[Pisces] / object.test.js

// ♓🌟 Piscēs ∷ object.test.js
// ====================================================================
//
// Copyright © 2022–2023 Lady [@ Lady’s Computer].
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at <https://mozilla.org/MPL/2.0/>.

import {
  assert,
  assertEquals,
  assertSpyCall,
  assertSpyCalls,
  assertStrictEquals,
  assertThrows,
  describe,
  it,
  spy,
} from "./dev-deps.js";
import {
  defineOwnProperties,
  defineOwnProperty,
  deleteOwnProperty,
  freeze,
  frozenCopy,
  getMethod,
  getOwnPropertyDescriptor,
  getOwnPropertyDescriptors,
  getOwnPropertyKeys,
  getOwnPropertyStrings,
  getOwnPropertySymbols,
  getPropertyValue,
  getPrototype,
  hasOwnProperty,
  hasProperty,
  isExtensibleObject,
  isUnfrozenObject,
  isUnsealedObject,
  LazyLoader,
  namedEntries,
  namedKeys,
  namedValues,
  objectCreate,
  objectFromEntries,
  preventExtensions,
  PropertyDescriptor,
  seal,
  setPropertyValue,
  setPropertyValues,
  setPrototype,
  toObject,
  toPropertyKey,
} from "./object.js";

describe("LazyLoader", () => {
  const symbol = Symbol("foo");
  const prototype = {};
  const etaoinMethod = spy(() => "success");
  const shrdluMethod = spy(() => "success");
  const cmfwypMethod = spy(() => "success");
  const vbgkqjMethod = spy(() => "success");
  const methodsObject = Object.create(
    prototype,
    {
      etaoin: {
        configurable: false,
        enumerable: true,
        value: etaoinMethod,
        writable: false,
      },
      shrdlu: {
        configurable: true,
        enumerable: false,
        value: shrdluMethod,
        writable: false,
      },
      cmfwyp: {
        configurable: true,
        enumerable: false,
        get() {
          return cmfwypMethod;
        },
      },
      vbgkqj: {
        configurable: false,
        enumerable: true,
        get() {
          return vbgkqjMethod;
        },
        set(_) {},
      },
      xzfiflffffi: { configurable: true, enumerable: false, set(_) {} },
      [symbol]: {
        configurable: true,
        enumerable: false,
        value: "failure",
        writable: true,
      },
    },
  );

  it("[[Call]] throws an error", () => {
    assertThrows(() => LazyLoader({}));
  });

  it("[[Construct]] creates a new object which inherits from the correct prototype", () => {
    assertStrictEquals(
      Object.getPrototypeOf(new LazyLoader(methodsObject)),
      prototype,
    );
  });

  it("[[Construct]] creates a new object with the desired properties", () => {
    assertEquals(
      Reflect.ownKeys(new LazyLoader(methodsObject)),
      ["etaoin", "shrdlu", "cmfwyp", "vbgkqj", "xzfiflffffi", symbol],
    );
  });

  it("[[Construct]] creates a new object with configurable properties", () => {
    assertEquals(
      Object.fromEntries(
        function* (ll) {
          for (const key of Reflect.ownKeys(ll)) {
            yield [
              key,
              Object.getOwnPropertyDescriptor(ll, key).configurable,
            ];
          }
        }(new LazyLoader(methodsObject)),
      ),
      {
        etaoin: true,
        shrdlu: true,
        cmfwyp: true,
        vbgkqj: true,
        xzfiflffffi: true,
        [symbol]: true,
      },
    );
  });

  it("[[Construct]] creates a new object with the correct enumerability", () => {
    assertEquals(
      Object.fromEntries(
        function* (ll) {
          for (const key of Reflect.ownKeys(ll)) {
            yield [
              key,
              Object.getOwnPropertyDescriptor(ll, key).enumerable,
            ];
          }
        }(new LazyLoader(methodsObject)),
      ),
      {
        etaoin: true,
        shrdlu: false,
        cmfwyp: false,
        vbgkqj: true,
        xzfiflffffi: false,
        [symbol]: false,
      },
    );
  });

  it("[[Construct]] creates a new object with defined getters", () => {
    assertEquals(
      Object.fromEntries(
        function* (ll) {
          for (const key of Reflect.ownKeys(ll)) {
            yield [
              key,
              Object.getOwnPropertyDescriptor(ll, key).get?.name,
            ];
          }
        }(new LazyLoader(methodsObject)),
      ),
      {
        etaoin: "get etaoin",
        shrdlu: "get shrdlu",
        cmfwyp: "get cmfwyp",
        vbgkqj: "get vbgkqj",
        xzfiflffffi: "get xzfiflffffi",
        [symbol]: `get [${symbol.description}]`,
      },
    );
  });

  it("[[Construct]] creates a new object with defined setters for writable properties only", () => {
    assertEquals(
      Object.fromEntries(
        function* (ll) {
          for (const key of Reflect.ownKeys(ll)) {
            yield [
              key,
              Object.getOwnPropertyDescriptor(ll, key).set?.name,
            ];
          }
        }(new LazyLoader(methodsObject)),
      ),
      {
        etaoin: undefined,
        shrdlu: undefined,
        cmfwyp: undefined,
        vbgkqj: undefined,
        xzfiflffffi: undefined,
        [symbol]: `set [${symbol.description}]`,
      },
    );
  });

