src/jvm/src/main/kotlin/extensions/Connection.kt

@@ -56,6 +56,7 @@ fun <TDoc> Connection.customSingle(
  * @throws DocumentException If parameters are invalid
  */
 @Throws(DocumentException::class)
+@JvmOverloads
 fun Connection.customNonQuery(query: String, parameters: Collection<Parameter<*>> = listOf()) =
     Custom.nonQuery(query, parameters, this)
 

src/jvm/src/main/kotlin/jvm/Results.kt

@@ -40,9 +40,8 @@ object Results {
      * @param mapFunc The mapping function from data reader to domain class instance
      * @param clazz The class of the document to be returned
      * @return A list of items from the query's result
-     * @throws DocumentException If there is a problem executing the query
+     * @throws DocumentException If there is a problem executing the query (unchecked)
      */
-    @Throws(DocumentException::class)
     @JvmStatic
     fun <TDoc> toCustomList(
         stmt: PreparedStatement, clazz: Class<TDoc>, mapFunc: (ResultSet, Class<TDoc>) -> TDoc
@@ -65,9 +64,8 @@ object Results {
      * @param rs A `ResultSet` set to the row with the count to retrieve
      * @param clazz The type parameter (ignored; this always returns `Long`)
      * @return The count from the row
-     * @throws DocumentException If the dialect has not been set
+     * @throws DocumentException If the dialect has not been set (unchecked)
      */
-    @Throws(DocumentException::class)
     @JvmStatic
     fun toCount(rs: ResultSet, clazz: Class<*>) =
         when (Configuration.dialect()) {
@@ -81,9 +79,8 @@ object Results {
      * @param rs A `ResultSet` set to the row with the true/false value to retrieve
      * @param clazz The type parameter (ignored; this always returns `Boolean`)
      * @return The true/false value from the row
-     * @throws DocumentException If the dialect has not been set
+     * @throws DocumentException If the dialect has not been set (unchecked)
      */
-    @Throws(DocumentException::class)
     @JvmStatic
     fun toExists(rs: ResultSet, clazz: Class<*>) =
         when (Configuration.dialect()) {

src/jvm/src/test/groovy/solutions/bitbadger/documents/groovy/jvm/integration/common/CustomFunctions.groovy

@@ -0,0 +1,72 @@
+package solutions.bitbadger.documents.groovy.jvm.integration.common
+
+import solutions.bitbadger.documents.Configuration
+import solutions.bitbadger.documents.Field
+import solutions.bitbadger.documents.Parameter
+import solutions.bitbadger.documents.ParameterType
+import solutions.bitbadger.documents.groovy.support.JsonDocument
+import solutions.bitbadger.documents.jvm.Results
+import solutions.bitbadger.documents.query.CountQuery
+import solutions.bitbadger.documents.query.DeleteQuery
+import solutions.bitbadger.documents.query.FindQuery
+import solutions.bitbadger.documents.support.ThrowawayDatabase
+
+import static org.junit.jupiter.api.Assertions.*
+import static solutions.bitbadger.documents.extensions.ConnExt.*
+import static solutions.bitbadger.documents.support.TypesKt.TEST_TABLE
+
+class CustomFunctions {
+
+    static void listEmpty(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        deleteByFields(db.conn, TEST_TABLE, List.of(Field.exists(Configuration.idField)))
+        def result = customList(db.conn, FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results.&fromData)
+        assertEquals(0, result.size(), "There should have been no results")
+    }
+
+    static void listAll(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        def result = customList(db.conn, FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results.&fromData)
+        assertEquals(5, result.size(), "There should have been 5 results")
+    }
+
+    static void singleNone(ThrowawayDatabase db) {
+        assertNull(customSingle(db.conn, FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results.&fromData),
+                "There should not have been a document returned")
+
+    }
+
+    static void singleOne(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertNotNull(
+                customSingle(db.conn, FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results.&fromData),
+                "There should not have been a document returned")
+    }
+
+    static void nonQueryChanges(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(5L, customScalar(db.conn, CountQuery.all(TEST_TABLE), List.of(), Long.class, Results.&toCount),
+                "There should have been 5 documents in the table")
+        customNonQuery(db.conn, "DELETE FROM $TEST_TABLE")
+        assertEquals(0L, customScalar(db.conn, CountQuery.all(TEST_TABLE), List.of(), Long.class, Results.&toCount),
+                "There should have been no documents in the table")
+    }
+
+    static void nonQueryNoChanges(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(5L, customScalar(db.conn, CountQuery.all(TEST_TABLE), List.of(), Long.class, Results.&toCount),
+                "There should have been 5 documents in the table")
+        customNonQuery(db.conn, DeleteQuery.byId(TEST_TABLE, "eighty-two"),
+                List.of(new Parameter(":id", ParameterType.STRING, "eighty-two")))
+        assertEquals(5L, customScalar(db.conn, CountQuery.all(TEST_TABLE), List.of(), Long.class, Results.&toCount),
+                "There should still have been 5 documents in the table")
+    }
+
+    static void scalar(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(3L,
+                customScalar(db.conn, "SELECT 3 AS it FROM $TEST_TABLE LIMIT 1", List.of(), Long.class,
+                        Results.&toCount),
+                "The number 3 should have been returned")
+    }
+}

