test more edge-cases on empty values on insert

src/main/kotlin/jako/dsl/insert/Insert.kt

@@ -7,14 +7,14 @@ import java.sql.Date
 import java.time.LocalDate
 
 class Insert: StatementBuilder() {
-    private var insertInto: InsertInto? = null
+    private var insertInto: InsertInto = InsertInto("")
     private var insertRow: InsertRow = InsertRow()
     private var returning: Returning = Returning()
 
     override fun blocks() = listOf(insertIntoOrThrow(), rowOrThrow(), returning)
 
     fun into(table: String): Insert {
-        this.insertInto = InsertInto(table)
+        insertInto = InsertInto(table)
         return this
     }
 
@@ -39,7 +39,7 @@ class Insert: StatementBuilder() {
     }
 
     private fun rowOrThrow() = if (insertRow.isPresent()) insertRow else throw RuntimeException("Cannot generate insert without values")
-    private fun insertIntoOrThrow() = insertInto ?: throw RuntimeException("Cannot generate insert without table name")
+    private fun insertIntoOrThrow() = if (insertInto.isPresent()) insertInto else throw RuntimeException("Cannot generate insert without table name")
 
     companion object {
         fun into(table: String): Insert {

src/main/kotlin/jako/dsl/insert/InsertRow.kt

@@ -11,11 +11,13 @@ internal class InsertRow: StatementBlock {
         return this
     }
 
-    override fun toSQL(dialect: Dialect) = if(cols.isNotEmpty()) "(${columnNames(dialect)}) VALUES (${placeholders()})" else ""
-    override fun params(): List<Any?> = cols.map { it.value }
-    override fun isPresent() = cols.any { it.isPresent() }
+    override fun toSQL(dialect: Dialect) = "(${columnNames(dialect)}) VALUES (${placeholders()})"
+    override fun params(): List<Any?> = presentCols().map { it.value }
+    override fun isPresent() = presentCols().isNotEmpty()
 
-    private fun columnNames(dialect: Dialect) = cols.joinToString(prefix = "${dialect.columnSeparator}", separator = "${dialect.columnSeparator}, ${dialect.columnSeparator}", postfix = "${dialect.columnSeparator}") { it.name }
+    private fun columnNames(dialect: Dialect) = presentCols().joinToString(prefix = dialect.columnSeparator, separator = "${dialect.columnSeparator}, ${dialect.columnSeparator}", postfix = dialect.columnSeparator) { it.name }
 
-    private fun placeholders() = List(cols.size) { "?" }.joinToString(", ")
+    private fun placeholders() = List(presentCols().size) { "?" }.joinToString(", ")
+
+    private fun presentCols() = cols.filter { it.isPresent() }
 }

src/test/kotlin/jako/dsl/insert/InsertTest.kt

@@ -18,6 +18,23 @@ class InsertTest {
         assertEquals(listOf("1", 2, "3"), insert.params())
     }
 
+    @Test
+    fun `insert into EMPTY param`() {
+        val insert = Insert.into("table").set("", "0").set("col1", "1")
+
+        assertEquals("INSERT INTO \"table\" (\"col1\") VALUES (?)", insert.toSQL(PSQL))
+        assertEquals(listOf("1"), insert.params())
+    }
+
+    @Test
+    fun `insert into with empty table`() {
+        val message = assertThrows(RuntimeException::class.java) {
+            Insert.into("").set("col1", "1").toSQL(PSQL)
+        }.message
+
+        assertThat(message).isEqualTo("Cannot generate insert without table name")
+    }
+
     @Test
     fun `insert without values`() {
         val message = assertThrows(RuntimeException::class.java) {