diff --git a/test/built-ins/isFinite/S15.1.2.5_A1_T1.js b/test/built-ins/isFinite/S15.1.2.5_A1_T1.js
deleted file mode 100644
index c818bd15463dcfee747e1969559f6d018ee5d3aa..0000000000000000000000000000000000000000
--- a/test/built-ins/isFinite/S15.1.2.5_A1_T1.js
+++ /dev/null
@@ -1,70 +0,0 @@
-// Copyright 2009 the Sputnik authors.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: >
-    isFinite applies ToNumber to its argument, then return false if the
-    result is NaN, +Infinity, -Infinity, and otherwise return true
-es5id: 15.1.2.5_A1_T1
-description: Checking all primitive
----*/
-
-// CHECK#1
-if (!(isFinite(NaN) === false)) {
-  $ERROR('#1: NaN === Not-a-Finite. Actual: ' + (NaN)); 
-}
-
-// CHECK#2
-if (!(isFinite(Number.NaN) === false)) {
-  $ERROR('#2: Number.NaN === Not-a-Finite. Actual: ' + (Number.NaN)); 
-}
-
-// CHECK#3
-if (!(isFinite(Number(void 0)) === false)) {
-  $ERROR('#3: Number(void 0) === Not-a-Finite. Actual: ' + (Number(void 0))); 
-}
-
-// CHECK#4
-if (!(isFinite(void 0) === false)) {
-  $ERROR('#4: void 0 === Not-a-Finite. Actual: ' + (void 0)); 
-}
-
-// CHECK#5
-if (!(isFinite("string") === false)) {
-  $ERROR('#5: "string" === Not-a-Finite. Actual: ' + ("string")); 
-}
-
-// CHECK#6
-if (isFinite(Number.POSITIVE_INFINITY) !== false) {
-  $ERROR('#6: Number.POSITIVE_INFINITY === Not-a-Finite. Actual: ' + (Number.POSITIVE_INFINITY)); 
-}
-
-// CHECK#7
-if (isFinite(Number.NEGATIVE_INFINITY) !== false) {
-  $ERROR('#7: Number.NEGATIVE_INFINITY === Not-a-Finite. Actual: ' + (Number.NEGATIVE_INFINITY)); 
-}
-
-// CHECK#8
-if (isFinite(Number.MAX_VALUE) === false) {
-  $ERROR('#8: Number.MAX_VALUE !== Not-a-Finite'); 
-}
-
-// CHECK#9
-if (isFinite(Number.MIN_VALUE) === false) {
-  $ERROR('#9: Number.MIN_VALUE !== Not-a-Finite'); 
-}
-
-// CHECK#10
-if (isFinite(-0) === false) {
-  $ERROR('#10: -0 !== Not-a-Finite'); 
-}
-
-// CHECK#11
-if (isFinite(false) === false) {
-  $ERROR('#11: false !== Not-a-Finite'); 
-}
-
-// CHECK#12
-if (isFinite("1") === false) {
-  $ERROR('#12: "1" !== Not-a-Finite'); 
-}
diff --git a/test/built-ins/isFinite/S15.1.2.5_A1_T2.js b/test/built-ins/isFinite/S15.1.2.5_A1_T2.js
deleted file mode 100644
index 607ad89aaea8982e3ed9f98d989647e88c93e049..0000000000000000000000000000000000000000
--- a/test/built-ins/isFinite/S15.1.2.5_A1_T2.js
+++ /dev/null
@@ -1,40 +0,0 @@
-// Copyright 2009 the Sputnik authors.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: >
-    isFinite applies ToNumber to its argument, then return false if the
-    result is NaN, +Infinity, -Infinity, and otherwise return true
-es5id: 15.1.2.5_A1_T2
-description: Checking all object
----*/
-
-// CHECK#1
-if (!(isFinite({}) === false)) {
-  $ERROR('#1: {} === Not-a-Finite. Actual: ' + ({})); 
-}
-
-// CHECK#2
-if (!(isFinite(new String("string")) === false)) {
-  $ERROR('#2: new String("string") === Not-a-Finite. Actual: ' + (new String("string"))); 
-}
-
-// CHECK#3
-if (isFinite(new String("1")) === false) {
-  $ERROR('#3: new String("1") === Not-a-Finite. Actual: ' + (new String("1"))); 
-}
-
-// CHECK#4
-if (isFinite(new Number(1)) === false) {
-  $ERROR('#4: new Number(1) !== Not-a-Finite'); 
-}
-
-// CHECK#5
-if (!(isFinite(new Number(NaN)) === false)) {
-  $ERROR('#5: new Number(NaN) === Not-a-Finite. Actual: ' + (new Number(NaN))); 
-}
-
-// CHECK#6
-if (isFinite(new Boolean(true)) === false) {
-  $ERROR('#6: new Boolean(true) !== Not-a-Finite'); 
-}
diff --git a/test/built-ins/isFinite/S15.1.2.5_A2.1.js b/test/built-ins/isFinite/S15.1.2.5_A2.1.js
deleted file mode 100644
index a409f4ebb57a67ddcd44e25107641a22f5f53915..0000000000000000000000000000000000000000
--- a/test/built-ins/isFinite/S15.1.2.5_A2.1.js
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2009 the Sputnik authors.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: The length property of isFinite has the attribute DontEnum
