Add generic type coercion utility functions

harness/typeCoercion.js

@@ -0,0 +1,224 @@
+// Copyright (C) 2017 Josh Wolfe. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: |
+    Functions to help generate test cases for testing type coercion abstract
+    operations like ToNumber.
+---*/
+
+function testCoercibleToIntegerZero(test) {
+  function testPrimitiveValue(value) {
+    test(value);
+    // ToPrimitive
+    testPrimitiveWrappers(value, "number", test);
+  }
+
+  // ToNumber
+  testPrimitiveValue(null);
+  testPrimitiveValue(false);
+  testPrimitiveValue(0);
+  testPrimitiveValue("0");
+
+  // ToInteger: NaN -> +0
+  testPrimitiveValue(undefined);
+  testPrimitiveValue(NaN);
+  testPrimitiveValue("");
+  testPrimitiveValue("foo");
+  testPrimitiveValue("true");
+
+  // ToInteger: floor(abs(number))
+  testPrimitiveValue(0.9);
+  testPrimitiveValue(-0);
+  testPrimitiveValue(-0.9);
+  testPrimitiveValue("0.9");
+  testPrimitiveValue("-0");
+  testPrimitiveValue("-0.9");
+
+  // Non-primitive values that coerce to 0:
+  // toString() returns a string that parses to NaN.
+  test({});
+  test([]);
+}
+
+function testCoercibleToIntegerOne(test) {
+  function testPrimitiveValue(value) {
+    test(value);
+    // ToPrimitive
+    testPrimitiveWrappers(value, "number", test);
+  }
+
+  // ToNumber
+  testPrimitiveValue(true);
+  testPrimitiveValue(1);
+  testPrimitiveValue("1");
+
+  // ToInteger: floor(abs(number))
+  testPrimitiveValue(1.9);
+  testPrimitiveValue("1.9");
+
+  // Non-primitive values that coerce to 1:
+  // toString() returns a string that parses to 1.
+  test([1]);
+  test(["1"]);
+}
+
+function testCoercibleToIntegerFromInteger(nominalInteger, test) {
+  assert(Number.isInteger(nominalInteger));
+
+  function testPrimitiveValue(value) {
+    test(value);
+    // ToPrimitive
+    testPrimitiveWrappers(value, "number", test);
+
+    // Non-primitive values that coerce to the nominal integer:
+    // toString() returns a string that parsers to a primitive value.
+    test([value]);
+  }
+
+  function testPrimitiveNumber(number) {
+    testPrimitiveValue(number);
+    // ToNumber: String -> Number
+    testPrimitiveValue(number.toString());
+  }
+
+  testPrimitiveNumber(nominalInteger);
+
+  // ToInteger: floor(abs(number))
+  if (nominalInteger >= 0) {
+    testPrimitiveNumber(nominalInteger + 0.9);
+  }
+  if (nominalInteger <= 0) {
+    testPrimitiveNumber(nominalInteger - 0.9);
+  }
+}
+
+function testPrimitiveWrappers(primitiveValue, hint, test) {
+  if (primitiveValue != null) {
+    // null and undefined result in {} rather than a proper wrapper,
+    // so skip this case for those values.
+    test(Object(primitiveValue));
+  }
+
+  testCoercibleToPrimitiveWithMethod(hint, function() {
+    return primitiveValue;
+  }, test);
+}
+
+function testCoercibleToPrimitiveWithMethod(hint, method, test) {
+  var methodNames;
+  if (hint === "number") {
+    methodNames = ["valueOf", "toString"];
+  } else if (hint === "string") {
+    methodNames = ["toString", "valueOf"];
+  } else {
+    throw new Test262Error();
+  }
+  // precedence order
+  test({
+    [Symbol.toPrimitive]: method,
+    [methodNames[0]]: function() { throw new Test262Error(); },
+    [methodNames[1]]: function() { throw new Test262Error(); },
+  });
+  test({
+    [methodNames[0]]: method,
+    [methodNames[1]]: function() { throw new Test262Error(); },
+  });
+  test({
+    [methodNames[1]]: method,
+  });
+
+  // GetMethod: if func is undefined or null, return undefined.
