[expect] More promise specific test cases

gunner/lib/assertPromise.js

@@ -1,3 +1,6 @@
-const _assertPromise = (bool, assertion) => bool ? Promise.resolve() : Promise.reject(assertion);
+const _assertPromise = (bool, assertion) => {
+	if(bool && typeof bool.then === 'function') return bool.catch(() => Promise.reject(assertion));
+	return bool ? Promise.resolve() : Promise.reject(assertion);
+};
 
 module.exports = _assertPromise;

gunner/lib/expect.js

@@ -1,32 +1,73 @@
 const isEq = require('@codefeathers/iseq');
 
-const { liftPromise, stringify } = require('../../util/helpers');
+const { stringify } = require('../../util/helpers');
 const _assertPromise = require('./assertPromise');
 
+const expectPromise = (pred, statement, options = {}) => a => (...b) => {
+	if(a && typeof a.then === 'function') {
+		return (
+			a
+			.then(x =>
+				_assertPromise(
+					pred(a, ...b),
+					statement(x, ...b)
+				)
+			)
+			.catch(e =>
+				(options.shouldNotCatch)
+					? _assertPromise(
+						pred(a, ...b),
+						statement(e, ...b)
+					)
+					: Promise.reject(e)
+			)
+		);
+	}
+	return _assertPromise(
+		pred(a, ...b),
+		statement(a, ...b)
+	);
+};
+
 const expect = a => {
 
 	return ({
 		done : () => Promise.resolve(),
-		equal : (b) =>
-			liftPromise(
-				x => _assertPromise(
-					x === b,
-					`${a} is not equal to ${b}`),
-				a),
-		deepEqual : b =>
-			liftPromise(
-				x => _assertPromise(
-					isEq(x, b),
-					`${stringify(a)} is not deeply equal to ${stringify(b)}`,
-					a),
-				a),
-		isTrue : () =>
-			liftPromise(
-				x => _assertPromise(
-					x === true,
-					`${a} is not true`),
-				a),
+		equal : expectPromise(
+			(a, b) => a === b,
+			(a, b) => `${a} is not equal to ${b}`,
+		)(a),
+		deepEqual : expectPromise(
+			(a, b) => isEq(a, b),
+			(a, b) => `${stringify(a)} is not deeply equal to ${stringify(b)}`,
+		)(a),
+		isTrue : expectPromise(
+			a => a === true,
+			a => `${a} is not true`,
+		)(a),
+		hasProp : expectPromise(
+			(a, b) => b in a,
+			(a, b) => `Property ${b} does not exist in ${stringify(a)}`,
+		)(a),
+		hasPair : expectPromise(
+			(a, b, c) => a[b] === c,
+			(a, b, c) => `Pair <${b}, ${c}> does not exist in ${stringify(a)}`,
+		)(a),
+		resolvesTo : expectPromise(
+			(a, b) => (a && typeof a.then === 'function')
+				? a.then(x => x === b ? Promise.resolve() : Promise.reject())
+				: Promise.reject(`${a} was not a Promise`),
+			(a, b) => `${a} does not resolve to ${b}`,
+		)(a),
+		isPromise : expectPromise(
+			a => (a && typeof a.then === 'function')
+				? a.then(() => Promise.resolve()).catch(() => Promise.resolve())
+				: Promise.reject(),
+			a => `${a} is not a Promise`,
+			{ shouldNotCatch: true },
+		)(a),
 	});
+
 };
 
 module.exports = expect;