improve fileInit func by not loading unspecified data (#189)

* improve fileInit func by not loading unsepcified data

pkg/exprhelpers/exprlib.go

@@ -60,12 +60,13 @@ func FileInit(fileFolder string, filename string, fileType string) error {
 	}
 	defer file.Close()
 
+	if fileType == "" {
+		log.Debugf("ignored file %s%s because no type specified", fileFolder, filename)
+		return nil
+	}
 	if _, ok := dataFile[filename]; !ok {
 		dataFile[filename] = []string{}
 	}
-	if fileType == "" {
-		fileType = "string"
-	}
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
 		if strings.HasPrefix(scanner.Text(), "#") { // allow comments

pkg/exprhelpers/exprlib_test.go

@@ -165,7 +165,7 @@ func TestFile(t *testing.T) {
 		log.Fatalf(err.Error())
 	}
 
-	err := FileInit(TestFolder, "test_data.txt", "")
+	err := FileInit(TestFolder, "test_data.txt", "string")
 	if err != nil {
 		log.Fatalf(err.Error())
 	}