+  test({
+    [Symbol.toPrimitive]: undefined,
+    [methodNames[0]]: method,
+    [methodNames[1]]: method,
+  });
+  test({
+    [Symbol.toPrimitive]: null,
+    [methodNames[0]]: method,
+    [methodNames[1]]: method,
+  });
+
+  // if methodNames[0] is not callable, fallback to methodNames[1]
+  test({
+    [methodNames[0]]: null,
+    [methodNames[1]]: method,
+  });
+  test({
+    [methodNames[0]]: 1,
+    [methodNames[1]]: method,
+  });
+  test({
+    [methodNames[0]]: {},
+    [methodNames[1]]: method,
+  });
+
+  // if methodNames[0] returns an object, fallback to methodNames[1]
+  test({
+    [methodNames[0]]: function() { return {}; },
+    [methodNames[1]]: method,
+  });
+  test({
+    [methodNames[0]]: function() { return Object(1); },
+    [methodNames[1]]: method,
+  });
+}
+
+function testNotCoercibleToInteger(test) {
+  // ToInteger only throws from ToNumber.
+  return testNotCoercibleToNumber(test);
+}
+function testNotCoercibleToNumber(test) {
+  function testPrimitiveValue(value) {
+    test(TypeError, value);
+    // ToPrimitive
+    testPrimitiveWrappers(value, "number", function(value) {
+      test(TypeError, value);
+    });
+  }
+
+  // ToNumber: Symbol -> TypeError
+  testPrimitiveValue(Symbol("1"));
+
+  if (typeof BigInt !== "undefined") {
+    // ToNumber: BigInt -> TypeError
+    testPrimitiveValue(BigInt(0));
+  }
+
+  // ToPrimitive
+  testNotCoercibleToPrimitive("number", test);
+}
+
+function testNotCoercibleToPrimitive(hint, test) {
+  function MyError() {}
+
+  // ToPrimitive: input[@@toPrimitive] is not callable (and non-null)
+  test(TypeError, {[Symbol.toPrimitive]: 1});
+  test(TypeError, {[Symbol.toPrimitive]: {}});
+
+  // ToPrimitive: input[@@toPrimitive] returns object
+  test(TypeError, {[Symbol.toPrimitive]: function() { return Object(1); }});
+  test(TypeError, {[Symbol.toPrimitive]: function() { return {}; }});
+
+  // ToPrimitive: input[@@toPrimitive] throws
+  test(MyError, {[Symbol.toPrimitive]: function() { throw new MyError(); }});
+
+  // OrdinaryToPrimitive: method throws
+  testCoercibleToPrimitiveWithMethod(hint, function() {
+    throw new MyError();
+  }, function(value) {
+    test(MyError, value);
+  });
+
+  // OrdinaryToPrimitive: both methods are unsuitable
+  function testUnsuitableMethod(method) {
+    test(TypeError, {valueOf:method, toString:method});
+  }
+  // not callable:
+  testUnsuitableMethod(null);
+  testUnsuitableMethod(1);
+  testUnsuitableMethod({});
+  // returns object:
+  testUnsuitableMethod(function() { return Object(1); });
+  testUnsuitableMethod(function() { return {}; });
+}

test/built-ins/String/prototype/indexOf/position-tointeger.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2017 Josh Wolfe. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.indexof
+description: String.prototype.indexOf type coercion for position parameter
+info: >
+  String.prototype.indexOf ( searchString [ , position ] )
+
+  4. Let pos be ? ToInteger(position).
+
+includes: [typeCoercion.js]
+---*/
+
+testCoercibleToIntegerZero(function(zero) {
+  assert.sameValue("aaaa".indexOf("aa", zero), 0);
+});
+
+testCoercibleToIntegerOne(function(one) {
+  assert.sameValue("aaaa".indexOf("aa", one), 1);
+});
+
+testCoercibleToIntegerFromInteger(2, function(two) {
+  assert.sameValue("aaaa".indexOf("aa", two), 2);
+});
+
+testNotCoercibleToInteger(function(error, value) {
+  assert.throws(error, function() { "".indexOf("", value); });
+});