  it("[[Construct]] creates a new object with correct getter behaviour", () => {
    const ll = new LazyLoader(methodsObject);
    ll.etaoin;
    assertEquals(
      Object.getOwnPropertyDescriptor(ll, "etaoin"),
      {
        configurable: false,
        enumerable: true,
        value: "success",
        writable: false,
      },
    );
    assertSpyCalls(etaoinMethod, 1);
    assertSpyCall(etaoinMethod, 0, {
      args: [],
      self: ll,
      returned: "success",
    });
    ll.shrdlu;
    assertEquals(
      Object.getOwnPropertyDescriptor(ll, "shrdlu"),
      {
        configurable: true,
        enumerable: false,
        value: "success",
        writable: false,
      },
    );
    assertSpyCalls(shrdluMethod, 1);
    assertSpyCall(shrdluMethod, 0, {
      args: [],
      self: ll,
      returned: "success",
    });
    ll.cmfwyp;
    assertEquals(
      Object.getOwnPropertyDescriptor(ll, "cmfwyp"),
      {
        configurable: true,
        enumerable: false,
        value: "success",
        writable: false,
      },
    );
    assertSpyCalls(cmfwypMethod, 1);
    assertSpyCall(cmfwypMethod, 0, {
      args: [],
      self: ll,
      returned: "success",
    });
    ll.vbgkqj;
    assertEquals(
      Object.getOwnPropertyDescriptor(ll, "vbgkqj"),
      {
        configurable: false,
        enumerable: true,
        value: "success",
        writable: false,
      },
    );
    assertSpyCalls(vbgkqjMethod, 1);
    assertSpyCall(vbgkqjMethod, 0, {
      args: [],
      self: ll,
      returned: "success",
    });
    assertThrows(() => ll.xzfiflffffi);
    assertThrows(() => ll[symbol]);
  });

  it("[[Construct]] creates a new object with correct setter behaviour", () => {
    const ll = new LazyLoader(methodsObject);
    ll[symbol] = "success";
    assertEquals(
      Object.getOwnPropertyDescriptor(ll, symbol),
      {
        configurable: true,
        enumerable: false,
        value: "success",
        writable: true,
      },
    );
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(LazyLoader.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(LazyLoader.name, "LazyLoader");
    });
  });
});

describe("PropertyDescriptor", () => {
  it("[[Call]] throws an error", () => {
    assertThrows(() => PropertyDescriptor({}));
  });

  it("[[Construct]] creates a new PropertyDescriptor", () => {
    assertStrictEquals(
      Object.getPrototypeOf(new PropertyDescriptor({})),
      PropertyDescriptor.prototype,
    );
  });

  it("[[Construct]] throws for primitives", () => {
    assertThrows(() => new PropertyDescriptor("failure"));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(PropertyDescriptor.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        PropertyDescriptor.name,
        "PropertyDescriptor",
      );
    });
  });

  describe("::complete", () => {
    it("[[Call]] completes a generic descriptor", () => {
      const desc = {};
      PropertyDescriptor.prototype.complete.call(desc);
      assertEquals(desc, {
        configurable: false,
        enumerable: false,
        value: undefined,
        writable: false,
      });
    });

    it("[[Call]] completes a data descriptor", () => {
      const desc = { value: undefined };
      PropertyDescriptor.prototype.complete.call(desc);
      assertEquals(desc, {
        configurable: false,
        enumerable: false,
        value: undefined,
        writable: false,
      });
    });

    it("[[Call]] completes an accessor descriptor", () => {
      const desc = { get: undefined };
      PropertyDescriptor.prototype.complete.call(desc);
      assertEquals(desc, {
        configurable: false,
        enumerable: false,
        get: undefined,
        set: undefined,
      });
    });

    describe(".length", () => {
      it("[[Get]] returns the correct length", () => {
        assertStrictEquals(
          PropertyDescriptor.prototype.complete.length,
          0,
        );
      });
    });

    describe(".name", () => {
      it("[[Get]] returns the correct name", () => {
        assertStrictEquals(
          PropertyDescriptor.prototype.complete.name,
          "complete",
        );
      });
    });
  });

  describe("::isAccessorDescriptor", () => {
    it("[[Get]] returns false for a generic descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isAccessorDescriptor",
          {},
        ),
        false,
      );
    });

    it("[[Get]] returns false for a data descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isAccessorDescriptor",
          { value: undefined },
        ),
        false,
      );
    });

    it("[[Get]] returns true for an accessor descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isAccessorDescriptor",
          { get: undefined },
        ),
        true,
      );
    });

    describe("[[GetOwnProperty]].get.length", () => {
      it("[[Get]] returns the correct length", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isAccessorDescriptor",
          ).get.length,
          0,
        );
      });
    });

    describe("[[GetOwnProperty]].get.name", () => {
      it("[[Get]] returns the correct name", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isAccessorDescriptor",
          ).get.name,
          "get isAccessorDescriptor",
        );
      });
    });
  });

  describe("::isDataDescriptor", () => {
    it("[[Get]] returns false for a generic descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isDataDescriptor",
          {},
        ),
        false,
      );
    });

    it("[[Get]] returns true for a data descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isDataDescriptor",
          { value: undefined },
        ),
        true,
      );
    });

    it("[[Get]] returns false for an accessor descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isDataDescriptor",
          { get: undefined },
        ),
        false,
      );
    });

    describe("[[GetOwnProperty]].get.length", () => {
      it("[[Get]] returns the correct length", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isDataDescriptor",
          ).get.length,
          0,
        );
      });
    });

    describe("[[GetOwnProperty]].get.name", () => {
      it("[[Get]] returns the correct name", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isDataDescriptor",
          ).get.name,
          "get isDataDescriptor",
        );
      });
    });
  });

  describe("::isFullyPopulated", () => {
    it("[[Get]] returns false for a generic descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isFullyPopulated",
          {},
        ),
        false,
      );
    });