-es5id: 15.1.2.5_A2.1
-description: Checking use propertyIsEnumerable, for-in
----*/
-
-//CHECK#1
-if (isFinite.propertyIsEnumerable('length') !== false) {
-  $ERROR('#1: isFinite.propertyIsEnumerable(\'length\') === false. Actual: ' + (isFinite.propertyIsEnumerable('length')));
-}
-
-//CHECK#2
-var result = true;
-for (var p in isFinite){
-  if (p === "length") {
-    result = false;
-  }  
-}
-
-if (result !== true) {
-  $ERROR('#2: result = true; for (p in isFinite) { if (p === "length") result = false; }  result === true;');
-}
diff --git a/test/built-ins/isFinite/S15.1.2.5_A2.2.js b/test/built-ins/isFinite/S15.1.2.5_A2.2.js
deleted file mode 100644
index b1336218973e34b41d08009aa13b5acff62755e8..0000000000000000000000000000000000000000
--- a/test/built-ins/isFinite/S15.1.2.5_A2.2.js
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2009 the Sputnik authors.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: The length property of isFinite does not have the attribute DontDelete
-es5id: 15.1.2.5_A2.2
-description: Checking use hasOwnProperty, delete
----*/
-
-//CHECK#1
-if (isFinite.hasOwnProperty('length') !== true) {
-  $ERROR('#1: isFinite.hasOwnProperty(\'length\') === true. Actual: ' + (isFinite.hasOwnProperty('length')));
-}
-
-delete isFinite.length;
-
-//CHECK#2
-if (isFinite.hasOwnProperty('length') !== false) {
-  $ERROR('#2: delete isFinite.length; isFinite.hasOwnProperty(\'length\') === false. Actual: ' + (isFinite.hasOwnProperty('length')));
-}
-
-//CHECK#3
-if (isFinite.length === undefined) {
-  $ERROR('#3: delete isFinite.length; isFinite.length !== undefined');
-}
diff --git a/test/built-ins/isFinite/S15.1.2.5_A2.3.js b/test/built-ins/isFinite/S15.1.2.5_A2.3.js
deleted file mode 100644
index ea89d94a389a32ccb2c71af27d99fd78f2a6d12e..0000000000000000000000000000000000000000
--- a/test/built-ins/isFinite/S15.1.2.5_A2.3.js
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright 2009 the Sputnik authors.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: The length property of isFinite has the attribute ReadOnly
-es5id: 15.1.2.5_A2.3
-description: Checking if varying the length property fails
-includes: [propertyHelper.js]
----*/
-
-//CHECK#1
-var x = isFinite.length;
-verifyNotWritable(isFinite, "length", null, Infinity);
-if (isFinite.length !== x) {
-  $ERROR('#1: x = isFinite.length; isFinite.length = Infinity; isFinite.length === x. Actual: ' + (isFinite.length));
-}
diff --git a/test/built-ins/isFinite/S15.1.2.5_A2.4.js b/test/built-ins/isFinite/S15.1.2.5_A2.4.js
deleted file mode 100644
index 6af10f2a1fe0501f0dfaee755077e1311575d385..0000000000000000000000000000000000000000
--- a/test/built-ins/isFinite/S15.1.2.5_A2.4.js
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright 2009 the Sputnik authors.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: The length property of isFinite is 1
-es5id: 15.1.2.5_A2.4
-description: isFinite.length === 1
----*/
-
-//CHECK#1
-if (isFinite.length !== 1) {
-  $ERROR('#1: isFinite.length === 1. Actual: ' + (isFinite.length));
-}
diff --git a/test/built-ins/isFinite/S15.1.2.5_A2.5.js b/test/built-ins/isFinite/S15.1.2.5_A2.5.js
deleted file mode 100644
index 42057474c91ef7f5542b376a18edaf48956c8764..0000000000000000000000000000000000000000
--- a/test/built-ins/isFinite/S15.1.2.5_A2.5.js
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2009 the Sputnik authors.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: The isFinite property has the attribute DontEnum
-es5id: 15.1.2.5_A2.5
-description: Checking use propertyIsEnumerable, for-in
----*/
-
-//CHECK#1
-if (this.propertyIsEnumerable('isFinite') !== false) {
-  $ERROR('#1: this.propertyIsEnumerable(\'isFinite\') === false. Actual: ' + (this.propertyIsEnumerable('isFinite')));