src/jvm/src/test/groovy/solutions/bitbadger/documents/groovy/jvm/integration/postgresql/CountIT.groovy

@@ -14,42 +14,42 @@ class CountIT {
     @Test
     @DisplayName("all counts all documents")
     void all() {
-        new PgDB().withCloseable { CountFunctions.all(it) }
+        new PgDB().withCloseable(CountFunctions.&all)
     }
 
     @Test
     @DisplayName("byFields counts documents by a numeric value")
     void byFieldsNumeric() {
-        new PgDB().withCloseable { CountFunctions.byFieldsNumeric(it) }
+        new PgDB().withCloseable(CountFunctions.&byFieldsNumeric)
     }
 
     @Test
     @DisplayName("byFields counts documents by a alphanumeric value")
     void byFieldsAlpha() {
-        new PgDB().withCloseable { CountFunctions.byFieldsAlpha(it) }
+        new PgDB().withCloseable(CountFunctions.&byFieldsAlpha)
     }
 
     @Test
     @DisplayName("byContains counts documents when matches are found")
     void byContainsMatch() {
-        new PgDB().withCloseable { CountFunctions.byContainsMatch(it) }
+        new PgDB().withCloseable(CountFunctions.&byContainsMatch)
     }
 
     @Test
     @DisplayName("byContains counts documents when no matches are found")
     void byContainsNoMatch() {
-        new PgDB().withCloseable { CountFunctions.byContainsNoMatch(it) }
+        new PgDB().withCloseable(CountFunctions.&byContainsNoMatch)
     }
 
     @Test
     @DisplayName("byJsonPath counts documents when matches are found")
     void byJsonPathMatch() {
-        new PgDB().withCloseable { CountFunctions.byJsonPathMatch(it) }
+        new PgDB().withCloseable(CountFunctions.&byJsonPathMatch)
     }
 
     @Test
     @DisplayName("byJsonPath counts documents when no matches are found")
     void byJsonPathNoMatch() {
-        new PgDB().withCloseable { CountFunctions.byJsonPathNoMatch(it) }
+        new PgDB().withCloseable(CountFunctions.&byJsonPathNoMatch)
     }
 }

src/jvm/src/test/groovy/solutions/bitbadger/documents/groovy/jvm/integration/postgresql/CustomIT.groovy

@@ -0,0 +1,55 @@
+package solutions.bitbadger.documents.groovy.jvm.integration.postgresql
+
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+import solutions.bitbadger.documents.groovy.jvm.integration.common.CustomFunctions
+import solutions.bitbadger.documents.jvm.integration.postgresql.PgDB
+
+/**
+ * PostgreSQL integration tests for the `Custom` object / `custom*` connection extension functions
+ */
+@DisplayName("JVM | Groovy | PostgreSQL: Custom")
+class CustomIT {
+
+    @Test
+    @DisplayName("list succeeds with empty list")
+    void listEmpty() {
+        new PgDB().withCloseable(CustomFunctions.&listEmpty)
+    }
+
+    @Test
+    @DisplayName("list succeeds with a non-empty list")
+    void listAll() {
+        new PgDB().withCloseable(CustomFunctions.&listAll)
+    }
+
+    @Test
+    @DisplayName("single succeeds when document not found")
+    void singleNone() {
+        new PgDB().withCloseable(CustomFunctions.&singleNone)
+    }
+
+    @Test
+    @DisplayName("single succeeds when a document is found")
+    void singleOne() {
+        new PgDB().withCloseable(CustomFunctions.&singleOne)
+    }
+
+    @Test
+    @DisplayName("nonQuery makes changes")
+    void nonQueryChanges() {
+        new PgDB().withCloseable(CustomFunctions.&nonQueryChanges)
+    }
+
+    @Test
+    @DisplayName("nonQuery makes no changes when where clause matches nothing")
+    void nonQueryNoChanges() {
+        new PgDB().withCloseable(CustomFunctions.&nonQueryNoChanges)
+    }
+
+    @Test
+    @DisplayName("scalar succeeds")
+    void scalar() {
+        new PgDB().withCloseable(CustomFunctions.&scalar)
+    }
+}

