Corrected default null replacement value used

Author: inv-jishnu

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/producer/CsvProducerTask.java

@@ -118,10 +118,10 @@ private String convertResultToCsv(Result result) {
    */
   private String convertToString(Result result, String columnName, DataType dataType) {
     if (result.isNull(columnName)) {
-      // "/N" is added when a column of text data type has null value. This is only converted for
+      // "\N" is added when a column of text data type has null value. This is only converted for
       // CSV files
       if (dataType.equals(DataType.TEXT)) {
-        return "/N";
+        return "\\N";
       }
       return null;
     }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/util/ColumnUtils.java

@@ -84,7 +84,7 @@ public static Column<?> createColumnFromValue(
       throws ColumnParsingException {
     String columnName = columnInfo.getColumnName();
     if (value != null && (!dataType.equals(DataType.TEXT) && value.equalsIgnoreCase("null"))
-        || (dataType.equals(DataType.TEXT) && "/N".equals(value))) {
+        || (dataType.equals(DataType.TEXT) && "\\N".equals(value))) {
       value = null;
     }
     try {

data-loader/core/src/test/java/com/scalar/db/dataloader/core/dataexport/producer/CsvProducerTaskTest.java

@@ -122,7 +122,7 @@ void process_withValidResultList_withPartialProjectionsAndMetadata_shouldReturnV
   void
       process_withValidResultListWithTextFieldWithNullValue_shouldReturnValidCsvStringWithCustomNullValueForTextField() {
     String expectedOutput =
-        "9007199254740992,2147483647,true,0.000000000000000000000000000000000000000000001401298464324817,0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000049,/N,YmxvYiB0ZXN0IHZhbHVl,2000-01-01,01:01:01,2000-01-01T01:01,1970-01-21T03:20:41.740Z,0.000000000000000000000000000000000000000000001401298464324817,0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000049,test value,YmxvYiB0ZXN0IHZhbHVl,txt value 464654654,2147483647,2147483647,9007199254740992,9007199254740992,test value,2147483647,2147483647,9007199254740992,9007199254740992";
+        "9007199254740992,2147483647,true,0.000000000000000000000000000000000000000000001401298464324817,0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000049,\\N,YmxvYiB0ZXN0IHZhbHVl,2000-01-01,01:01:01,2000-01-01T01:01,1970-01-21T03:20:41.740Z,0.000000000000000000000000000000000000000000001401298464324817,0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000049,test value,YmxvYiB0ZXN0IHZhbHVl,txt value 464654654,2147483647,2147483647,9007199254740992,9007199254740992,test value,2147483647,2147483647,9007199254740992,9007199254740992";
     Map<String, Column<?>> values = UnitTestUtils.createTestValues();
     String textColName = "col6";
     Column<?> col = values.get(textColName);

data-loader/core/src/test/java/com/scalar/db/dataloader/core/util/ColumnUtilsTest.java

@@ -315,12 +315,12 @@ void createColumnFromValue_valueIsNullString_shouldRemainLiteralForTextType()
    * treated as an actual null value
    */
   @Test
-  void createColumnFromValue_valueIsCustomNullValue_shouldRemainLiteralForTextType()
+  void createColumnFromValue_customNullValueForText_shouldBeConvertedToNull()
       throws ColumnParsingException {
     String columnName = "textColumn";
     ColumnInfo columnInfo = ColumnInfo.builder().columnName(columnName).build();
 
-    Column<?> textCol = ColumnUtils.createColumnFromValue(DataType.TEXT, columnInfo, "/N");
+    Column<?> textCol = ColumnUtils.createColumnFromValue(DataType.TEXT, columnInfo, "\\N");
     assertEquals(TextColumn.ofNull(columnName), textCol);
   }
 }