-}
-
-//CHECK#2
-var result = true;
-for (var p in this){
-  if (p === "isFinite") {
-    result = false;
-  }  
-}
-
-if (result !== true) {
-  $ERROR('#2: result = true; for (p in this) { if (p === "isFinite") result = false; }  result === true;');
-}
diff --git a/test/built-ins/isFinite/S15.1.2.5_A2.6.js b/test/built-ins/isFinite/S15.1.2.5_A2.6.js
index 71011f1dfe075e7c0c92b671a6a1b211552312ac..5a0e9406d9f1aff31da2ae85699250fe9de7c7ff 100644
--- a/test/built-ins/isFinite/S15.1.2.5_A2.6.js
+++ b/test/built-ins/isFinite/S15.1.2.5_A2.6.js
@@ -4,7 +4,7 @@
 /*---
 info: The isFinite property has not prototype property
 es5id: 15.1.2.5_A2.6
-description: Checking isFinit.prototype
+description: Checking isFinite.prototype
 ---*/
 
 //CHECK#1
diff --git a/test/built-ins/isFinite/length.js b/test/built-ins/isFinite/length.js
new file mode 100644
index 0000000000000000000000000000000000000000..136fdb19f9aae393a391a6c83ee8878fc9af9dc9
--- /dev/null
+++ b/test/built-ins/isFinite/length.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  The length property of isFinite is 1
+includes: [propertyHelper.js]
+---*/
+
+assert.sameValue(isFinite.length, 1, "The value of `isFinite.length` is `1`");
+
+verifyNotEnumerable(isFinite, "length");
+verifyNotWritable(isFinite, "length");
+verifyConfigurable(isFinite, "length");
diff --git a/test/built-ins/isFinite/prop-desc.js b/test/built-ins/isFinite/prop-desc.js
new file mode 100644
index 0000000000000000000000000000000000000000..0147bcddc44d55774227339c4dfe447e8f22d2ad
--- /dev/null
+++ b/test/built-ins/isFinite/prop-desc.js
@@ -0,0 +1,14 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Property descriptor for isFinite
+includes: [propertyHelper.js]
+---*/
+
+verifyNotEnumerable(this, "isFinite");
+verifyWritable(this, "isFinite");
+verifyConfigurable(this, "isFinite");
diff --git a/test/built-ins/isFinite/return-abrupt-from-tonumber-number-symbol.js b/test/built-ins/isFinite/return-abrupt-from-tonumber-number-symbol.js
new file mode 100644
index 0000000000000000000000000000000000000000..1dd19b2bb1dc40b5f928a028e5adb078c4da76bc
--- /dev/null
+++ b/test/built-ins/isFinite/return-abrupt-from-tonumber-number-symbol.js
@@ -0,0 +1,20 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Throws a TypeError if number is a Symbol
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+features: [Symbol]
+---*/
+
+var s = Symbol(1);
+
+assert.throws(TypeError, function() {
+  isFinite(s);
+});
diff --git a/test/built-ins/isFinite/return-abrupt-from-tonumber-number.js b/test/built-ins/isFinite/return-abrupt-from-tonumber-number.js
new file mode 100644
index 0000000000000000000000000000000000000000..afeba7d311d1ebe6b36efc040bd9a0633f8af7ce
--- /dev/null
+++ b/test/built-ins/isFinite/return-abrupt-from-tonumber-number.js
@@ -0,0 +1,33 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Return abrupt completion from ToNumber(number)
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+---*/
+
+var obj1 = {
+  valueOf: function() {
+    throw new Test262Error();
+  }
+};
+
+var obj2 = {
+  toString: function() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, function() {
+  isFinite(obj1);
+}, "valueOf");
+
+assert.throws(Test262Error, function() {
+  isFinite(obj2);
+}, "toString");
diff --git a/test/built-ins/isFinite/return-false-on-nan-or-infinities.js b/test/built-ins/isFinite/return-false-on-nan-or-infinities.js
new file mode 100644
index 0000000000000000000000000000000000000000..c07cf19dff3dac6a2b28dd0d530cb68ee29f814e
--- /dev/null
+++ b/test/built-ins/isFinite/return-false-on-nan-or-infinities.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Return false if number is NaN, Infinity or -Infinity
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+  2. If num is NaN, +∞, or -∞, return false.
