added tests for LowCardinality()

Author: chernser

client-v2/src/test/java/com/clickhouse/client/insert/SamplePOJO.java

@@ -85,6 +85,8 @@ public class SamplePOJO {
     private ClickHouseBitmap groupBitmapUint32;
     private ClickHouseBitmap groupBitmapUint64;
 
+    private String keyword;
+
     public SamplePOJO() {
         final Random random = new Random();
         byteValue = (byte) random.nextInt();
@@ -180,6 +182,8 @@ public SamplePOJO() {
 
         groupBitmapUint32 = ClickHouseBitmap.wrap(random.ints(5, Integer.MAX_VALUE - 100, Integer.MAX_VALUE).toArray());
         groupBitmapUint64 = ClickHouseBitmap.wrap(random.longs(5, Long.MAX_VALUE - 100, Long.MAX_VALUE).toArray());
+
+        keyword = "database";
     }
 
     public byte getByteValue() {
@@ -574,6 +578,14 @@ public void setGroupBitmapUint64(ClickHouseBitmap groupBitmapUint64) {
         this.groupBitmapUint64 = groupBitmapUint64;
     }
 
+    public String getKeyword() {
+        return keyword;
+    }
+
+    public void setKeyword(String keyword) {
+        this.keyword = keyword;
+    }
+
     @Override
     public String toString() {
         return "SamplePOJO{" +
@@ -683,7 +695,8 @@ public static String generateTableCreateSQL(String tableName) {
                 "nested Nested (innerInt Int32, innerString String, " +
                 "innerNullableInt Nullable(Int32)), " +
                 "groupBitmapUint32 AggregateFunction(groupBitmap, UInt32), " +
-                "groupBitmapUint64 AggregateFunction(groupBitmap, UInt64) " +
+                "groupBitmapUint64 AggregateFunction(groupBitmap, UInt64), " +
+                "keyword LowCardinality(String) " +
                 ") ENGINE = MergeTree ORDER BY ()";
     }
 }

client-v2/src/test/java/com/clickhouse/client/query/QueryTests.java

@@ -62,6 +62,7 @@
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -2000,4 +2001,21 @@ public void testServerTimezone() throws Exception {
             Assert.assertEquals(serverUtcTime.withZoneSameInstant(ZoneId.of("America/New_York")), serverEstTime);
         }
     }
+
+    @Test(groups = {"integration"})
+    public void testLowCardinalityValues() throws Exception {
+        final String table = "test_low_cardinality_values";
+        final String tableCreate = "CREATE TABLE " + table + "(rowID Int32, keyword LowCardinality(String)) Engine = MergeTree ORDER BY ()";
+
+        client.execute("DROP TABLE IF EXISTS " + table);
+        client.execute(tableCreate);
+
+        client.execute("INSERT INTO " + table + " VALUES (0, 'db'), (1, 'fast'), (2, 'not a java')");
+        String[] values = new String[] {"db", "fast", "not a java"};
+        Collection<GenericRecord> records = client.queryAll("SELECT * FROM " + table);
+        for (GenericRecord record : records) {
+            int rowId = record.getInteger("rowID");
+            Assert.assertEquals(record.getString("keyword"), values[rowId]);
+        }
+    }
 }