src/jvm/src/test/groovy/solutions/bitbadger/documents/groovy/jvm/integration/sqlite/CustomIT.groovy

@@ -0,0 +1,55 @@
+package solutions.bitbadger.documents.groovy.jvm.integration.sqlite
+
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+import solutions.bitbadger.documents.groovy.jvm.integration.common.CustomFunctions
+import solutions.bitbadger.documents.jvm.integration.sqlite.SQLiteDB
+
+/**
+ * SQLite integration tests for the `Custom` object / `custom*` connection extension functions
+ */
+@DisplayName("JVM | Groovy | SQLite: Custom")
+class CustomIT {
+
+    @Test
+    @DisplayName("list succeeds with empty list")
+    void listEmpty() {
+        new SQLiteDB().withCloseable(CustomFunctions.&listEmpty)
+    }
+
+    @Test
+    @DisplayName("list succeeds with a non-empty list")
+    void listAll() {
+        new SQLiteDB().withCloseable(CustomFunctions.&listAll)
+    }
+
+    @Test
+    @DisplayName("single succeeds when document not found")
+    void singleNone() {
+        new SQLiteDB().withCloseable(CustomFunctions.&singleNone)
+    }
+
+    @Test
+    @DisplayName("single succeeds when a document is found")
+    void singleOne() {
+        new SQLiteDB().withCloseable(CustomFunctions.&singleOne)
+    }
+
+    @Test
+    @DisplayName("nonQuery makes changes")
+    void nonQueryChanges() {
+        new SQLiteDB().withCloseable(CustomFunctions.&nonQueryChanges)
+    }
+
+    @Test
+    @DisplayName("nonQuery makes no changes when where clause matches nothing")
+    void nonQueryNoChanges() {
+        new SQLiteDB().withCloseable(CustomFunctions.&nonQueryNoChanges)
+    }
+
+    @Test
+    @DisplayName("scalar succeeds")
+    void scalar() {
+        new SQLiteDB().withCloseable(CustomFunctions.&scalar)
+    }
+}

src/jvm/src/test/groovy/solutions/bitbadger/documents/groovy/support/JsonDocument.groovy

@@ -11,7 +11,7 @@ class JsonDocument {
     int numValue
     SubDocument sub
 
-    JsonDocument(String id, String value = "", int numValue = 0, SubDocument sub = null) {
+    JsonDocument(String id = null, String value = "", int numValue = 0, SubDocument sub = null) {
         this.id = id
         this.value = value
         this.numValue = numValue

src/jvm/src/test/groovy/solutions/bitbadger/documents/groovy/support/SubDocument.groovy

@@ -4,7 +4,7 @@ class SubDocument {
     String foo
     String bar
 
-    SubDocument(String foo, String bar) {
+    SubDocument(String foo = "", String bar = "") {
         this.foo = foo
         this.bar = bar
     }

src/jvm/src/test/java/solutions/bitbadger/documents/java/jvm/integration/common/CustomFunctions.java