    it("[[Get]] returns false for a non‐fully‐populated data descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isFullyPopulated",
          { value: undefined },
        ),
        false,
      );
    });

    it("[[Get]] returns true for a fully‐populated data descriptor", () => {
      assertStrictEquals(
        Reflect.get(PropertyDescriptor.prototype, "isFullyPopulated", {
          configurable: true,
          enumerable: true,
          value: undefined,
          writable: true,
        }),
        true,
      );
    });

    it("[[Get]] returns false for a non‐fully‐populated accessor descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isFullyPopulated",
          { get: undefined },
        ),
        false,
      );
    });

    it("[[Get]] returns true for a fully‐populated accessor descriptor", () => {
      assertStrictEquals(
        Reflect.get(PropertyDescriptor.prototype, "isFullyPopulated", {
          configurable: true,
          enumerable: true,
          get: undefined,
          set: undefined,
        }),
        true,
      );
    });

    describe("[[GetOwnProperty]].get.length", () => {
      it("[[Get]] returns the correct length", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isFullyPopulated",
          ).get.length,
          0,
        );
      });
    });

    describe("[[GetOwnProperty]].get.name", () => {
      it("[[Get]] returns the correct name", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isFullyPopulated",
          ).get.name,
          "get isFullyPopulated",
        );
      });
    });
  });

  describe("::isGenericDescriptor", () => {
    it("[[Get]] returns true for a generic descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isGenericDescriptor",
          {},
        ),
        true,
      );
    });

    it("[[Get]] returns true for a data descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isGenericDescriptor",
          { value: undefined },
        ),
        false,
      );
    });

    it("[[Get]] returns false for an accessor descriptor", () => {
      assertStrictEquals(
        Reflect.get(
          PropertyDescriptor.prototype,
          "isGenericDescriptor",
          { get: undefined },
        ),
        false,
      );
    });

    describe("[[GetOwnProperty]].get.length", () => {
      it("[[Get]] returns the correct length", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isGenericDescriptor",
          ).get.length,
          0,
        );
      });
    });

    describe("[[GetOwnProperty]].get.name", () => {
      it("[[Get]] returns the correct name", () => {
        assertStrictEquals(
          Object.getOwnPropertyDescriptor(
            PropertyDescriptor.prototype,
            "isGenericDescriptor",
          ).get.name,
          "get isGenericDescriptor",
        );
      });
    });
  });

  describe("~configurable", () => {
    it("[[DefineOwnProperty]] coerces to a boolean", () => {
      const desc = new PropertyDescriptor({});
      Object.defineProperty(desc, "configurable", {});
      assertStrictEquals(desc.configurable, false);
    });

    it("[[DefineOwnProperty]] throws for accessor properties", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() =>
        Object.defineProperty(desc, "configurable", { get: undefined })
      );
    });

    it("[[Set]] coerces to a boolean", () => {
      const desc = new PropertyDescriptor({});
      desc.configurable = undefined;
      assertStrictEquals(desc.configurable, false);
    });

    it("[[Delete]] works", () => {
      const desc = new PropertyDescriptor({ configurable: false });
      delete desc.configurable;
      assert(!("configurable" in desc));
    });
  });

  describe("~enumerable", () => {
    it("[[DefineOwnProperty]] coerces to a boolean", () => {
      const desc = new PropertyDescriptor({});
      Object.defineProperty(desc, "enumerable", {});
      assertStrictEquals(desc.enumerable, false);
    });

    it("[[DefineOwnProperty]] throws for accessor properties", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() =>
        Object.defineProperty(desc, "enumerable", { get: undefined })
      );
    });

    it("[[Set]] coerces to a boolean", () => {
      const desc = new PropertyDescriptor({});
      desc.enumerable = undefined;
      assertStrictEquals(desc.enumerable, false);
    });

    it("[[Delete]] works", () => {
      const desc = new PropertyDescriptor({ enumerable: false });
      delete desc.enumerable;
      assert(!("enumerable" in desc));
    });
  });

  describe("~get", () => {
    it("[[DefineOwnProperty]] works", () => {
      const desc = new PropertyDescriptor({});
      Object.defineProperty(desc, "get", {});
      assertStrictEquals(desc.get, undefined);
    });

    it("[[DefineOwnProperty]] throws for accessor properties", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() =>
        Object.defineProperty(desc, "get", { get: undefined })
      );
    });

    it("[[DefineOwnProperty]] throws if not callable or undefined", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(
        () => Object.defineProperty(desc, "get", { value: null }),
      );
    });

    it("[[DefineOwnProperty]] throws if a data property is defined", () => {
      const desc = new PropertyDescriptor({ value: undefined });
      assertThrows(() => Object.defineProperty(desc, "get", {}));
    });

    it("[[Set]] works", () => {
      const desc = new PropertyDescriptor({});
      const fn = () => {};
      desc.get = fn;
      assertStrictEquals(desc.get, fn);
    });

    it("[[Set]] throws if not callable or undefined", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() => desc.get = null);
    });

    it("[[Set]] throws if a data property is defined", () => {
      const desc = new PropertyDescriptor({ value: undefined });
      assertThrows(() => desc.get = undefined);
    });

    it("[[Delete]] works", () => {
      const desc = new PropertyDescriptor({ get: undefined });
      delete desc.get;
      assert(!("get" in desc));
    });
  });

  describe("~set", () => {
    it("[[DefineOwnProperty]] works", () => {
      const desc = new PropertyDescriptor({});
      Object.defineProperty(desc, "set", {});
      assertStrictEquals(desc.set, undefined);
    });

