Fixes assertion for TTL duration in WriteOptionsBuilder.

Closes #1248
Original pull request: #1249.

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/cql/WriteOptions.java

@@ -143,6 +143,7 @@ public class WriteOptions extends QueryOptions {
 	 *
 	 * @author Mark Paluch
 	 * @author Lukasz Antoniak
+	 * @author Thomas Strauß
 	 * @since 1.5
 	 */
 	public static class WriteOptionsBuilder extends QueryOptionsBuilder {
@@ -291,7 +292,7 @@ public class WriteOptions extends QueryOptions {
 		public WriteOptionsBuilder ttl(Duration ttl) {
 
 			Assert.notNull(ttl, "TTL must not be null");
-			Assert.isTrue(!ttl.isNegative(), "TTL must be greater than equal to zero");
+			Assert.isTrue(!ttl.isNegative() && !ttl.isZero(), "TTL must be greater than equal to zero");
 
 			this.ttl = ttl;
 

spring-data-cassandra/src/test/java/org/springframework/data/cassandra/core/cql/WriteOptionsUnitTests.java

@@ -22,6 +22,7 @@ import java.time.Duration;
 import java.time.Instant;
 import java.time.LocalDateTime;
 import java.time.ZoneOffset;
+import java.time.temporal.ChronoUnit;
 
 import org.junit.jupiter.api.Test;
 
@@ -33,6 +34,7 @@ import com.datastax.oss.driver.api.core.DefaultConsistencyLevel;
  *
  * @author Mark Paluch
  * @author Sam Lightfoot
+ * @author Thomas Strauß
  */
 class WriteOptionsUnitTests {
 
@@ -106,4 +108,32 @@ class WriteOptionsUnitTests {
 				CqlIdentifier.fromCql("routing_keyspace"));
 		assertThat(writeOptions.getRoutingKey()).isEqualTo(ByteBuffer.allocate(1));
 	}
+
+	@Test // GH-1248
+	void buildWriteOptionsWithTtlDurationZero() {
+		try {
+			WriteOptions writeOptions = WriteOptions.builder()
+					.ttl(Duration.ZERO)
+					.build();
+			
+			fail("WiteOptionsBuilder must not allow zero TTL");
+		}
+		catch (Exception e) {
+			// expected behavior
+		}
+	}
+
+	@Test // GH-1248
+	void buildWriteOptionsWithTtlNegativeDuration() {
+		try {
+			WriteOptions writeOptions = WriteOptions.builder()
+					.ttl(Duration.of(-1, ChronoUnit.MICROS))
+					.build();
+
+			fail("WiteOptionsBuilder must not allow negative TTL");
+		}
+		catch (Exception e) {
+			// expected behavior
+		}
+	}
 }