+---*/
+
+assert.sameValue(isFinite(NaN), false, "NaN");
+assert.sameValue(isFinite(Infinity), false, "Infinity");
+assert.sameValue(isFinite(-Infinity), false, "-Infinity");
diff --git a/test/built-ins/isFinite/return-true-for-valid-finite-numbers.js b/test/built-ins/isFinite/return-true-for-valid-finite-numbers.js
new file mode 100644
index 0000000000000000000000000000000000000000..9e7eb8165c5e9972d83651dd1b88ef425e51f3d7
--- /dev/null
+++ b/test/built-ins/isFinite/return-true-for-valid-finite-numbers.js
@@ -0,0 +1,26 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Return true if number is not NaN, Infinity or -Infinity
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+  2. If num is NaN, +∞, or -∞, return false.
+  3. Otherwise, return true.
+---*/
+
+assert.sameValue(isFinite(0), true, "0");
+assert.sameValue(isFinite(-0), true, "-0");
+assert.sameValue(isFinite(Math.pow(2, 53)), true, "Math.pow(2, 53)");
+assert.sameValue(isFinite(-Math.pow(2, 53)), true, "-Math.pow(2, 53)");
+assert.sameValue(isFinite(1), true, "1");
+assert.sameValue(isFinite(-1), true, "-1");
+assert.sameValue(isFinite(0.000001), true, "0.000001");
+assert.sameValue(isFinite(-0.000001), true, "-0.000001");
+assert.sameValue(isFinite(1e42), true, "1e42");
+assert.sameValue(isFinite(-1e42), true, "-1e42");
diff --git a/test/built-ins/isFinite/tonumber-operations.js b/test/built-ins/isFinite/tonumber-operations.js
new file mode 100644
index 0000000000000000000000000000000000000000..0048b65e7e520e621f87a7350bf9331858f86fc2
--- /dev/null
+++ b/test/built-ins/isFinite/tonumber-operations.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  number argument is converted by ToNumber
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+  2. If num is NaN, +∞, or -∞, return false.
+  3. Otherwise, return true.
+---*/
+
+assert.sameValue(isFinite("0"), true, "'0'");
+assert.sameValue(isFinite(""), true, "the empty string");
+assert.sameValue(isFinite("Infinity"), false, "'Infinity'");
+assert.sameValue(isFinite("this is not a number"), false, "string");
+assert.sameValue(isFinite(true), true, "true");
+assert.sameValue(isFinite(false), true, "false");
+assert.sameValue(isFinite([1]), true, "Object [1]");
+assert.sameValue(isFinite([Infinity]), false, "Object [Infinity]");
+assert.sameValue(isFinite([NaN]), false, "Object [NaN]");
+assert.sameValue(isFinite(null), true, "null");
+assert.sameValue(isFinite(undefined), false, "undefined");
+assert.sameValue(isFinite(), false, "no arg");
diff --git a/test/built-ins/isFinite/toprimitive-call-abrupt.js b/test/built-ins/isFinite/toprimitive-call-abrupt.js
new file mode 100644
index 0000000000000000000000000000000000000000..9a4242c343be64afe4fc31cf95ec3cfd5ffd3773
--- /dev/null
+++ b/test/built-ins/isFinite/toprimitive-call-abrupt.js
@@ -0,0 +1,30 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Return abrupt completion calling number.@@toPrimitive
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+
+  ToPrimitive ( input [ , PreferredType ] )
+
+  [...]
