cmd/go: show FAIL for errors during test setup

For example, if an x_test.go file contains a syntax error,
b.test fails with an error message. But it wasn't printing
the same FAIL line that a build failure later would print.
This makes all the test failures that happen (once we
decide to start running tests) consistently say FAIL.

Fixes #4701.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13431044

src/cmd/go/test.bash

@@ -104,6 +104,19 @@ cp -R testdata/local "testdata/$bad"
 testlocal "$bad" 'with bad characters in path'
 rm -rf "testdata/$bad"
 
+TEST error message for syntax error in test go file says FAIL
+export GOPATH=$(pwd)/testdata
+if ./testgo test syntaxerror 2>testdata/err; then
+	echo 'go test syntaxerror succeeded'
+	ok=false
+elif ! grep FAIL testdata/err >/dev/null; then
+	echo 'go test did not say FAIL:'
+	cat testdata/err
+	ok=false
+fi
+rm -f ./testdata/err
+unset GOPATH
+
 # Test tests with relative imports.
 TEST relative imports '(go test)'
 if ! ./testgo test ./testdata/testimport; then

src/cmd/go/test.go

@@ -423,10 +423,12 @@ func runTest(cmd *Command, args []string) {
 			if strings.HasPrefix(str, "\n") {
 				str = str[1:]
 			}
+			failed := fmt.Sprintf("FAIL\t%s [setup failed]\n", p.ImportPath)
+
 			if p.ImportPath != "" {
-				errorf("# %s\n%s", p.ImportPath, str)
+				errorf("# %s\n%s\n%s", p.ImportPath, str, failed)
 			} else {
-				errorf("%s", str)
+				errorf("%s\n%s", str, failed)
 			}
 			continue
 		}

src/cmd/go/testdata/src/syntaxerror/x.go

+package p

src/cmd/go/testdata/src/syntaxerror/x_test.go

+package p
+
+func f() (x.y, z int) {
+}