Add support for oneOf assertions

Author: asmarques

chai-bignumber.js

@@ -6,6 +6,7 @@ module.exports = function (BigNumber) {
   var isGreaterThanOrEqualTo = BigNumber.prototype.isGreaterThanOrEqualTo || BigNumber.prototype.greaterThanOrEqualTo;
   var isLessThan = BigNumber.prototype.isLessThan || BigNumber.prototype.lessThan;
   var isLessThanOrEqualTo = BigNumber.prototype.isLessThanOrEqualTo || BigNumber.prototype.lessThanOrEqualTo;
+  var oneOf = BigNumber.prototype.oneOf
 
   return function (chai, utils) {
     chai.Assertion.addProperty('bignumber', function () {
@@ -155,5 +156,29 @@ module.exports = function (BigNumber) {
         value.toString()
       );
     });
+
+    // BigNumber.oneOf
+    chai.Assertion.overwriteMethod('oneOf', function (original) {
+      return function (list) {
+        if (utils.flag(this, 'bignumber')) {
+          var value = convert(this._obj);
+          var found = false
+          for (var i = 0; i < list.length; i++) {
+            if (value.isEqualTo(list[i])) {
+              found = true;
+            }
+          }
+          this.assert(
+            found,
+            'expected #{this} to be one of #{exp}',
+            'expected #{this} to not be one of #{exp}',
+            list
+          )
+        } else {
+          original.apply(this, arguments);
+        }
+      };
+    });
+
   };
 };

test/chai-bignumber.test.js

@@ -723,4 +723,38 @@ describe('chai-bignumber', function () {
       }
     });
   });
+
+  describe('oneOf', function () {
+    it('should find number in array', function () {
+      var tests = [
+        [new BigNumber(0), [new BigNumber(0), null, undefined]],
+        [1, [1, new BigNumber(2), 5]],
+        ["3", [new BigNumber(3), 6, 7, "8"]],
+        [new BigNumber(4), [4, "10", new BigNumber(6)]],
+        [new BigNumber(5), ["5", new BigNumber(10)]],
+      ];
+
+      for (var i = 0; i < tests.length; i++) {
+        var a = tests[i][0];
+        var l = tests[i][1];
+        a.should.be.bignumber.oneOf(l);
+        expect(a).to.be.bignumber.oneOf(l);
+      }
+    });
+
+    it('should not find number in array', function () {
+      var tests = [
+        [new BigNumber(0), []],
+        [10, [1, new BigNumber(2), 5]],
+        ["3", [new BigNumber(30), null, undefined]],
+      ];
+
+      for (var i = 0; i < tests.length; i++) {
+        var a = tests[i][0];
+        var l = tests[i][1];
+        a.should.not.be.bignumber.oneOf(l);
+        expect(a).to.not.be.bignumber.oneOf(l);
+      }
+    });
+  });
 });