fix: Support Short type for BigDecimal conversion functions (#1746)

* support Short type for BigDecimal conversion functions

- in case of avg aggregate functions for h2 db - it returns Short type and fail convert it to BigDecimal.

* short doesn't have toBigDecimal extension function

* Add unit test for H2 (both v1 and v2)

---------

Co-authored-by: Chantal Loncle <82039410+bog-walk@users.noreply.github.com>

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/ColumnType.kt

@@ -490,6 +490,7 @@ class DecimalColumnType(
         }
         is Long -> value.toBigDecimal()
         is Int -> value.toBigDecimal()
+        is Short -> value.toLong().toBigDecimal()
         else -> error("Unexpected value of type Decimal: $value of ${value::class.qualifiedName}")
     }.setScale(scale, RoundingMode.HALF_EVEN)
 

exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/h2/H2Tests.kt

@@ -91,6 +91,29 @@ class H2Tests : DatabaseTestsBase() {
         }
     }
 
+    @Test
+    fun testH2V1WithBigDecimalFunctionThatReturnsShort() {
+        val testTable = object : Table("test_table") {
+            val number = short("number")
+        }
+
+        withDb(TestDB.allH2TestDB) {
+            try {
+                SchemaUtils.create(testTable)
+
+                testTable.batchInsert(listOf<Short>(2, 4, 6, 8, 10)) { n ->
+                    this[testTable.number] = n
+                }
+
+                val average = testTable.number.avg()
+                val result = testTable.select(average).single()[average]
+                assertEquals("6.00".toBigDecimal(), result)
+            } finally {
+                SchemaUtils.drop(testTable)
+            }
+        }
+    }
+
     class WrappedTransactionManager(val transactionManager: TransactionManager) :
         TransactionManager by transactionManager