@@ -0,0 +1,78 @@
+package solutions.bitbadger.documents.java.jvm.integration.common;
+
+import solutions.bitbadger.documents.*;
+import solutions.bitbadger.documents.java.support.JsonDocument;
+import solutions.bitbadger.documents.jvm.Results;
+import solutions.bitbadger.documents.query.CountQuery;
+import solutions.bitbadger.documents.query.DeleteQuery;
+import solutions.bitbadger.documents.query.FindQuery;
+import solutions.bitbadger.documents.support.ThrowawayDatabase;
+
+import java.util.Collection;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static solutions.bitbadger.documents.extensions.ConnExt.*;
+import static solutions.bitbadger.documents.support.TypesKt.TEST_TABLE;
+
+final public class CustomFunctions {
+
+    public static void listEmpty(ThrowawayDatabase db) throws DocumentException {
+        JsonDocument.load(db);
+        deleteByFields(db.getConn(), TEST_TABLE, List.of(Field.exists(Configuration.idField)));
+        Collection<JsonDocument> result =
+                customList(db.getConn(), FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results::fromData);
+        assertEquals(0, result.size(), "There should have been no results");
+    }
+
+    public static void listAll(ThrowawayDatabase db) throws DocumentException {
+        JsonDocument.load(db);
+        Collection<JsonDocument> result =
+                customList(db.getConn(), FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results::fromData);
+        assertEquals(5, result.size(), "There should have been 5 results");
+    }
+
+    public static void singleNone(ThrowawayDatabase db) throws DocumentException {
+        assertNull(
+                customSingle(db.getConn(), FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results::fromData),
+                "There should not have been a document returned");
+    }
+
+    public static void singleOne(ThrowawayDatabase db) throws DocumentException {
+        JsonDocument.load(db);
+        assertNotNull(
+                customSingle(db.getConn(), FindQuery.all(TEST_TABLE), List.of(), JsonDocument.class, Results::fromData),
+                "There should not have been a document returned");
+    }
+
+    public static void nonQueryChanges(ThrowawayDatabase db) throws DocumentException {
+        JsonDocument.load(db);
+        assertEquals(5L,
+                customScalar(db.getConn(), CountQuery.all(TEST_TABLE), List.of(), Long.class, Results::toCount),
+                "There should have been 5 documents in the table");
+        customNonQuery(db.getConn(), String.format("DELETE FROM %s", TEST_TABLE));
+        assertEquals(0L,
+                customScalar(db.getConn(), CountQuery.all(TEST_TABLE), List.of(), Long.class, Results::toCount),
+                "There should have been no documents in the table");
+    }
+
+    public static void nonQueryNoChanges(ThrowawayDatabase db) throws DocumentException {
+        JsonDocument.load(db);
+        assertEquals(5L,
+                customScalar(db.getConn(), CountQuery.all(TEST_TABLE), List.of(), Long.class, Results::toCount),
+                "There should have been 5 documents in the table");
+        customNonQuery(db.getConn(), DeleteQuery.byId(TEST_TABLE, "eighty-two"),
+                List.of(new Parameter<>(":id", ParameterType.STRING, "eighty-two")));
+        assertEquals(5L,
+                customScalar(db.getConn(), CountQuery.all(TEST_TABLE), List.of(), Long.class, Results::toCount),
+                "There should still have been 5 documents in the table");
+    }
+
+    public static void scalar(ThrowawayDatabase db) throws DocumentException {
+        JsonDocument.load(db);
+        assertEquals(3L,
+                customScalar(db.getConn(), String.format("SELECT 3 AS it FROM %s LIMIT 1", TEST_TABLE), List.of(),
+                        Long.class, Results::toCount),
+                "The number 3 should have been returned");
+    }
+}

src/jvm/src/test/java/solutions/bitbadger/documents/java/jvm/integration/postgresql/CustomIT.java

