node-data-modeling/test/value-descriptions.js

"use strict";

const expect = require("chai").expect;

const dm = require("../src");
const getValueType = require("../src/util/get-value-type");
const createGuardedMap = require("../src/guarded-collections/map");
const createGuardedSet = require("../src/guarded-collections/set");

describe("value descriptions", () => {
	describe("values", () => {
		describe("simple types", () => {
			it("should correctly describe a string", () => {
				expect(getValueType("some string")).to.equal("a string");
			});

			it("should correctly describe a number", () => {
				expect(getValueType(42)).to.equal("a number");
			});

			it("should correctly describe a boolean", () => {
				expect(getValueType(true)).to.equal("a boolean");
			});

			it("should correctly describe null", () => {
				expect(getValueType(null)).to.equal("null");
			});

			it("should correctly describe undefined", () => {
				expect(getValueType(undefined)).to.equal("undefined");
			});

			it("should correctly describe positive Infinity", () => {
				expect(getValueType(Infinity)).to.equal("Infinity");
			});

			it("should correctly describe negative Infinity", () => {
				expect(getValueType(-Infinity)).to.equal("negative Infinity");
			});

			it("should correctly describe NaN", () => {
				expect(getValueType(NaN)).to.equal("NaN");
			});

			it("should correctly describe a RegExp", () => {
				expect(getValueType(new RegExp())).to.equal("a regular expression");
			});

			it("should correctly describe a regular expression literal", () => {
				expect(getValueType(/foo/)).to.equal("a regular expression");
			});
		});

		describe("function types", () => {
			it("should correctly describe a named function", () => {
				function namedFunction() {
					// nothing
				}

				expect(getValueType(namedFunction)).to.equal("a function[namedFunction]");
			});

			it("should correctly describe an anonymous function", () => {
				expect(getValueType(function(){})).to.equal("a function");
			});

			it("should correctly describe an arrow function", () => {
				expect(getValueType(() => {})).to.equal("a function");
			});

			it("should correctly describe a function created through a Function object", () => {
				expect(getValueType(new Function())).to.equal("a function");
			});

			it("should correctly describe a named constructor function", () => {
				function SomeConstructor() {
					// nothing
				}

				SomeConstructor.prototype.someProp = 42;

				expect(getValueType(SomeConstructor)).to.equal("a constructor[SomeConstructor]");
			});

			it("should correctly describe an anonymous constructor function", () => {
				/* NOTE: We're doing some weird IIFE wrapping here to defeat the function name inference introduced in ES6; otherwise we can't test anonymous constructors. */
				(function (SomeConstructor) {
					SomeConstructor.prototype.someProp = 42;
					expect(getValueType(SomeConstructor)).to.equal("a constructor");
				})(function(){});
			});

			it("should correctly describe a guarded named function", () => {
				let func = dm.guard(
					[dm.string(), dm.boolean()],
					dm.nothing(),
					function someNamedFunction(stringArg, booleanArg) {
						// nothing
					}
				);

				expect(getValueType(func)).to.equal("a guarded function[someNamedFunction] (string, boolean) → nothing")
			});

			it("should correctly describe a guarded anonymous function", () => {
				let func = dm.guard(
					[dm.string(), dm.boolean()],
					dm.nothing(),
					function (stringArg, booleanArg) {
						// nothing
					}
				);

				expect(getValueType(func)).to.equal("a guarded function (string, boolean) → nothing")
			});
		});

		describe("collection types", () => {
			it("should correctly describe an array", () => {
				expect(getValueType([])).to.equal("an array");
			});

			it("should correctly describe an object literal", () => {
				expect(getValueType({})).to.equal("an object");
			});

			it("should correctly describe a Map", () => {
				expect(getValueType(new Map())).to.equal("a Map");
			});

			it("should correctly describe a Set", () => {
				expect(getValueType(new Set())).to.equal("a Set");
			});

