Fix Array HSerializers

core/src/main/scala/com/azavea/hiveless/serializers/HSerializer.scala

@@ -16,7 +16,9 @@
 
 package com.azavea.hiveless.serializers
 
+import com.azavea.hiveless.serializers.syntax._
 import com.azavea.hiveless.spark.encoders.syntax._
+
 import org.apache.spark.sql.catalyst.encoders.ExpressionEncoder
 import org.apache.spark.sql.types._
 import org.apache.spark.unsafe.types.UTF8String
@@ -106,6 +108,6 @@ object HSerializer extends Serializable {
 
   implicit def arraySerializer[T: HSerializer: ClassTag: λ[τ => C[τ] => Seq[τ]], C[_]]: HSerializer[C[T]] = new HSerializer[C[T]] {
     def dataType: DataType     = ArrayType(HSerializer[T].dataType)
-    def serialize: C[T] => Any = seq => ArrayData.toArrayData(seq.toArray)
+    def serialize: C[T] => Any = seq => ArrayData.toArrayData(seq.map(_.serialize).toArray)
   }
 }

spatial/src/test/scala/com/azavea/hiveless/serializers/GroupString.scala

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2022 Azavea
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.azavea.hiveless.serializers
+
+import com.azavea.hiveless.HUDF
+
+class GroupString extends HUDF[(String, Int), Array[String]] {
+  def function = { case (str, size) => str.grouped(size).toArray }
+}

spatial/src/test/scala/com/azavea/hiveless/serializers/HSerializerSpec.scala

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2022 Azavea
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.azavea.hiveless.serializers
+
+import com.azavea.hiveless.{SpatialHiveTestEnvironment, SpatialTestTables}
+import org.apache.spark.sql.SparkSession
+import org.scalatest.funspec.AnyFunSpec
+
+class HSerializerSpec extends AnyFunSpec with SpatialHiveTestEnvironment with SpatialTestTables {
+  override def registerHiveUDFs(ssc: SparkSession): Unit = {
+    super.registerHiveUDFs(ssc)
+    ssc.sql("CREATE OR REPLACE FUNCTION groupString as 'com.azavea.hiveless.serializers.GroupString';")
+  }
+
+  describe("HSerializerSpec") {
+    it("should correctly serialize arrays of strings") {
+      val (str, n) = ("HSerializerSpecString", 3)
+      val expected = str.grouped(n).toArray
+      val df       = ssc.sql(s"SELECT groupString('$str', $n);".stripMargin)
+
+      df.collect().head.getAs[Array[String]](0) shouldBe expected
+    }
+  }
+}