[SPARK-32576][SQL][TEST][FOLLOWUP] Add tests for all the character ar…

…ray types in PostgresIntegrationSuite

### What changes were proposed in this pull request?

This is a follow-up PR of #29192 that adds integration tests for character arrays in `PostgresIntegrationSuite`.

### Why are the changes needed?

For better test coverage.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Add tests.

Closes #29397 from maropu/SPARK-32576-FOLLOWUP.

Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>

external/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/PostgresIntegrationSuite.scala

@@ -83,6 +83,13 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite {
     ).executeUpdate()
     conn.prepareStatement("INSERT INTO char_types VALUES " +
       "('abcd', 'efgh', 'ijkl', 'mnop', 'q')").executeUpdate()
+
+    conn.prepareStatement("CREATE TABLE char_array_types (" +
+      "c0 char(4)[], c1 character(4)[], c2 character varying(4)[], c3 varchar(4)[], c4 bpchar[])"
+    ).executeUpdate()
+    conn.prepareStatement("INSERT INTO char_array_types VALUES " +
+      """('{"a", "bcd"}', '{"ef", "gh"}', '{"i", "j", "kl"}', '{"mnop"}', '{"q", "r"}')"""
+    ).executeUpdate()
   }
 
   test("Type mapping for various types") {
@@ -235,4 +242,16 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite {
     assert(row(0).getString(3) === "mnop")
     assert(row(0).getString(4) === "q")
   }
+
+  test("SPARK-32576: character array type tests") {
+    val df = sqlContext.read.jdbc(jdbcUrl, "char_array_types", new Properties)
+    val row = df.collect()
+    assert(row.length == 1)
+    assert(row(0).length === 5)
+    assert(row(0).getSeq[String](0) === Seq("a   ", "bcd "))
+    assert(row(0).getSeq[String](1) === Seq("ef  ", "gh  "))
+    assert(row(0).getSeq[String](2) === Seq("i", "j", "kl"))
+    assert(row(0).getSeq[String](3) === Seq("mnop"))
+    assert(row(0).getSeq[String](4) === Seq("q", "r"))
+  }
 }