1 files changed, 63 insertions, 0 deletions
diff --git a/packages/contracts/src/utils/assertions.ts b/packages/contracts/src/utils/assertions.ts
new file mode 100644
index 000000000..615e648f3
--- /dev/null
+++ b/packages/contracts/src/utils/assertions.ts
@@ -0,0 +1,63 @@
+import * as chai from 'chai';
+import * as _ from 'lodash';
+
+import { constants } from './constants';
+
+const expect = chai.expect;
+
+function _expectEitherErrorAsync<T>(p: Promise<T>, error1: string, error2: string): PromiseLike<void> {
+    return expect(p)
+        .to.be.rejected()
+        .then(e => {
+            expect(e).to.satisfy(
+                (err: Error) => _.includes(err.message, error1) || _.includes(err.message, error2),
+                `expected promise to reject with error message that includes "${error1}" or "${error2}", but got: ` +
+                    `"${e.message}"\n`,
+            );
+        });
+}
+
+/**
+ * Rejects if the given Promise does not reject with an error indicating
+ * insufficient funds.
+ * @param p the Promise which is expected to reject
+ * @returns a new Promise which will reject if the conditions are not met and
+ * otherwise resolve with no value.
+ */
+export function expectInsufficientFundsAsync<T>(p: Promise<T>): PromiseLike<void> {
+    return _expectEitherErrorAsync(p, 'insufficient funds', "sender doesn't have enough funds");
+}
+
+/**
+ * Rejects if the given Promise does not reject with a "revert" error or the
+ * given otherError.
+ * @param p the Promise which is expected to reject
+ * @param otherError the other error which is accepted as a valid reject error.
+ * @returns a new Promise which will reject if the conditions are not met and
+ * otherwise resolve with no value.
+ */
+export function expectRevertOrOtherErrorAsync<T>(p: Promise<T>, otherError: string): PromiseLike<void> {
+    return _expectEitherErrorAsync(p, constants.REVERT, otherError);
+}
+
+/**
+ * Rejects if the given Promise does not reject with a "revert" or "always
+ * failing transaction" error.
+ * @param p the Promise which is expected to reject
+ * @returns a new Promise which will reject if the conditions are not met and
+ * otherwise resolve with no value.
+ */
+export function expectRevertOrAlwaysFailingTransactionAsync<T>(p: Promise<T>): PromiseLike<void> {
+    return expectRevertOrOtherErrorAsync(p, 'always failing transaction');
+}
+
+/**
+ * Rejects if the given Promise does not reject with a "revert" or "Contract
+ * call failed" error.
+ * @param p the Promise which is expected to reject
+ * @returns a new Promise which will reject if the conditions are not met and
+ * otherwise resolve with no value.
+ */
+export function expectRevertOrContractCallFailedAsync<T>(p: Promise<T>): PromiseLike<void> {
+    return expectRevertOrOtherErrorAsync<T>(p, 'Contract call failed');
+}