+  4. Let exoticToPrim be ? GetMethod(input, @@toPrimitive).
+  5. If exoticToPrim is not undefined, then
+    a. Let result be ? Call(exoticToPrim, input, « hint »).
+features: [Symbol.toPrimitive]
+---*/
+
+var obj = {};
+obj[Symbol.toPrimitive] = function() {
+  throw new Test262Error();
+};
+
+assert.throws(Test262Error, function() {
+  isFinite(obj);
+});
diff --git a/test/built-ins/isFinite/toprimitive-get-abrupt.js b/test/built-ins/isFinite/toprimitive-get-abrupt.js
new file mode 100644
index 0000000000000000000000000000000000000000..bc6d05700f558a80d989ad807bd3883f71d5f5c6
--- /dev/null
+++ b/test/built-ins/isFinite/toprimitive-get-abrupt.js
@@ -0,0 +1,29 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Return abrupt completion getting number.@@toPrimitive
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+
+  ToPrimitive ( input [ , PreferredType ] )
+
+  [...]
+  4. Let exoticToPrim be ? GetMethod(input, @@toPrimitive).
+features: [Symbol.toPrimitive]
+---*/
+
+var obj = Object.defineProperty({}, Symbol.toPrimitive, {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  isFinite(obj);
+});
diff --git a/test/built-ins/isFinite/toprimitive-not-callable-throws.js b/test/built-ins/isFinite/toprimitive-not-callable-throws.js
new file mode 100644
index 0000000000000000000000000000000000000000..8ce8703ce83051eea1d7b2b06f48432c5a4bc11c
--- /dev/null
+++ b/test/built-ins/isFinite/toprimitive-not-callable-throws.js
@@ -0,0 +1,53 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Throws a TypeError if number.@@toPrimitive is not null, undefined, or callable
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+
+  ToPrimitive ( input [ , PreferredType ] )
+
+  [...]
+  4. Let exoticToPrim be ? GetMethod(input, @@toPrimitive).
+
+  GetMethod (V, P)
+
+  [...]
+  2. Let func be ? GetV(V, P).
+  3. If func is either undefined or null, return undefined.
+  4. If IsCallable(func) is false, throw a TypeError exception.
+features: [Symbol.toPrimitive]
+---*/
+
+var obj = {};
+
+obj[Symbol.toPrimitive] = 42;
+assert.throws(TypeError, function() {
+  isFinite(obj);
+}, "number");
+
+obj[Symbol.toPrimitive] = "";
+assert.throws(TypeError, function() {
+  isFinite(obj);
+}, "string");
+
+obj[Symbol.toPrimitive] = true;
+assert.throws(TypeError, function() {
+  isFinite(obj);
+}, "boolean");
+
+obj[Symbol.toPrimitive] = Symbol.toPrimitive;
+assert.throws(TypeError, function() {
+  isFinite(obj);
+}, "symbol");
+
+obj[Symbol.toPrimitive] = {};
+assert.throws(TypeError, function() {
+  isFinite(obj);
+}, "object");
diff --git a/test/built-ins/isFinite/toprimitive-result-is-object-throws.js b/test/built-ins/isFinite/toprimitive-result-is-object-throws.js
new file mode 100644
index 0000000000000000000000000000000000000000..017089d9e4eb5c51472f67d69ab2b99a5a3da40d
--- /dev/null
+++ b/test/built-ins/isFinite/toprimitive-result-is-object-throws.js
@@ -0,0 +1,32 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Throws a TypeError if the result of calling number.@@toPrimitive is an Object
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+
+  ToPrimitive ( input [ , PreferredType ] )
+
+  [...]
+  4. Let exoticToPrim be ? GetMethod(input, @@toPrimitive).
+  5. If exoticToPrim is not undefined, then
+    a. Let result be ? Call(exoticToPrim, input, « hint »).
+    b. If Type(result) is not Object, return result.
+    c. Throw a TypeError exception.