    it("[[DefineOwnProperty]] throws for accessor properties", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() =>
        Object.defineProperty(desc, "set", { get: undefined })
      );
    });

    it("[[DefineOwnProperty]] throws if not callable or undefined", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(
        () => Object.defineProperty(desc, "set", { value: null }),
      );
    });

    it("[[DefineOwnProperty]] throws if a data property is defined", () => {
      const desc = new PropertyDescriptor({ value: undefined });
      assertThrows(() => Object.defineProperty(desc, "set", {}));
    });

    it("[[Set]] works", () => {
      const desc = new PropertyDescriptor({});
      const fn = (_) => {};
      desc.set = fn;
      assertStrictEquals(desc.set, fn);
    });

    it("[[Set]] throws if not callable or undefined", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() => desc.set = null);
    });

    it("[[Set]] throws if a data property is defined", () => {
      const desc = new PropertyDescriptor({ value: undefined });
      assertThrows(() => desc.set = undefined);
    });

    it("[[Delete]] works", () => {
      const desc = new PropertyDescriptor({ set: undefined });
      delete desc.set;
      assert(!("set" in desc));
    });
  });

  describe("~value", () => {
    it("[[DefineOwnProperty]] works", () => {
      const desc = new PropertyDescriptor({});
      Object.defineProperty(desc, "value", {});
      assertStrictEquals(desc.value, undefined);
    });

    it("[[DefineOwnProperty]] throws for accessor properties", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() =>
        Object.defineProperty(desc, "value", { get: undefined })
      );
    });

    it("[[DefineOwnProperty]] throws if an accessor property is defined", () => {
      const desc = new PropertyDescriptor({ get: undefined });
      assertThrows(() => Object.defineProperty(desc, "value", {}));
    });

    it("[[Set]] works", () => {
      const desc = new PropertyDescriptor({});
      desc.value = "success";
      assertStrictEquals(desc.value, "success");
    });

    it("[[Set]] throws if an accessor property is defined", () => {
      const desc = new PropertyDescriptor({ get: undefined });
      assertThrows(() => desc.value = null);
    });

    it("[[Delete]] works", () => {
      const desc = new PropertyDescriptor({ value: undefined });
      delete desc.value;
      assert(!("value" in desc));
    });
  });

  describe("~writable", () => {
    it("[[DefineOwnProperty]] coerces to a boolean", () => {
      const desc = new PropertyDescriptor({});
      Object.defineProperty(desc, "writable", {});
      assertStrictEquals(desc.writable, false);
    });

    it("[[DefineOwnProperty]] throws for accessor properties", () => {
      const desc = new PropertyDescriptor({});
      assertThrows(() =>
        Object.defineProperty(desc, "writable", { get: undefined })
      );
    });

    it("[[DefineOwnProperty]] throws if an accessor property is defined", () => {
      const desc = new PropertyDescriptor({ get: undefined });
      assertThrows(() => Object.defineProperty(desc, "writable", {}));
    });

    it("[[Set]] coerces to a boolean", () => {
      const desc = new PropertyDescriptor({});
      desc.writable = undefined;
      assertStrictEquals(desc.writable, false);
    });

    it("[[Set]] throws if an accessor property is defined", () => {
      const desc = new PropertyDescriptor({ get: undefined });
      assertThrows(() => desc.writable = false);
    });

    it("[[Delete]] works", () => {
      const desc = new PropertyDescriptor({ writable: false });
      delete desc.writable;
      assert(!("writable" in desc));
    });
  });
});

describe("defineOwnProperty", () => {
  it("[[Call]] defines the property", () => {
    const obj = {};
    defineOwnProperty(obj, "etaoin", {});
    assert("etaoin" in obj);
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(defineOwnProperty(obj, "etaoin", {}), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new defineOwnProperty(obj, "etaoin", {}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(defineOwnProperty.length, 3);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        defineOwnProperty.name,
        "defineOwnProperty",
      );
    });
  });
});

describe("defineOwnProperties", () => {
  it("[[Call]] defines properties from the provided objects", () => {
    const obj = {};
    defineOwnProperties(obj, {
      etaoin: {},
      shrdlu: {},
    }, { cmfwyp: {} });
    assert("etaoin" in obj);
    assert("shrdlu" in obj);
    assert("cmfwyp" in obj);
  });

  it("[[Call]] overrides earlier declarations with later ones", () => {
    const obj = { etaoin: undefined };
    defineOwnProperties(obj, {
      etaoin: { value: "failure" },
    }, {
      etaoin: { value: "success" },
    });
    assertStrictEquals(obj.etaoin, "success");
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(defineOwnProperties(obj), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new defineOwnProperties({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(defineOwnProperties.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        defineOwnProperties.name,
        "defineOwnProperties",
      );
    });
  });
});

describe("deleteOwnProperty", () => {
  it("[[Call]] deletes the provided property on the provided object", () => {
    const obj = { failure: undefined };
    deleteOwnProperty(obj, "failure");
    assert(!("failure" in obj));
  });

  it("[[Call]] does nothing if the property doesn’t exist", () => {
    const obj = Object.freeze({});
    deleteOwnProperty(obj, "failure");
    assert(!("failure" in obj));
  });

  it("[[Call]] throws if the property can’t be deleted", () => {
    const obj = Object.seal({ failure: undefined });
    assertThrows(() => deleteOwnProperty(obj, "failure"));
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(deleteOwnProperty(obj, ""), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new deleteOwnProperty({}, ""));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(deleteOwnProperty.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(deleteOwnProperty.name, "deleteOwnProperty");
    });
  });
});

describe("freeze", () => {
  it("[[Call]] freezes the object", () => {
    const obj = {};
    freeze(obj);
    assert(Object.isFrozen(obj));
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(freeze(obj), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new freeze({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(freeze.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(freeze.name, "freeze");
    });
  });
});