			/* TODO: Guarded array */

			it("should correctly describe a guarded Map", () => {
				let guardedMap = createGuardedMap(new Map(), dm.boolean(), dm.string(), {});
				expect(getValueType(guardedMap)).to.equal("a Map<string → boolean>");
			});

			it("should correctly describe a guarded Set", () => {
				let guardedSet = createGuardedSet(new Set(), dm.boolean(), null, {});
				expect(getValueType(guardedSet)).to.equal("a Set<boolean>");
			});
		});

		describe("instance types", () => {
			describe("standard types", () => {
				it("should correctly describe a Date", () => {
					expect(getValueType(new Date())).to.equal("an instance of Date");
				});

				it("should correctly describe an Error", () => {
					expect(getValueType(new Error())).to.equal("an instance of Error");
				});
			});

			describe("custom types", () => {
				it("should correctly describe a type", () => {
					let CustomType = dm.createType("CustomType", {
						value: dm.string()
					});

					expect(getValueType(CustomType({
						value: "foo"
					}))).to.equal("an instance of CustomType");
				});
			});
		});
	});

	describe("rules", () => {
		describe("simple types", () => {
			it("should correctly describe a boolean rule", () => {
				expect(getValueType(dm.boolean())).to.equal("a boolean");
			});

			it("should correctly describe a string rule", () => {
				expect(getValueType(dm.string())).to.equal("a string");
			});

			it("should correctly describe a number rule", () => {
				expect(getValueType(dm.number())).to.equal("a number");
			});

			it("should correctly describe a null rule", () => {
				expect(getValueType(dm.null())).to.equal("null");
			});

			it("should correctly describe a undefined rule", () => {
				expect(getValueType(dm.undefined())).to.equal("undefined");
			});

			it("should correctly describe a nothing rule", () => {
				expect(getValueType(dm.nothing())).to.equal("nothing");
			});

			it("should correctly describe an instanceOf rule", () => {
				expect(getValueType(dm.instanceOf(Date))).to.equal("an instance of Date");
			});
		});

		describe("collection types", () => {
			it("should correctly describe a setOf rule", () => {
				let rule = dm.setOf(dm.boolean());
				expect(getValueType(rule)).to.equal("a Set<boolean>");
			});

			it("should correctly describe a mapOf rule", () => {
				let rule = dm.mapOf(dm.string(), dm.boolean());
				expect(getValueType(rule)).to.equal("a Map<string → boolean>");
			});

			/* TODO: Guarded arrays */
		});

		describe("custom types", () => {
			it("should correctly describe a type", () => {
				let CustomType = dm.createType("CustomType", {
					value: dm.string()
				});

				expect(getValueType(CustomType)).to.equal("an instance of CustomType");
			});

			it("should correctly describe a trait", () => {
				let CustomTrait = dm.createTrait("CustomTrait", {
					value: dm.string()
				});

				expect(getValueType(CustomTrait)).to.equal("an instance of a type with the CustomTrait trait");
			});
		});

		describe("modifiers", () => {
			it("should correctly describe an either rule", () => {
				let rule = dm.either(
					dm.string(),
					dm.boolean()
				);

				expect(getValueType(rule)).to.equal("Either<string | boolean>");
			});
		});

		describe("special rules", () => {
			it("should correctly describe a self rule", () => {
				expect(getValueType(dm.self())).to.equal("(self)");
			});

			it("should correctly describe a slot rule", () => {
				expect(getValueType(dm.slot())).to.equal("(slot)");
			});
		});

		describe("guards", () => {
			it("should correctly describe a guarded function rule", () => {
				expect(getValueType(dm.function(
					[dm.string(), dm.boolean()],
					dm.nothing(),
				))).to.equal("a guarded function (string, boolean) → nothing");
			});
		});

		describe("error conditions", () => {
			it("should throw an error when encountering an unrecognized rule", () => {
				expect(() => {
					getValueType({_isTypeRule: true, _butNotReally: false});
				}).to.throw();
			});
		});
	});
});