+features: [Symbol.toPrimitive]
+---*/
+
+var obj = {};
+obj[Symbol.toPrimitive] = function() {
+  return [42];
+};
+
+assert.throws(TypeError, function() {
+  isFinite(obj);
+});
diff --git a/test/built-ins/isFinite/toprimitive-result-is-symbol-throws.js b/test/built-ins/isFinite/toprimitive-result-is-symbol-throws.js
new file mode 100644
index 0000000000000000000000000000000000000000..0dfa8275df8fdbd44a54096d20f3b3d53486d2e4
--- /dev/null
+++ b/test/built-ins/isFinite/toprimitive-result-is-symbol-throws.js
@@ -0,0 +1,36 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Throws a TypeError if the result of calling number.@@toPrimitive is a symbol
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+
+  ToNumber ( argument )
+
+  1. Let primValue be ? ToPrimitive(argument, hint Number).
+  2. Return ? ToNumber(primValue).
+
+  ToPrimitive ( input [ , PreferredType ] )
+
+  [...]
+  4. Let exoticToPrim be ? GetMethod(input, @@toPrimitive).
+  5. If exoticToPrim is not undefined, then
+    a. Let result be ? Call(exoticToPrim, input, « hint »).
+    b. If Type(result) is not Object, return result.
+features: [Symbol.toPrimitive]
+---*/
+
+var obj = {};
+obj[Symbol.toPrimitive] = function() {
+  return Symbol.toPrimitive;
+};
+
+assert.throws(TypeError, function() {
+  isFinite(obj);
+});
diff --git a/test/built-ins/isFinite/toprimitive-valid-result.js b/test/built-ins/isFinite/toprimitive-valid-result.js
new file mode 100644
index 0000000000000000000000000000000000000000..6af51b57012615a1a652bf82b17f0dc31e65d07e
--- /dev/null
+++ b/test/built-ins/isFinite/toprimitive-valid-result.js
@@ -0,0 +1,81 @@
+// Copyright (C) 2016 The V8 Project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-isfinite-number
+es6id: 18.2.2
+description: >
+  Use non-object value returned from @@toPrimitive method
+info: |
+  isFinite (number)
+
+  1. Let num be ? ToNumber(number).
+
+  ToPrimitive ( input [ , PreferredType ] )
+
+  [...]
+  4. Let exoticToPrim be ? GetMethod(input, @@toPrimitive).
+  5. If exoticToPrim is not undefined, then
+    a. Let result be ? Call(exoticToPrim, input, « hint »).
+    b. If Type(result) is not Object, return result.
+features: [Symbol.toPrimitive]
+---*/
+
+var called = 0;
+var obj = {
+  valueOf: function() {
+    called = NaN;
+    return Infinity;
+  },
+  toString: function() {
+    called = NaN;
+    return Infinity;
+  }
+};
+
+obj[Symbol.toPrimitive] = function() {
+  called += 1;
+  return 42;
+};
+assert.sameValue(isFinite(obj), true, "use returned value - number");
+assert.sameValue(called, 1, "toPrimitive is called - number");
+
+called = 0;
+obj[Symbol.toPrimitive] = function() {
+  called += 1;
+  return "42";
+};
+assert.sameValue(isFinite(obj), true, "use returned value - string");
+assert.sameValue(called, 1, "toPrimitive is called - string");
+
+called = 0;
+obj[Symbol.toPrimitive] = function() {
+  called += 1;
+  return true;
+};
+assert.sameValue(isFinite(obj), true, "use returned value - boolean true");
+assert.sameValue(called, 1, "toPrimitive is called - boolean true");
+
+called = 0;
+obj[Symbol.toPrimitive] = function() {
+  called += 1;
+  return false;
+};
+assert.sameValue(isFinite(obj), true, "use returned value - boolean false");
+assert.sameValue(called, 1, "toPrimitive is called - boolean false");
+
+called = 0;
+obj[Symbol.toPrimitive] = function() {
+  called += 1;
+  return Infinity;
+};
+assert.sameValue(isFinite(obj), false, "use returned value - Infinity");
+assert.sameValue(called, 1, "toPrimitive is called - Infinity");
+
+called = 0;
+obj[Symbol.toPrimitive] = function() {
+  called += 1;
+  return -Infinity;
+};
+assert.sameValue(isFinite(obj), false, "use returned value - -Infinity");
+assert.sameValue(called, 1, "toPrimitive is called - -Infinity");