describe("frozenCopy", () => {
  it("[[Call]] returns a frozen object", () => {
    assert(
      Object.isFrozen(
        frozenCopy(Object.create(null), {
          data: {
            configurable: true,
            enumerable: true,
            value: undefined,
            writable: true,
          },
          accessor: {
            configurable: true,
            enumerable: true,
            get: undefined,
          },
        }),
      ),
    );
  });

  it("[[Call]] ignores non·enumerable properties", () => {
    assertEquals(
      frozenCopy(
        Object.create(null, {
          data: { value: undefined },
          accessor: { get: undefined },
        }),
      ),
      {},
    );
  });

  it("[[Call]] preserves accessor properties", () => {
    const properties = {
      both: {
        configurable: false,
        enumerable: true,
        get: () => {},
        set: (_) => {},
      },
      empty: {
        configurable: false,
        enumerable: true,
        get: undefined,
        set: undefined,
      },
      getter: {
        configurable: false,
        enumerable: true,
        get: () => {},
        set: undefined,
      },
      setter: {
        configurable: false,
        enumerable: true,
        get: undefined,
        set: (_) => {},
      },
    };
    assertEquals(
      Object.getOwnPropertyDescriptors(
        frozenCopy(Object.create(null, properties)),
      ),
      properties,
    );
  });

  it("[[Call]] does not copy properties on the prototype", () => {
    assert(
      !("failure" in
        frozenCopy(Object.create({ failure: undefined }), {
          data: {
            configurable: true,
            value: undefined,
            writable: true,
          },
          accessor: { configurable: true, get: undefined },
        })),
    );
  });

  it("[[Call]] uses the species of the constructor", () => {
    const species = { prototype: {} };
    assertStrictEquals(
      Object.getPrototypeOf(
        frozenCopy({}, { [Symbol.species]: species }),
      ),
      species.prototype,
    );
  });

  it("[[Call]] uses constructor if no species is defined", () => {
    const constructor = { [Symbol.species]: null, prototype: {} };
    assertStrictEquals(
      Object.getPrototypeOf(frozenCopy({}, constructor)),
      constructor.prototype,
    );
  });

  it("[[Call]] uses the constructor on the object if none is provided", () => {
    const constructor = { [Symbol.species]: null, prototype: {} };
    assertStrictEquals(
      Object.getPrototypeOf(frozenCopy({ constructor })),
      constructor.prototype,
    );
  });

  it("[[Call]] allows a null constructor", () => {
    assertStrictEquals(
      Object.getPrototypeOf(frozenCopy({}, null)),
      null,
    );
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new frozenCopy({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(frozenCopy.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(frozenCopy.name, "frozenCopy");
    });
  });
});

describe("getMethod", () => {
  it("[[Call]] gets a method", () => {
    const method = () => {};
    assertStrictEquals(getMethod({ method }, "method"), method);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertEquals(getMethod("", "toString"), String.prototype.toString);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => getMethod(null, "valueOf"));
    assertThrows(() => getMethod(undefined, "valueOf"));
  });

  it("[[Call]] throws if the resulting value isn’t callable", () => {
    assertThrows(() => getMethod({ "failure": true }, "failure"));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getMethod({ method() {} }, "method"));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getMethod.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(getMethod.name, "getMethod");
    });
  });
});

describe("getOwnPropertyDescriptor", () => {
  it("[[Call]] gets the descriptor", () => {
    assertEquals(
      getOwnPropertyDescriptor({ success: true }, "success"),
      {
        configurable: true,
        enumerable: true,
        value: true,
        writable: true,
      },
    );
  });

  it("[[Call]] returns undefined for non‐own properties", () => {
    assertStrictEquals(
      getOwnPropertyDescriptor({}, "valueOf"),
      undefined,
    );
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getOwnPropertyDescriptor({}, ""));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getOwnPropertyDescriptor.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        getOwnPropertyDescriptor.name,
        "getOwnPropertyDescriptor",
      );
    });
  });
});

describe("getOwnPropertyDescriptors", () => {
  it("[[Call]] gets the descriptors", () => {
    assertEquals(
      getOwnPropertyDescriptors({ success: true, etaoin: "shrdlu" }),
      {
        success: {
          configurable: true,
          enumerable: true,
          value: true,
          writable: true,
        },
        etaoin: {
          configurable: true,
          enumerable: true,
          value: "shrdlu",
          writable: true,
        },
      },
    );
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getOwnPropertyDescriptors({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getOwnPropertyDescriptors.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        getOwnPropertyDescriptors.name,
        "getOwnPropertyDescriptors",
      );
    });
  });
});

describe("getOwnPropertyKeys", () => {
  it("[[Call]] gets own (but not inherited) property keys", () => {
    assertEquals(getOwnPropertyKeys({ success: true }), ["success"]);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertEquals(getOwnPropertyKeys("foo"), ["0", "1", "2", "length"]);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => getOwnPropertyKeys(null));
    assertThrows(() => getOwnPropertyKeys(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getOwnPropertyKeys({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getOwnPropertyKeys.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        getOwnPropertyKeys.name,
        "getOwnPropertyKeys",
      );
    });
  });
});

describe("getOwnPropertyStrings", () => {
  it("[[Call]] gets own string keys", () => {
    assertEquals(getOwnPropertyStrings({ success: true }), [
      "success",
    ]);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertEquals(getOwnPropertyStrings("foo"), [
      "0",
      "1",
      "2",
      "length",
    ]);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => getOwnPropertyStrings(null));
    assertThrows(() => getOwnPropertyStrings(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getOwnPropertyStrings({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getOwnPropertyStrings.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        getOwnPropertyStrings.name,
        "getOwnPropertyStrings",
      );
    });
  });
});

