--- a/test/nashorn/src/jdk/nashorn/internal/runtime/doubleconv/test/BignumDtoaTest.java	Thu Jul 11 11:36:56 2019 +0100
+++ b/test/nashorn/src/jdk/nashorn/internal/runtime/doubleconv/test/BignumDtoaTest.java	Thu Jul 11 17:11:54 2019 +0200
@@ -69,7 +69,7 @@
 import static org.testng.Assert.assertTrue;
 
 /**
- * FastDtoa tests
+ * BignumDtoa tests
  */
 @SuppressWarnings("javadoc")
 public class BignumDtoaTest {
@@ -220,6 +220,11 @@
         assertEquals(299, buffer.getDecimalPoint());
         buffer.reset();
 
+        DoubleConversion.bignumDtoa(1e-23, DtoaMode.SHORTEST, 0, buffer);
+        assertEquals("1", buffer.getRawDigits());
+        assertEquals(-22, buffer.getDecimalPoint());
+        buffer.reset();
+
         final long smallest_normal64 = 0x0010000000000000L;
         double v = Double.longBitsToDouble(smallest_normal64);
         DoubleConversion.bignumDtoa(v, DtoaMode.SHORTEST, 0, buffer);