Fixes last conformance test

partiql-eval/src/main/kotlin/org/partiql/eval/internal/helpers/ValueUtility.kt

@@ -59,12 +59,17 @@ internal object ValueUtility {
     }
 
     /**
-     * Takes in a [Datum] that is any integer type ([PartiQLValueType.INT8], [PartiQLValueType.INT8],
-     * [PartiQLValueType.INT8], [PartiQLValueType.INT8], [PartiQLValueType.INT8]) and returns the [BigInteger] (potentially
-     * coerced) that represents the integer.
+     * Converts all number values to [BigInteger]. If the number is [PType.DECIMAL] or [PType.NUMERIC], this asserts that
+     * the scale is zero.
      *
      * INTERNAL NOTE: The PLANNER should be handling the coercion. This function should not be necessary.
      *
+     * TODO: This is used specifically for LIMIT and OFFSET. This makes the conformance tests pass by coercing values
+     *  of type [PType.NUMERIC] and [PType.DECIMAL], but this is unspecified. Do we allow for LIMIT 2.0? Or of
+     *  a value that is greater than [PType.BIGINT]'s MAX value by using a [PType.DECIMAL] with a high precision and scale
+     *  of zero? This hasn't been decided, however, as the conformance tests allow for this, this function coerces
+     *  the value to a [BigInteger] regardless of the number's type.
+     *
      * @throws NullPointerException if the value is null
      * @throws TypeCheckException if type is not an integer type
      */
@@ -75,8 +80,13 @@ internal object ValueUtility {
             PType.SMALLINT -> this.short.toInt().toBigInteger()
             PType.INTEGER -> this.int.toBigInteger()
             PType.BIGINT -> this.long.toBigInteger()
-            PType.NUMERIC -> this.bigDecimal.toBigInteger()
-            PType.DECIMAL -> this.bigDecimal.toBigInteger()
+            PType.NUMERIC, PType.DECIMAL -> {
+                val decimal = this.bigDecimal
+                if (decimal.scale() != 0) {
+                    throw TypeCheckException("Expected integer, but received decimal.")
+                }
+                return decimal.toBigInteger()
+            }
             else -> throw TypeCheckException("Type: ${this.type}")
         }
     }