describe("getOwnPropertySymbols", () => {
  it("[[Call]] gets own symbol keys", () => {
    const sym = Symbol();
    assertEquals(getOwnPropertySymbols({ [sym]: true }), [sym]);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertEquals(getOwnPropertySymbols("foo"), []);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => getOwnPropertySymbols(null));
    assertThrows(() => getOwnPropertySymbols(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getOwnPropertySymbols({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getOwnPropertySymbols.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        getOwnPropertySymbols.name,
        "getOwnPropertySymbols",
      );
    });
  });
});

describe("getPropertyValue", () => {
  it("[[Call]] gets property values on the provided object", () => {
    assertStrictEquals(
      getPropertyValue({ success: true }, "success"),
      true,
    );
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertStrictEquals(
      getPropertyValue("", "toString"),
      String.prototype.toString,
    );
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => getPropertyValue(null, "valueOf"));
    assertThrows(() => getPropertyValue(undefined, "valueOf"));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getPropertyValue({}, "valueOf"));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getPropertyValue.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(getPropertyValue.name, "getPropertyValue");
    });
  });
});

describe("getPrototype", () => {
  it("[[Call]] gets object prototypes", () => {
    assertStrictEquals(getPrototype({}), Object.prototype);
    const proto = {};
    assertStrictEquals(getPrototype(Object.create(proto)), proto);
  });

  it("[[Call]] gets null prototypes", () => {
    assertStrictEquals(getPrototype(Object.create(null)), null);
  });

  it("[[Call]] gets prototypes for coercible primitives", () => {
    assertStrictEquals(getPrototype(1), Number.prototype);
    assertStrictEquals(getPrototype(Symbol()), Symbol.prototype);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => getPrototype(null));
    assertThrows(() => getPrototype(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new getPrototype({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(getPrototype.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(getPrototype.name, "getPrototype");
    });
  });
});

describe("hasProperty", () => {
  it("[[Call]] gets whether a property exists on the provided object", () => {
    assertStrictEquals(
      hasProperty({ success: "etaoin" }, "success"),
      true,
    );
    assertStrictEquals(hasProperty({}, "hasOwnProperty"), true);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertStrictEquals(hasProperty("", "length"), true);
    assertStrictEquals(hasProperty("", "toString"), true);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => hasProperty(null, "valueOf"));
    assertThrows(() => hasProperty(undefined, "valueOf"));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new hasProperty({}, "valueOf"));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(hasProperty.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(hasProperty.name, "hasProperty");
    });
  });
});

describe("hasOwnProperty", () => {
  it("[[Call]] gets whether an own property exists on the provided object", () => {
    assertStrictEquals(
      hasOwnProperty({ success: "etaoin" }, "success"),
      true,
    );
    assertStrictEquals(hasOwnProperty({}, "hasOwnProperty"), false);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertStrictEquals(hasOwnProperty("", "length"), true);
    assertStrictEquals(hasOwnProperty("", "toString"), false);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => hasOwnProperty(null, "valueOf"));
    assertThrows(() => hasOwnProperty(undefined, "valueOf"));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new hasOwnProperty({}, "valueOf"));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(hasOwnProperty.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(hasOwnProperty.name, "hasOwnProperty");
    });
  });
});

describe("isExtensibleObject", () => {
  it("[[Call]] returns true for extensible objects", () => {
    assertStrictEquals(isExtensibleObject({}), true);
  });

  it("[[Call]] returns false for coercible primitives", () => {
    assertStrictEquals(isExtensibleObject(1), false);
    assertStrictEquals(isExtensibleObject(Symbol()), false);
  });

  it("[[Call]] returns false for non·extensible objects", () => {
    assertStrictEquals(
      isExtensibleObject(Object.preventExtensions({})),
      false,
    );
  });

  it("[[Call]] returns false for null and undefined", () => {
    assertStrictEquals(isExtensibleObject(null), false);
    assertStrictEquals(isExtensibleObject(undefined), false);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new isExtensibleObject({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(isExtensibleObject.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(
        isExtensibleObject.name,
        "isExtensibleObject",
      );
    });
  });
});

describe("isUnfrozenObject", () => {
  it("[[Call]] returns true for unfrozen objects", () => {
    assertStrictEquals(isUnfrozenObject({}), true);
  });

  it("[[Call]] returns false for coercible primitives", () => {
    assertStrictEquals(isUnfrozenObject(1), false);
    assertStrictEquals(isUnfrozenObject(Symbol()), false);
  });

  it("[[Call]] returns false for frozen objects", () => {
    assertStrictEquals(isUnfrozenObject(Object.freeze({})), false);
  });

  it("[[Call]] returns false for null and undefined", () => {
    assertStrictEquals(isUnfrozenObject(null), false);
    assertStrictEquals(isUnfrozenObject(undefined), false);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new isUnfrozenObject({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(isUnfrozenObject.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(isUnfrozenObject.name, "isUnfrozenObject");
    });
  });
});

describe("isUnsealedObject", () => {
  it("[[Call]] returns true for unsealed objects", () => {
    assertStrictEquals(isUnsealedObject({}), true);
  });

  it("[[Call]] returns false for coercible primitives", () => {
    assertStrictEquals(isUnsealedObject(1), false);
    assertStrictEquals(isUnsealedObject(Symbol()), false);
  });

  it("[[Call]] returns false for sealed objects", () => {
    assertStrictEquals(isUnsealedObject(Object.seal({})), false);
  });

