tests: invert ResetTmpDir argument

As reverse also does not want a diriv file, the "plaintextNames"
argument became a misnomer.

tests/example_filesystems/example_filesystems_test.go

@@ -32,7 +32,7 @@ func TestMain(m *testing.M) {
 		if testing.Verbose() {
 			fmt.Printf("example_filesystems: testing with %q\n", opensslOpt)
 		}
-		test_helpers.ResetTmpDir(true)
+		test_helpers.ResetTmpDir(false)
 		r := m.Run()
 		if r != 0 {
 			os.Exit(r)

tests/matrix/matrix_test.go

@@ -65,8 +65,7 @@ func TestMain(m *testing.M) {
 			j, _ := json.Marshal(testcase)
 			fmt.Printf("matrix: testcase = %s\n", string(j))
 		}
-		testcase.Plaintextnames = testcase.Plaintextnames
-		test_helpers.ResetTmpDir(testcase.Plaintextnames)
+		test_helpers.ResetTmpDir(!testcase.Plaintextnames)
 		opts := []string{"-zerokey"}
 		opts = append(opts, fmt.Sprintf("-openssl=%v", testcase.Openssl))
 		opts = append(opts, fmt.Sprintf("-plaintextnames=%v", testcase.Plaintextnames))

tests/test_helpers/helpers.go

@@ -48,7 +48,7 @@ func init() {
 // |-- DefaultPlainDir
 // *-- DefaultCipherDir
 //     *-- gocryptfs.diriv
-func ResetTmpDir(plaintextNames bool) {
+func ResetTmpDir(createDirIV bool) {
 	// Try to unmount and delete everything
 	entries, err := ioutil.ReadDir(TmpDir)
 	if err == nil {
@@ -83,7 +83,7 @@ func ResetTmpDir(plaintextNames bool) {
 	if err != nil {
 		panic(err)
 	}
-	if !plaintextNames {
+	if createDirIV {
 		err = nametransform.WriteDirIV(DefaultCipherDir)
 		if err != nil {
 			panic(err)