@@ -0,0 +1,70 @@
+package solutions.bitbadger.documents.java.jvm.integration.postgresql;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import solutions.bitbadger.documents.DocumentException;
+import solutions.bitbadger.documents.jvm.integration.postgresql.PgDB;
+import solutions.bitbadger.documents.java.jvm.integration.common.CustomFunctions;
+
+/**
+ * PostgreSQL integration tests for the `Custom` object / `custom*` connection extension functions
+ */
+@DisplayName("JVM | Java | PostgreSQL: Custom")
+final public class CustomIT {
+
+    @Test
+    @DisplayName("list succeeds with empty list")
+    public void listEmpty() throws DocumentException {
+        try (PgDB db = new PgDB()) {
+            CustomFunctions.listEmpty(db);
+        }
+    }
+
+    @Test
+    @DisplayName("list succeeds with a non-empty list")
+    public void listAll() throws DocumentException {
+        try (PgDB db = new PgDB()) {
+            CustomFunctions.listAll(db);
+        }
+    }
+
+    @Test
+    @DisplayName("single succeeds when document not found")
+    public void singleNone() throws DocumentException {
+        try (PgDB db = new PgDB()) {
+            CustomFunctions.singleNone(db);
+        }
+    }
+
+    @Test
+    @DisplayName("single succeeds when a document is found")
+    public void singleOne() throws DocumentException {
+        try (PgDB db = new PgDB()) {
+            CustomFunctions.singleOne(db);
+        }
+    }
+
+    @Test
+    @DisplayName("nonQuery makes changes")
+    public void nonQueryChanges() throws DocumentException {
+        try (PgDB db = new PgDB()) {
+            CustomFunctions.nonQueryChanges(db);
+        }
+    }
+
+    @Test
+    @DisplayName("nonQuery makes no changes when where clause matches nothing")
+    public void nonQueryNoChanges() throws DocumentException {
+        try (PgDB db = new PgDB()) {
+            CustomFunctions.nonQueryNoChanges(db);
+        }
+    }
+
+    @Test
+    @DisplayName("scalar succeeds")
+    public void scalar() throws DocumentException {
+        try (PgDB db = new PgDB()) {
+            CustomFunctions.scalar(db);
+        }
+    }
+}

src/jvm/src/test/java/solutions/bitbadger/documents/java/jvm/integration/sqlite/CustomIT.java

@@ -0,0 +1,70 @@
+package solutions.bitbadger.documents.java.jvm.integration.sqlite;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import solutions.bitbadger.documents.DocumentException;
+import solutions.bitbadger.documents.java.jvm.integration.common.CustomFunctions;
+import solutions.bitbadger.documents.jvm.integration.sqlite.SQLiteDB;
+
+/**
+ * SQLite integration tests for the `Custom` object / `custom*` connection extension functions
+ */
+@DisplayName("JVM | Java | SQLite: Custom")
+final public class CustomIT {
+
+    @Test
+    @DisplayName("list succeeds with empty list")
+    public void listEmpty() throws DocumentException {
+        try (SQLiteDB db = new SQLiteDB()) {
+            CustomFunctions.listEmpty(db);
+        }
+    }
+
+    @Test
+    @DisplayName("list succeeds with a non-empty list")
+    public void listAll() throws DocumentException {
+        try (SQLiteDB db = new SQLiteDB()) {
+            CustomFunctions.listAll(db);
+        }
+    }
+
+    @Test
+    @DisplayName("single succeeds when document not found")
+    public void singleNone() throws DocumentException {
+        try (SQLiteDB db = new SQLiteDB()) {
+            CustomFunctions.singleNone(db);
+        }
+    }
+
+    @Test
+    @DisplayName("single succeeds when a document is found")
+    public void singleOne() throws DocumentException {
+        try (SQLiteDB db = new SQLiteDB()) {
+            CustomFunctions.singleOne(db);
+        }
+    }
+
+    @Test
+    @DisplayName("nonQuery makes changes")
+    public void nonQueryChanges() throws DocumentException {
+        try (SQLiteDB db = new SQLiteDB()) {
+            CustomFunctions.nonQueryChanges(db);
+        }
+    }
+
+    @Test
+    @DisplayName("nonQuery makes no changes when where clause matches nothing")
+    public void nonQueryNoChanges() throws DocumentException {
+        try (SQLiteDB db = new SQLiteDB()) {
+            CustomFunctions.nonQueryNoChanges(db);
+        }
+    }
+
+    @Test
+    @DisplayName("scalar succeeds")
+    public void scalar() throws DocumentException {
+        try (SQLiteDB db = new SQLiteDB()) {
+            CustomFunctions.scalar(db);
+        }
+    }
+}

src/jvm/src/test/java/solutions/bitbadger/documents/java/support/JsonDocument.java

@@ -62,6 +62,10 @@ public class JsonDocument {
     public JsonDocument(String id) {
         this(id, "", 0, null);
     }
+    
+    public JsonDocument() {
+        this(null);
+    }
 
     private static final List<JsonDocument> testDocuments = List.of(
             new JsonDocument("one", "FIRST!", 0),

src/jvm/src/test/kotlin/jvm/integration/postgresql/CustomIT.kt

@@ -8,7 +8,7 @@ import kotlin.test.Test
 /**
  * PostgreSQL integration tests for the `Custom` object / `custom*` connection extension functions
  */
-@DisplayName("Java | Kotlin | PostgreSQL: Custom")
+@DisplayName("JVM | Kotlin | PostgreSQL: Custom")
 class CustomIT {
 
