cmd/go: go test builtin fails

[dvyukov]

on bedfa4e

$ go test ./...
# builtin.test
../../../tmp/go-build/go-build854466004/b073_testmain.go:12:2: can't find import: "builtin"

Does it have some special handling? Should we skip its testing?

[ianlancetaylor]

There are no tests of that package. It's not a real package, just documentation. What's broken here is that go test builtin tries to build a test binary, although there are no tests. This was almost certainly broken by https://golang.org/cl/115095, for #24570.

CC @kyroy

[wingyplus]

I found that it back to normal when revert come changes from ebb8a1f.

diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index aff5ff2c9d..744a1fa983 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -781,6 +781,13 @@ var windowsBadWords = []string{
 }
 
 func builderTest(b *work.Builder, p *load.Package) (buildAction, runAction, printAction *work.Action, err error) {
+	if len(p.TestGoFiles)+len(p.XTestGoFiles) == 0 {
+		build := b.CompileAction(work.ModeBuild, work.ModeBuild, p)
+		run := &work.Action{Mode: "test run", Package: p, Deps: []*work.Action{build}}
+		addTestVet(b, p, run, nil)
+		print := &work.Action{Mode: "test print", Func: builderNoTest, Package: p, Deps: []*work.Action{run}}
+		return build, run, print, nil
+	}
 	// Build Package structs describing:
 	//	pmain - pkg.test binary
 	//	ptest - package + test files
@@ -1592,3 +1599,15 @@ func builderPrintTest(b *work.Builder, a *work.Action) error {
 	}
 	return nil
 }
+
+// builderNoTest is the action for testing a package with no test files.
+func builderNoTest(b *work.Builder, a *work.Action) error {
+	var stdout io.Writer = os.Stdout
+	if testJSON {
+		json := test2json.NewConverter(lockedStdout{}, a.Package.ImportPath, test2json.Timestamp)
+		defer json.Close()
+		stdout = json
+	}
+	fmt.Fprintf(stdout, "?   \t%s\t[no test files]\n", a.Package.ImportPath)
+	return nil
+}

[ysmolski]

That revert has reached the tip. This cannot be reproduced on Darwin (el capitan).

[bcmills]

Agreed; seems to be fixed.

~/go/src$ go version
go version devel +3fcfb1f573 Mon Jul 16 15:32:40 2018 +0000 linux/amd64

~/go/src$ go test builtin
?       builtin [no test files]