
 // If the covered package is the same as the tested package, it returns the empty string.
 // Otherwise it is a comma-separated human-readable list of packages beginning with
@@ -836,6 +844,7 @@ func init() {
 	testdeps.CoverMarkProfileEmittedFunc = cfile.MarkProfileEmitted
 
 {{end}}
+	testdeps.ModulePath = {{.ModulePath | printf "%q"}}
 	testdeps.ImportPath = {{.ImportPath | printf "%q"}}
 }
 
diff --git a/src/cmd/go/internal/test/flagdefs.go b/src/cmd/go/internal/test/flagdefs.go
index 8aa0bfc2bf..b8b4bf649e 100644
--- a/src/cmd/go/internal/test/flagdefs.go
+++ b/src/cmd/go/internal/test/flagdefs.go
@@ -9,6 +9,7 @@ package test
 // passFlagToTest contains the flags that should be forwarded to
 // the test binary with the prefix "test.".
 var passFlagToTest = map[string]bool{
+	"artifacts":            true,
 	"bench":                true,
 	"benchmem":             true,
 	"benchtime":            true,
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 7a2963ff29..15ffc618c6 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -192,6 +192,10 @@ and -show_bytes options of pprof control how the information is presented.
 The following flags are recognized by the 'go test' command and
 control the execution of any test:
 
+	-artifacts
+	    Save test artifacts in the directory specified by -outputdir.
+	    See 'go doc testing.T.ArtifactDir'.
+
 	-bench regexp
 	    Run only those benchmarks matching a regular expression.
 	    By default, no benchmarks are run.
@@ -286,6 +290,10 @@ control the execution of any test:
 	    This will only list top-level tests. No subtest or subbenchmarks will be
 	    shown.
 
+	-outputdir directory
+	    Place output files from profiling and test artifacts in the
+	    specified directory, by default the directory in which "go test" is running.
+
 	-parallel n
 	    Allow parallel execution of test functions that call t.Parallel, and
 	    fuzz targets that call t.Parallel when running the seed corpus.
@@ -397,10 +405,6 @@ profile the tests during execution:
 	    Sample 1 in n stack traces of goroutines holding a
 	    contended mutex.
 
-	-outputdir directory
-	    Place output files from profiling in the specified directory,
-	    by default the directory in which "go test" is running.
-
 	-trace trace.out
 	    Write an execution trace to the specified file before exiting.
 
@@ -540,6 +544,7 @@ See the documentation of the testing package for more information.
 }
 
 var (
+	testArtifacts    bool                              // -artifacts flag
 	testBench        string                            // -bench flag
 	testC            bool                              // -c flag
 	testCoverPkgs    []*load.Package                   // -coverpkg flag
diff --git a/src/cmd/go/internal/test/testflag.go b/src/cmd/go/internal/test/testflag.go
index 983e8f56e9..fc2b22cb56 100644
--- a/src/cmd/go/internal/test/testflag.go
+++ b/src/cmd/go/internal/test/testflag.go
@@ -44,6 +44,7 @@ func init() {
 	// some of them so that cmd/go knows what to do with the test output, or knows
 	// to build the test in a way that supports the use of the flag.
 
+	cf.BoolVar(&testArtifacts, "artifacts", false, "")
 	cf.StringVar(&testBench, "bench", "", "")
 	cf.Bool("benchmem", false, "")
 	cf.String("benchtime", "", "")
@@ -392,7 +393,8 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 	// directory, but 'go test' defaults it to the working directory of the 'go'
 	// command. Set it explicitly if it is needed due to some other flag that
 	// requests output.
-	if testProfile() != "" && !outputDirSet {
+	needOutputDir := testProfile() != "" || testArtifacts
+	if needOutputDir && !outputDirSet {
 		injectedFlags = append(injectedFlags, "-test.outputdir="+testOutputDir.getAbs())
 	}
 
diff --git a/src/cmd/internal/test2json/test2json.go b/src/cmd/internal/test2json/test2json.go
index d08ef389f8..f28051e177 100644
--- a/src/cmd/internal/test2json/test2json.go
+++ b/src/cmd/internal/test2json/test2json.go
@@ -38,6 +38,7 @@ type event struct {
 	FailedBuild string     `json:",omitempty"`
 	Key         string     `json:",omitempty"`
 	Value       string     `json:",omitempty"`
+	Path        string     `json:",omitempty"`
 }
 
 // textBytes is a hack to get JSON to emit a []byte as a string
@@ -180,6 +181,7 @@ var (
 		[]byte("=== FAIL  "),
 		[]byte("=== SKIP  "),
 		[]byte("=== ATTR  "),
+		[]byte("=== ARTIFACTS "),
 	}
 
 	reports = [][]byte{
@@ -251,7 +253,6 @@ func (c *Converter) handleInputLine(line []byte) {
 	// "=== RUN   "
 	// "=== PAUSE "
 	// "=== CONT  "
-	actionColon := false
 	origLine := line
 	ok := false
 	indent := 0
@@ -273,7 +274,6 @@ func (c *Converter) handleInputLine(line []byte) {
 		}
 		for _, magic := range reports {
 			if bytes.HasPrefix(line, magic) {
-				actionColon = true
 				ok = true
 				break
 			}
@@ -296,16 +296,11 @@ func (c *Converter) handleInputLine(line []byte) {
 		return
 	}
 
-	// Parse out action and test name.
-	i := 0
-	if actionColon {
-		i = bytes.IndexByte(line, ':') + 1
-	}
-	if i == 0 {
-		i = len(updates[0])
-	}
-	action := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(string(line[4:i])), ":"))
-	name := strings.TrimSpace(string(line[i:]))
+	// Parse out action and test name from "=== ACTION: Name".
+	action, name, _ := strings.Cut(string(line[len("=== "):]), " ")
+	action = strings.TrimSuffix(action, ":")
+	action = strings.ToLower(action)
+	name = strings.TrimSpace(name)
 
 	e := &event{Action: action}
 	if line[0] == '-' { // PASS or FAIL report
@@ -336,7 +331,10 @@ func (c *Converter) handleInputLine(line []byte) {
 		c.output.write(origLine)
 		return
 	}
-	if action == "attr" {
+	switch action {
+	case "artifacts":
+		name, e.Path, _ = strings.Cut(name, " ")
+	case "attr":
 		var rest string
 		name, rest, _ = strings.Cut(name, " ")
 		e.Key, e.Value, _ = strings.Cut(rest, " ")