     @Test

src/jvm/src/test/kotlin/jvm/integration/sqlite/CustomIT.kt

@@ -7,7 +7,7 @@ import kotlin.test.Test
 /**
  * SQLite integration tests for the `Custom` object / `custom*` connection extension functions
  */
-@DisplayName("Java | Kotlin | SQLite: Custom")
+@DisplayName("JVM | Kotlin | SQLite: Custom")
 class CustomIT {
 
     @Test

src/jvm/src/test/scala/solutions/bitbadger/documents/scala/jvm/integration/common/CustomFunctions.scala

@@ -0,0 +1,75 @@
+package solutions.bitbadger.documents.scala.jvm.integration.common
+
+import org.junit.jupiter.api.Assertions.*
+import solutions.bitbadger.documents.{Configuration, Field, Parameter, ParameterType}
+import solutions.bitbadger.documents.extensions.ConnExt.*
+import solutions.bitbadger.documents.jvm.Results
+import solutions.bitbadger.documents.query.{CountQuery, DeleteQuery, FindQuery}
+import solutions.bitbadger.documents.scala.support.JsonDocument
+import solutions.bitbadger.documents.support.ThrowawayDatabase
+import solutions.bitbadger.documents.support.TypesKt.TEST_TABLE
+
+import scala.annotation.nowarn
+import scala.jdk.CollectionConverters.*
+
+object CustomFunctions {
+
+  def listEmpty(db: ThrowawayDatabase): Unit =
+    JsonDocument.load(db)
+    deleteByFields(db.getConn, TEST_TABLE, (Field.exists(Configuration.idField) :: Nil).asJava)
+    @nowarn
+    val result = customList(db.getConn, FindQuery.all(TEST_TABLE), List().asJava, classOf[JsonDocument],
+      Results.fromData)
+    assertEquals(0, result.size, "There should have been no results")
+
+  def listAll(db: ThrowawayDatabase): Unit =
+    JsonDocument.load(db)
+    @nowarn
+    val result = customList(db.getConn, FindQuery.all(TEST_TABLE), List().asJava, classOf[JsonDocument],
+      Results.fromData)
+    assertEquals(5, result.size, "There should have been 5 results")
+
+  @nowarn
+  def singleNone(db: ThrowawayDatabase): Unit =
+    assertNull(
+      customSingle(db.getConn, FindQuery.all(TEST_TABLE), List().asJava, classOf[JsonDocument], Results.fromData),
+      "There should not have been a document returned")
+
+  @nowarn
+  def singleOne(db: ThrowawayDatabase): Unit =
+    JsonDocument.load(db)
+    assertNotNull(
+      customSingle(db.getConn, FindQuery.all(TEST_TABLE), List().asJava, classOf[JsonDocument], Results.fromData),
+      "There should not have been a document returned")
+
+  @nowarn
+  def nonQueryChanges(db: ThrowawayDatabase): Unit =
+    JsonDocument.load(db)
+    assertEquals(5L,
+      customScalar(db.getConn, CountQuery.all(TEST_TABLE), List().asJava, classOf[Long], Results.toCount),
+      "There should have been 5 documents in the table")
+    customNonQuery(db.getConn, s"DELETE FROM $TEST_TABLE")
+    assertEquals(0L,
+      customScalar(db.getConn, CountQuery.all(TEST_TABLE), List().asJava, classOf[Long], Results.toCount),
+      "There should have been no documents in the table")
+
+  @nowarn
+  def nonQueryNoChanges(db: ThrowawayDatabase): Unit =
+    JsonDocument.load(db)
+    assertEquals(5L,
+      customScalar(db.getConn, CountQuery.all(TEST_TABLE), List().asJava, classOf[Long], Results.toCount),
+      "There should have been 5 documents in the table")
+    customNonQuery(db.getConn, DeleteQuery.byId(TEST_TABLE, "eighty-two"),
+      (Parameter(":id", ParameterType.STRING, "eighty-two") :: Nil).asJava)
+    assertEquals(5L,
+      customScalar(db.getConn, CountQuery.all(TEST_TABLE), List().asJava, classOf[Long], Results.toCount),
+      "There should still have been 5 documents in the table")
+
+  @nowarn
+  def scalar(db: ThrowawayDatabase): Unit =
+    JsonDocument.load(db)
+    assertEquals(3L,
+      customScalar(db.getConn, s"SELECT 3 AS it FROM $TEST_TABLE LIMIT 1", List().asJava, classOf[Long],
+        Results.toCount),
+      "The number 3 should have been returned")
+}

src/jvm/src/test/scala/solutions/bitbadger/documents/scala/jvm/integration/postgresql/CustomIT.scala

