cmd/go: honor buildflags in go test.

Fixes #3196.

R=golang-dev, rsc
CC=golang-dev, remy
https://golang.org/cl/5725044

src/cmd/go/build.go

@@ -100,6 +100,7 @@ var buildContext = build.Default
 
 // addBuildFlags adds the flags common to the build and install commands.
 func addBuildFlags(cmd *Command) {
+	// NOTE: If you add flags here, also add them to testflag.go.
 	cmd.Flag.BoolVar(&buildA, "a", false, "")
 	cmd.Flag.BoolVar(&buildN, "n", false, "")
 	cmd.Flag.IntVar(&buildP, "p", buildP, "")

src/cmd/go/test.go

@@ -192,8 +192,6 @@ See the documentation of the testing package for more information.
 var (
 	testC            bool     // -c flag
 	testI            bool     // -i flag
-	testP            int      // -p flag
-	testX            bool     // -x flag
 	testV            bool     // -v flag
 	testFiles        []string // -file flag(s)  TODO: not respected
 	testTimeout      string   // -timeout flag
@@ -241,11 +239,6 @@ func runTest(cmd *Command, args []string) {
 	testStreamOutput = len(pkgArgs) == 0 || testBench ||
 		(len(pkgs) <= 1 && testShowPass)
 
-	buildX = testX
-	if testP > 0 {
-		buildP = testP
-	}
-
 	var b builder
 	b.init()
 
@@ -639,6 +632,9 @@ func (b *builder) runTest(a *action) error {
 
 // cleanTest is the action for cleaning up after a test.
 func (b *builder) cleanTest(a *action) error {
+	if buildWork {
+		return nil
+	}
 	run := a.deps[0]
 	testDir := filepath.Join(b.work, filepath.FromSlash(run.p.ImportPath+"/_test"))
 	os.RemoveAll(testDir)

src/cmd/go/testflag.go

@@ -47,7 +47,7 @@ func testUsage() {
 // testFlagSpec defines a flag we know about.
 type testFlagSpec struct {
 	name       string
-	isBool     bool
+	boolVar    *bool
 	passToTest bool // pass to Test
 	multiOK    bool // OK to have multiple instances
 	present    bool // flag has been seen
@@ -56,11 +56,20 @@ type testFlagSpec struct {
 // testFlagDefn is the set of flags we process.
 var testFlagDefn = []*testFlagSpec{
 	// local.
-	{name: "c", isBool: true},
+	{name: "c", boolVar: &testC},
 	{name: "file", multiOK: true},
-	{name: "i", isBool: true},
+	{name: "i", boolVar: &testI},
+
+	// build flags.
+	{name: "a", boolVar: &buildA},
+	{name: "n", boolVar: &buildN},
 	{name: "p"},
-	{name: "x", isBool: true},
+	{name: "x", boolVar: &buildX},
+	{name: "work", boolVar: &buildWork},
+	{name: "gcflags"},
+	{name: "ldflags"},
+	{name: "gccgoflags"},
+	{name: "tags"},
 
 	// passed to 6.out, adding a "test." prefix to the name if necessary: -v becomes -test.v.
 	{name: "bench", passToTest: true},
@@ -71,9 +80,9 @@ var testFlagDefn = []*testFlagSpec{
 	{name: "memprofilerate", passToTest: true},
 	{name: "parallel", passToTest: true},
 	{name: "run", passToTest: true},
-	{name: "short", isBool: true, passToTest: true},
+	{name: "short", boolVar: new(bool), passToTest: true},
 	{name: "timeout", passToTest: true},
-	{name: "v", isBool: true, passToTest: true},
+	{name: "v", boolVar: &testV, passToTest: true},
 }
 
 // testFlags processes the command line, grabbing -x and -c, rewriting known flags
@@ -118,16 +127,19 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 			continue
 		}
 		switch f.name {
-		case "c":
-			setBoolFlag(&testC, value)
-		case "i":
-			setBoolFlag(&testI, value)
+		// bool flags.
+		case "a", "c", "i", "n", "x", "v", "work":
+			setBoolFlag(f.boolVar, value)
 		case "p":
-			setIntFlag(&testP, value)
-		case "x":
-			setBoolFlag(&testX, value)
-		case "v":
-			setBoolFlag(&testV, value)
+			setIntFlag(&buildP, value)
+		case "gcflags":
+			buildGcflags = strings.Fields(value)
+		case "ldflags":
+			buildLdflags = strings.Fields(value)
+		case "gccgoflags":
+			buildGccgoflags = strings.Fields(value)
+		case "tags":
+			buildContext.BuildTags = strings.Fields(value)
 		case "file":
 			testFiles = append(testFiles, value)
 		case "bench":
@@ -172,7 +184,7 @@ func testFlag(args []string, i int) (f *testFlagSpec, value string, extra bool)
 	for _, f = range testFlagDefn {
 		if name == f.name {
 			// Booleans are special because they have modes -x, -x=true, -x=false.
-			if f.isBool {
+			if f.boolVar != nil {
 				if equals < 0 { // otherwise, it's been set and will be verified in setBoolFlag
 					value = "true"
 				} else {