unit test and improve PostgresArray

src/main/java/net/hostsharing/hsadminng/mapper/PostgresArray.java

@@ -42,7 +42,10 @@ public class PostgresArray {
         tokenizer.remove("\"", "\"");
         final T[] array = newGenericArray(elementClass, tokenizer.getSize()); // Create a new array of the specified type and length
         for ( int n = 0; n < tokenizer.getSize(); ++n ) {
-            array[n] = itemParser.apply(tokenizer.getToken(n).trim().replace("\\\"", "\""));
+            final String token = tokenizer.getToken(n);
+            if ( !"NULL".equals(token) ) {
+                array[n] = itemParser.apply(token.trim().replace("\\\"", "\""));
+            }
         }
         return array;
     }

src/test/java/net/hostsharing/hsadminng/mapper/PostgresArrayIntegrationTest.java

@@ -0,0 +1,88 @@
+package net.hostsharing.hsadminng.mapper;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+
+import jakarta.persistence.EntityManager;
+
+import java.util.UUID;
+import java.util.function.Function;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DataJpaTest
+class PostgresArrayIntegrationTest {
+
+    @Autowired
+    EntityManager em;
+
+    @Test
+    void shouldCreateEmptyArray() {
+        em.createNativeQuery("""            
+            create or replace function returnEmptyArray()
+                returns text[]
+                stable leakproof
+                language plpgsql as $$
+            declare
+                emptyArray text[] = '{}';
+            begin
+                return emptyArray;
+            end; $$;
+            """).executeUpdate();
+        final byte[] pgArray = (byte[]) em.createNativeQuery("SELECT returnEmptyArray()", String[].class).getSingleResult();
+
+        final String[] result = PostgresArray.fromPostgresArray(pgArray, String.class, Function.identity());
+
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void shouldCreateStringArray() {
+        em.createNativeQuery("""            
+            create or replace function returnStringArray()
+                returns varchar(63)[]
+                stable leakproof
+                language plpgsql as $$
+            declare
+                text1 text = 'one';
+                text2 text = 'two, three';
+                text3 text = 'four; five';
+                text4 text = 'say "Hello" to me';
+            begin
+                return array[text1, text2, text3, null, text4];
+            end; $$;
+            """).executeUpdate();
+        final byte[] pgArray = (byte[]) em.createNativeQuery("SELECT returnStringArray()", String[].class).getSingleResult();
+
+        final String[] result = PostgresArray.fromPostgresArray(pgArray, String.class, Function.identity());
+
+        assertThat(result).containsExactly("one", "two, three", "four; five", null, "say \"Hello\" to me");
+    }
+
+    @Test
+    void shouldCreateUUidArray() {
+        em.createNativeQuery("""            
+            create or replace function returnUuidArray()
+                returns uuid[]
+                stable leakproof
+                language plpgsql as $$
+            declare
+                uuid1 UUID = 'f47ac10b-58cc-4372-a567-0e02b2c3d479';
+                uuid2 UUID = '6ba7b810-9dad-11d1-80b4-00c04fd430c8';
+                uuid3 UUID = '01234567-89ab-cdef-0123-456789abcdef';
+            begin
+                return ARRAY[uuid1, uuid2, null, uuid3];
+            end; $$;
+            """).executeUpdate();
+        final byte[] pgArray = (byte[]) em.createNativeQuery("SELECT returnUuidArray()", UUID[].class).getSingleResult();
+
+        final UUID[] result = PostgresArray.fromPostgresArray(pgArray, UUID.class, UUID::fromString);
+
+        assertThat(result).containsExactly(
+                UUID.fromString("f47ac10b-58cc-4372-a567-0e02b2c3d479"),
+                UUID.fromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8"),
+                null,
+                UUID.fromString("01234567-89ab-cdef-0123-456789abcdef"));
+    }
+}