fix unit test

pkg/minikube/out/register/json_test.go

@@ -97,15 +97,20 @@ func TestErrorExitCode(t *testing.T) {
 	}
 
 	PrintErrorExitCode("error", 5, map[string]string{"a": "b"}, map[string]string{"c": "d"})
+	actual := buf.String()
+	if actual != expected {
+		t.Fatalf("expected didn't match actual:\nExpected:\n%v\n\nActual:\n%v", expected, actual)
+	}
+}
 func TestWarning(t *testing.T) {
 	expected := `{"data":{"message":"warning"},"datacontenttype":"application/json","id":"random-id","source":"https://minikube.sigs.k8s.io/","specversion":"1.0","type":"io.k8s.sigs.minikube.warning"}`
 	expected += "\n"
 
 	buf := bytes.NewBuffer([]byte{})
-	outputFile = buf
-	defer func() { outputFile = os.Stdout }()
+	OutputFile = buf
+	defer func() { OutputFile = os.Stdout }()
 
-	getUUID = func() string {
+	GetUUID = func() string {
 		return "random-id"
 	}
 

test/integration/json_output_test.go

@@ -65,6 +65,8 @@ func TestJSONOutputError(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), Minutes(2))
 	defer Cleanup(t, profile, cancel)
 
+	// force a failure via --driver=fail so that we can make sure errors
+	// are printed as expected
 	startArgs := []string{"start", "-p", profile, "--memory=2200", "--output=json", "--wait=true", "--driver=fail"}
 
 	rr, err := Run(t, exec.CommandContext(ctx, Target(), startArgs...))