cmd/go: fix `go test -n`

The <importPath>/_test directory is not actually created in -n mode, so
`go test` fails to write _testmain.go.

Do not write _testmain.go if -n is passed.

Change-Id: I825d5040cacbc9d9a8c89443e5a3f83e6f210ce4
Reviewed-on: https://go-review.googlesource.com/15433
Reviewed-by: Andrew Gerrand <adg@golang.org>

diff --git a/src/cmd/go/test.go b/src/cmd/go/test.go
index ba1ab82680d9c06112d18c7b79f1d9ea9200298e..fa5ef3eb6571f6b017b19f00efa6de36e266b823 100644 (file)
--- a/src/cmd/go/test.go
+++ b/src/cmd/go/test.go
@@ -817,10 +817,12 @@ func (b *builder) test(p *Package) (buildAction, runAction, printAction *action,
                }
        }
 
-       // writeTestmain writes _testmain.go. This must happen after recompileForTest,
-       // because recompileForTest modifies XXX.
-       if err := writeTestmain(filepath.Join(testDir, "_testmain.go"), t); err != nil {
-               return nil, nil, nil, err
+       if !buildN {
+               // writeTestmain writes _testmain.go. This must happen after recompileForTest,
+               // because recompileForTest modifies XXX.
+               if err := writeTestmain(filepath.Join(testDir, "_testmain.go"), t); err != nil {
+                       return nil, nil, nil, err
+               }
        }
 
        computeStale(pmain)