  it("[[Call]] returns false for null and undefined", () => {
    assertStrictEquals(isUnsealedObject(null), false);
    assertStrictEquals(isUnsealedObject(undefined), false);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new isUnsealedObject({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(isUnsealedObject.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(isUnsealedObject.name, "isUnsealedObject");
    });
  });
});

describe("namedEntries", () => {
  it("[[Call]] gets named entries", () => {
    assertEquals(namedEntries({ success: true }), [["success", true]]);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertEquals(namedEntries("foo"), [
      ["0", "f"],
      ["1", "o"],
      ["2", "o"],
    ]);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => namedEntries(null));
    assertThrows(() => namedEntries(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new namedEntries({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(namedEntries.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(namedEntries.name, "namedEntries");
    });
  });
});

describe("namedKeys", () => {
  it("[[Call]] gets named keys", () => {
    assertEquals(namedKeys({ success: true }), ["success"]);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertEquals(namedKeys("foo"), [
      "0",
      "1",
      "2",
    ]);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => namedKeys(null));
    assertThrows(() => namedKeys(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new namedKeys({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(namedKeys.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(namedKeys.name, "namedKeys");
    });
  });
});

describe("namedValues", () => {
  it("[[Call]] gets named values", () => {
    assertEquals(namedValues({ success: true }), [true]);
  });

  it("[[Call]] works for values coercible to objects", () => {
    assertEquals(namedValues("foo"), [
      "f",
      "o",
      "o",
    ]);
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => namedValues(null));
    assertThrows(() => namedValues(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new namedValues({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(namedValues.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(namedValues.name, "namedValues");
    });
  });
});

describe("objectCreate", () => {
  it("[[Call]] creates an object", () => {
    const obj = objectCreate(null);
    assertStrictEquals(Object(obj), obj);
  });

  it("[[Call]] correctly sets the prototype", () => {
    const proto = {};
    assertStrictEquals(
      Object.getPrototypeOf(objectCreate(proto)),
      proto,
    );
    assertStrictEquals(
      Object.getPrototypeOf(objectCreate(null)),
      null,
    );
  });

  it("[[Call]] correctly sets own properties", () => {
    assertEquals(
      Object.getOwnPropertyDescriptors(
        objectCreate(null, { success: { value: true } }),
      ),
      {
        success: {
          configurable: false,
          enumerable: false,
          value: true,
          writable: false,
        },
      },
    );
  });

  it("[[Call]] throws for coercible primitives", () => {
    assertThrows(() => objectCreate(1));
    assertThrows(() => objectCreate(Symbol()));
  });

  it("[[Call]] throws for undefined", () => {
    assertThrows(() => objectCreate(undefined));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new objectCreate({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(objectCreate.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(objectCreate.name, "objectCreate");
    });
  });
});

describe("objectFromEntries", () => {
  it("[[Call]] creates an object", () => {
    const obj = objectFromEntries([]);
    assertStrictEquals(Object(obj), obj);
  });

  it("[[Call]] correctly sets the prototype", () => {
    assertStrictEquals(
      Object.getPrototypeOf(objectFromEntries([])),
      Object.prototype,
    );
  });

  it("[[Call]] correctly sets own properties", () => {
    assertEquals(
      Object.entries(objectFromEntries([["success", true]])),
      [["success", true]],
    );
  });

  it("[[Call]] throws if the argument is not a nested arraylike", () => {
    assertThrows(() => objectFromEntries(1));
    assertThrows(() => objectFromEntries(Symbol()));
    assertThrows(() => objectFromEntries(null));
    assertThrows(() => objectFromEntries(undefined));
    assertThrows(() => objectFromEntries({}));
    assertThrows(() => objectFromEntries([undefined]));
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new objectFromEntries([]));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(objectFromEntries.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(objectFromEntries.name, "objectFromEntries");
    });
  });
});

describe("preventExtensions", () => {
  it("[[Call]] prevents extensions on the object", () => {
    const obj = {};
    preventExtensions(obj);
    assert(!Object.isExtensible(obj));
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(preventExtensions(obj), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new preventExtensions({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(preventExtensions.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(preventExtensions.name, "preventExtensions");
    });
  });
});

describe("seal", () => {
  it("[[Call]] seals the object", () => {
    const obj = {};
    seal(obj);
    assert(Object.isSealed(obj));
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(seal(obj), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new seal({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(seal.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(seal.name, "seal");
    });
  });
});

describe("setPropertyValue", () => {
  it("[[Call]] sets the provided property on the provided object", () => {
    const obj = {};
    setPropertyValue(obj, "success", true);
    assertStrictEquals(obj.success, true);
  });

  it("[[Call]] calls setters", () => {
    const setter = spy((_) => {});
    const obj = Object.create(null, { success: { set: setter } });
    setPropertyValue(obj, "success", true);
    assertSpyCalls(setter, 1);
    assertSpyCall(setter, 0, {
      args: [true],
      self: obj,
    });
  });

  it("[[Call]] walks the prototype chain", () => {
    const setter = spy((_) => {});
    const obj = Object.create(
      Object.create(null, { success: { set: setter } }),
    );
    setPropertyValue(obj, "success", true);
    assertSpyCalls(setter, 1);
    assertSpyCall(setter, 0, {
      args: [true],
      self: obj,
    });
  });

  it("[[Call]] uses the provided receiver", () => {
    const setter = spy((_) => {});
    const obj = Object.create(null, { success: { set: setter } });
    const receiver = {};
    setPropertyValue(obj, "success", true, receiver);
    assertSpyCalls(setter, 1);
    assertSpyCall(setter, 0, {
      args: [true],
      self: receiver,
    });
  });

