1 files changed, 70 insertions, 0 deletions
diff --git a/packages/order-utils/test/order_validation_utils_test.ts b/packages/order-utils/test/order_validation_utils_test.ts
new file mode 100644
index 000000000..d3ff867d7
--- /dev/null
+++ b/packages/order-utils/test/order_validation_utils_test.ts
@@ -0,0 +1,70 @@
+import { BigNumber } from '@0xproject/utils';
+import * as chai from 'chai';
+import 'mocha';
+
+import { OrderValidationUtils } from '../src/order_validation_utils';
+
+import { chaiSetup } from './utils/chai_setup';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+describe('OrderValidationUtils', () => {
+    describe('#isRoundingError', () => {
+        it('should return false if there is a rounding error of 0.1%', async () => {
+            const numerator = new BigNumber(20);
+            const denominator = new BigNumber(999);
+            const target = new BigNumber(50);
+            // rounding error = ((20*50/999) - floor(20*50/999)) / (20*50/999) = 0.1%
+            const isRoundingError = OrderValidationUtils.isRoundingError(numerator, denominator, target);
+            expect(isRoundingError).to.be.false();
+        });
+
+        it('should return false if there is a rounding of 0.09%', async () => {
+            const numerator = new BigNumber(20);
+            const denominator = new BigNumber(9991);
+            const target = new BigNumber(500);
+            // rounding error = ((20*500/9991) - floor(20*500/9991)) / (20*500/9991) = 0.09%
+            const isRoundingError = OrderValidationUtils.isRoundingError(numerator, denominator, target);
+            expect(isRoundingError).to.be.false();
+        });
+
+        it('should return true if there is a rounding error of 0.11%', async () => {
+            const numerator = new BigNumber(20);
+            const denominator = new BigNumber(9989);
+            const target = new BigNumber(500);
+            // rounding error = ((20*500/9989) - floor(20*500/9989)) / (20*500/9989) = 0.011%
+            const isRoundingError = OrderValidationUtils.isRoundingError(numerator, denominator, target);
+            expect(isRoundingError).to.be.true();
+        });
+
+        it('should return true if there is a rounding error > 0.1%', async () => {
+            const numerator = new BigNumber(3);
+            const denominator = new BigNumber(7);
+            const target = new BigNumber(10);
+            // rounding error = ((3*10/7) - floor(3*10/7)) / (3*10/7) = 6.67%
+            const isRoundingError = OrderValidationUtils.isRoundingError(numerator, denominator, target);
+            expect(isRoundingError).to.be.true();
+        });
+
+        it('should return false when there is no rounding error', async () => {
+            const numerator = new BigNumber(1);
+            const denominator = new BigNumber(2);
+            const target = new BigNumber(10);
+
+            const isRoundingError = OrderValidationUtils.isRoundingError(numerator, denominator, target);
+            expect(isRoundingError).to.be.false();
+        });
+
+        it('should return false when there is rounding error <= 0.1%', async () => {
+            // randomly generated numbers
+            const numerator = new BigNumber(76564);
+            const denominator = new BigNumber(676373677);
+            const target = new BigNumber(105762562);
+            // rounding error = ((76564*105762562/676373677) - floor(76564*105762562/676373677)) /
+            // (76564*105762562/676373677) = 0.0007%
+            const isRoundingError = OrderValidationUtils.isRoundingError(numerator, denominator, target);
+            expect(isRoundingError).to.be.false();
+        });
+    });
+});