Resetting the getVersionFromTablet variable for unit test.

go/vt/wrangler/testlib/version_test.go

@@ -43,6 +43,10 @@ func expvarHandler(gitRev *string) func(http.ResponseWriter, *http.Request) {
 }
 
 func TestVersion(t *testing.T) {
+	// We need to run this test with the /debug/vars version of the
+	// plugin.
+	wrangler.ResetDebugVarsGetVersion()
+
 	// Initialize our environment
 	ts := zktopo.NewTestServer(t, []string{"cell1", "cell2"})
 	wr := wrangler.New(logutil.NewConsoleLogger(), ts, tmclient.NewTabletManagerClient(), time.Second)

go/vt/wrangler/version.go

@@ -18,7 +18,7 @@ import (
 	"golang.org/x/net/context"
 )
 
-var getVersionFromTablet = func(tabletAddr string) (string, error) {
+var getVersionFromTabletDebugVars = func(tabletAddr string) (string, error) {
 	resp, err := http.Get("http://" + tabletAddr + "/debug/vars")
 	if err != nil {
 		return "", err
@@ -44,6 +44,16 @@ var getVersionFromTablet = func(tabletAddr string) (string, error) {
 	return version, nil
 }
 
+var getVersionFromTablet = getVersionFromTabletDebugVars
+
+// ResetDebugVarsGetVersion is used by tests to reset the
+// getVersionFromTablet variable to the default one. That way we can
+// run the unit tests in testlib/ even when another implementation of
+// getVersionFromTablet is used.
+func ResetDebugVarsGetVersion() {
+	getVersionFromTablet = getVersionFromTabletDebugVars
+}
+
 // GetVersion returns the version string from a tablet
 func (wr *Wrangler) GetVersion(ctx context.Context, tabletAlias topo.TabletAlias) (string, error) {
 	tablet, err := wr.ts.GetTablet(ctx, tabletAlias)