Make assertion stricter so that one cannot submit invalid baseUnit amounts to `toUnitAmount`

2 files changed, 7 insertions, 1 deletions

diff --git a/packages/0x.js/src/0x.ts b/packages/0x.js/src/0x.ts
index 7393cc814..596d6ffba 100644
--- a/packages/0x.js/src/0x.ts
+++ b/packages/0x.js/src/0x.ts
@@ -128,7 +128,7 @@ export class ZeroEx {
      * @return  The amount in units.
      */
     public static toUnitAmount(amount: BigNumber, decimals: number): BigNumber {
-        assert.isBigNumber('amount', amount);
+        assert.isValidBaseUnitAmount('amount', amount);
         assert.isNumber('decimals', decimals);
 
         const aUnit = new BigNumber(10).pow(decimals);
diff --git a/packages/0x.js/test/0x.js_test.ts b/packages/0x.js/test/0x.js_test.ts
index 8d62b3518..9bf504909 100644
--- a/packages/0x.js/test/0x.js_test.ts
+++ b/packages/0x.js/test/0x.js_test.ts
@@ -114,6 +114,12 @@ describe('ZeroEx library', () => {
         });
     });
     describe('#toUnitAmount', () => {
+        it('should throw if invalid baseUnit amount supplied as argument', () => {
+            const invalidBaseUnitAmount = new BigNumber(1000000000.4);
+            const decimals = 6;
+            expect(() => ZeroEx.toUnitAmount(invalidBaseUnitAmount, decimals))
+                .to.throw('amount should be in baseUnits (no decimals), found value: 1000000000.4');
+        });
         it('Should return the expected unit amount for the decimals passed in', () => {
             const baseUnitAmount = new BigNumber(1000000000);
             const decimals = 6;