[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,
  deleteOwnProperty,
  frozenCopy,
  getMethod,
  getOwnPropertyKeys,
  getPropertyValue,
  hasProperty,
  LazyLoader,
  PropertyDescriptor,
  setPropertyValue,
  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("[[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("PropertyDescriptor", () => {
  it("[[Construct]] creates a new PropertyDescriptor", () => {
    assertStrictEquals(
      Object.getPrototypeOf(new PropertyDescriptor({})),
      PropertyDescriptor.prototype,
    );
  });

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

  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("::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("::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("::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("::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("~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("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);
  });
});

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);
  });
});

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,
    );
  });
});

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"));
  });
});

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));
  });
});

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"));
  });
});

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

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

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

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);
  });
});

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);
  });
});

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",
    );
  });
});