  it("[[Call]] throws if the property can’t be set", () => {
    const obj = Object.freeze({ failure: undefined });
    assertThrows(() => setPropertyValue(obj, "failure", true));
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(setPropertyValue(obj, "", undefined), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new setPropertyValue({}, "", undefined));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(setPropertyValue.length, 3);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(setPropertyValue.name, "setPropertyValue");
    });
  });
});

describe("setPropertyValues", () => {
  it("[[Call]] sets the provided properties on the provided object", () => {
    const obj = {};
    setPropertyValues(obj, { success: true, all: "good" });
    assertStrictEquals(obj.success, true);
    assertStrictEquals(obj.all, "good");
  });

  it("[[Call]] can take multiple objects", () => {
    const obj = {};
    setPropertyValues(
      obj,
      { success: false, all: "good" },
      { success: true },
    );
    assertStrictEquals(obj.success, true);
    assertStrictEquals(obj.all, "good");
  });

  it("[[Call]] ignores nullish arguments", () => {
    const obj = {};
    setPropertyValues(obj, null, undefined, { success: true });
    assertStrictEquals(obj.success, true);
  });

  it("[[Call]] calls setters", () => {
    const setter = spy((_) => {});
    const obj = Object.create(null, { success: { set: setter } });
    setPropertyValues(obj, { success: true });
    assertSpyCalls(setter, 1);
    assertSpyCall(setter, 0, {
      args: [true],
      self: obj,
    });
  });

  it("[[Call]] calls setters multiple times if property appears more than once", () => {
    const setter = spy((_) => {});
    const obj = Object.create(null, { success: { set: setter } });
    setPropertyValues(obj, { success: false }, { success: true });
    assertSpyCalls(setter, 2);
    assertSpyCall(setter, 0, {
      args: [false],
      self: obj,
    });
    assertSpyCall(setter, 1, {
      args: [true],
      self: obj,
    });
  });

  it("[[Call]] walks the prototype chain", () => {
    const setter = spy((_) => {});
    const obj = Object.create(
      Object.create(null, { success: { set: setter } }),
    );
    setPropertyValues(obj, { success: true });
    assertSpyCalls(setter, 1);
    assertSpyCall(setter, 0, {
      args: [true],
      self: obj,
    });
  });

  it("[[Call]] throws if the property can’t be set", () => {
    const obj = Object.freeze({ failure: undefined });
    assertThrows(() => setPropertyValues(obj, { failure: true }));
  });

  it("[[Call]] returns the provided object", () => {
    const obj = {};
    assertStrictEquals(setPropertyValues(obj, { "": undefined }), obj);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new setPropertyValues(obj, { "": undefined }));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(setPropertyValues.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(setPropertyValues.name, "setPropertyValues");
    });
  });
});

describe("setPrototype", () => {
  it("[[Call]] sets object prototypes", () => {
    const obj = {};
    const proto = {};
    setPrototype(obj, proto);
    assertStrictEquals(Object.getPrototypeOf(obj), proto);
  });

  it("[[Call]] sets null prototypes", () => {
    const obj = {};
    setPrototype(obj, null);
    assertStrictEquals(Object.getPrototypeOf(obj), null);
  });

  it("[[Call]] can set coercible primitives to their same prototype", () => {
    setPrototype(1, Number.prototype);
    setPrototype(Symbol(), Symbol.prototype);
  });

  it("[[Call]] throws when setting coercible primitives to a different prototype", () => {
    assertThrows(() => setPrototype(1, Object.prototype));
    assertThrows(() => setPrototype(Symbol(), Object.prototype));
  });

  it("[[Call]] throws for null and undefined", () => {
    assertThrows(() => setPrototype(null, Object.prototype));
    assertThrows(() => setPrototype(undefined, Object.prototype));
  });

  it("[[Call]] returns the provided value", () => {
    const obj = {};
    assertStrictEquals(setPrototype(obj, null), obj);
    assertStrictEquals(setPrototype(1, Number.prototype), 1);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new setPrototype({}, null));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(setPrototype.length, 2);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(setPrototype.name, "setPrototype");
    });
  });
});

describe("toObject", () => {
  it("returns the input for objects", () => {
    const obj = {};
    assertStrictEquals(toObject(obj), obj);
  });

  it("throws for nullish values", () => {
    assertThrows(() => toObject(null));
    assertThrows(() => toObject(void {}));
  });

  it("returns a wrapper object for other primitives", () => {
    const sym = Symbol();
    assertStrictEquals(typeof toObject(sym), "object");
    assertStrictEquals(toObject(sym).valueOf(), sym);
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new toObject({}));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(toObject.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(toObject.name, "toObject");
    });
  });
});

describe("toPropertyKey", () => {
  it("returns a string or symbol", () => {
    const sym = Symbol();
    assertStrictEquals(toPropertyKey(sym), sym);
    assertStrictEquals(
      toPropertyKey(new String("success")),
      "success",
    );
  });

  it("favours the `toString` representation", () => {
    assertStrictEquals(
      toPropertyKey({
        toString() {
          return "success";
        },
        valueOf() {
          return "failure";
        },
      }),
      "success",
    );
  });

  it("[[Construct]] throws an error", () => {
    assertThrows(() => new toPropertyKey(""));
  });

  describe(".length", () => {
    it("[[Get]] returns the correct length", () => {
      assertStrictEquals(toPropertyKey.length, 1);
    });
  });

  describe(".name", () => {
    it("[[Get]] returns the correct name", () => {
      assertStrictEquals(toPropertyKey.name, "toPropertyKey");
    });
  });
});