@@ -0,0 +1,46 @@
+package solutions.bitbadger.documents.scala.jvm.integration.postgresql
+
+import org.junit.jupiter.api.{DisplayName, Test}
+import solutions.bitbadger.documents.jvm.integration.postgresql.PgDB
+import solutions.bitbadger.documents.scala.jvm.integration.common.CustomFunctions
+
+import scala.util.Using
+
+@DisplayName("JVM | Scala | PostgreSQL: Custom")
+class CustomIT {
+
+  @Test
+  @DisplayName("list succeeds with empty list")
+  def listEmpty(): Unit =
+    Using(PgDB()) { db => CustomFunctions.listEmpty(db) }
+
+  @Test
+  @DisplayName("list succeeds with a non-empty list")
+  def listAll(): Unit =
+    Using(PgDB()) { db => CustomFunctions.listAll(db) }
+
+  @Test
+  @DisplayName("single succeeds when document not found")
+  def singleNone(): Unit =
+    Using(PgDB()) { db => CustomFunctions.singleNone(db) }
+
+  @Test
+  @DisplayName("single succeeds when a document is found")
+  def singleOne(): Unit =
+    Using(PgDB()) { db => CustomFunctions.singleOne(db) }
+
+  @Test
+  @DisplayName("nonQuery makes changes")
+  def nonQueryChanges(): Unit =
+    Using(PgDB()) { db => CustomFunctions.nonQueryChanges(db) }
+
+  @Test
+  @DisplayName("nonQuery makes no changes when where clause matches nothing")
+  def nonQueryNoChanges(): Unit =
+    Using(PgDB()) { db => CustomFunctions.nonQueryNoChanges(db) }
+
+  @Test
+  @DisplayName("scalar succeeds")
+  def scalar(): Unit =
+    Using(PgDB()) { db => CustomFunctions.scalar(db) }
+}

src/jvm/src/test/scala/solutions/bitbadger/documents/scala/jvm/integration/sqlite/CustomIT.scala

@@ -0,0 +1,46 @@
+package solutions.bitbadger.documents.scala.jvm.integration.sqlite
+
+import org.junit.jupiter.api.{DisplayName, Test}
+import solutions.bitbadger.documents.jvm.integration.sqlite.SQLiteDB
+import solutions.bitbadger.documents.scala.jvm.integration.common.CustomFunctions
+
+import scala.util.Using
+
+@DisplayName("JVM | Scala | SQLite: Custom")
+class CustomIT {
+
+  @Test
+  @DisplayName("list succeeds with empty list")
+  def listEmpty(): Unit =
+    Using(SQLiteDB()) { db => CustomFunctions.listEmpty(db) }
+
+  @Test
+  @DisplayName("list succeeds with a non-empty list")
+  def listAll(): Unit =
+    Using(SQLiteDB()) { db => CustomFunctions.listAll(db) }
+
+  @Test
+  @DisplayName("single succeeds when document not found")
+  def singleNone(): Unit =
+    Using(SQLiteDB()) { db => CustomFunctions.singleNone(db) }
+
+  @Test
+  @DisplayName("single succeeds when a document is found")
+  def singleOne(): Unit =
+    Using(SQLiteDB()) { db => CustomFunctions.singleOne(db) }
+
+  @Test
+  @DisplayName("nonQuery makes changes")
+  def nonQueryChanges(): Unit =
+    Using(SQLiteDB()) { db => CustomFunctions.nonQueryChanges(db) }
+
+  @Test
+  @DisplayName("nonQuery makes no changes when where clause matches nothing")
+  def nonQueryNoChanges(): Unit =
+    Using(SQLiteDB()) { db => CustomFunctions.nonQueryNoChanges(db) }
+
+  @Test
+  @DisplayName("scalar succeeds")
+  def scalar(): Unit =
+    Using(SQLiteDB()) { db => CustomFunctions.scalar(db) }
+}