diff --git a/AlgebraicDataflowArchitectureModel/src/tests/NumberUtilTest.java b/AlgebraicDataflowArchitectureModel/src/tests/NumberUtilTest.java
index 9c47aee..bc12d93 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/NumberUtilTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/NumberUtilTest.java
@@ -36,6 +36,7 @@
 		assertFalse("Underscore immediately after prefix", NumberUtil.isHexNumber("0x_123"));
 		assertFalse("Trailing underscore", NumberUtil.isHexNumber("0x123_"));
 		assertFalse("Trailing underscore with L", NumberUtil.isHexNumber("0x123_L"));
+		assertFalse("Successive underscores", NumberUtil.isHexNumber("0x123__456"));
 		
 		// Long suffix rules
 		assertFalse("L in middle", NumberUtil.isHexNumber("0x1L2"));
@@ -76,6 +77,7 @@
 		assertFalse("Underscore immediately after prefix", NumberUtil.isBinaryNumber("0b_101"));
 		assertFalse("Trailing underscore", NumberUtil.isBinaryNumber("0b101_"));
 		assertFalse("Trailing underscore with L", NumberUtil.isBinaryNumber("0b101_L"));
+		assertFalse("Successive underscores", NumberUtil.isHexNumber("0b101__010"));
 		
 		// Long suffix rules
 		assertFalse("L in middle", NumberUtil.isBinaryNumber("0b1L0"));