planning

node_modules/semaphore/test/semaphore.js

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+var should = require('should');
+var assert = require('assert');
+var semaphore = require("../lib/semaphore.js");
+require('mocha');
+
+var Phone = function() {
+	return {
+		state: "free",
+
+		dial: function(callback) {
+			if (this.state != "free") {
+				return callback(new Error("The phone is busy"));
+			}
+
+			this.state = "busy";
+
+			setTimeout(function() {
+				callback();
+			}, 100);
+		},
+
+		hangup: function() {
+			if (this.state == "free") {
+				return callback(new Error("The phone is not in use"));
+			}
+
+			this.state = "free";
+		}
+	};
+};
+
+it("should not be using a bad example", function(done) {
+	var phone = new Phone();
+
+	// Call Bob
+	phone.dial(function(err) {
+		if (err) return done(err);
+
+		phone.hangup();
+	});
+
+	// Cannot call Bret, because the phone is already busy with Bob.
+	phone.dial(function(err) {
+		should.exist(err);
+		done();
+	});
+});
+
+it("should not break the phone", function(done) {
+	var phone = new Phone();
+	var sem = require('../lib/semaphore.js')(1);
+
+	// Call Jane
+	sem.take(function() {
+		phone.dial(function(err) {
+			if (err) return done(err);
+
+			phone.hangup();
+
+			sem.leave();
+		});
+	});
+
+	// Call Jon (will need to wait for call with Jane to complete)
+	sem.take(function() {
+		phone.dial(function(err) {
+			if (err) return done(err);
+
+			phone.hangup();
+
+			sem.leave();
+
+			done();
+		});
+	});
+});
+
+it('should not be slow', function(done) {
+	var s = require('../lib/semaphore.js')(3);
+	var values = [];
+
+	s.take(function() { values.push(1); s.leave(); });
+	s.take(function() { values.push(2); s.leave(); });
+	s.take(function() { values.push(3); s.leave(); });
+	s.take(function() { values.push(4); s.leave(); });
+	s.take(function() { values.push(5); s.leave(); });
+
+	process.nextTick(function() {
+		values.length.should.equal(5);
+		done();
+	});
+});
+
+it('should not let past more than capacity', function(done) {
+	this.timeout(6000);
+
+	var s = require('../lib/semaphore.js')(3);
+	var values = [];
+	var speed = 250;
+
+	s.take(function() { values.push(1); setTimeout(function() { s.leave(); }, speed * 1); });
+	s.take(function() { values.push(2); setTimeout(function() { s.leave(); }, speed * 2); });
+	s.take(function(leave) { values.push(3); setTimeout(function() { leave(); }, speed * 3); });
+	s.take(function() { values.push(4); });
+	s.take(function() { values.push(5); });
+
+	var tickN = 0;
+
+	var check = function() {
+		switch (tickN++) {
+			case 0: // After 0 sec
+				console.log("0 seconds passed.")
+				s.current.should.equal(s.capacity);
+				s.queue.length.should.equal(2);
+				values.should.eql([1, 2, 3]);
+				break;
+			case 1: // After 1 sec
+				console.log("1 seconds passed.");
+				s.current.should.equal(s.capacity);
+				s.queue.length.should.equal(1);
+				values.should.eql([1, 2, 3, 4]);
+				break;
+			case 2: // After 2 sec
+				console.log("2 seconds passed.");
+				s.current.should.equal(3);
+				s.queue.length.should.equal(0);
+				values.should.eql([1, 2, 3, 4, 5]);
+				break;
+			case 3: // After 3 sec
+				console.log("3 seconds passed.");
+				s.current.should.equal(2);
+				s.queue.length.should.equal(0);
+				values.should.eql([1, 2, 3, 4, 5]);
+				return done();
+		}
+
+		setTimeout(check, speed * 1.1);
+	};
+
+	check();
+});
+
+describe("should respect number", function() {
+	it("should fail when taking more than the capacity allows", function(done) {
+		var s = semaphore(1);
+
+		s.take(2, function() {
+			assert.fail();
+		});
+
+		process.nextTick(done);
+	});
+
+	it("should work fine with correct input values", function(done) {
+		var s = semaphore(10); // 10
+
+		s.take(5, function(leave) { // 5
+			s.take(4, function() { // 1
+				leave(4); // 5
+
+				s.take(5, function() {
+					return done()
+				}); // 0
+			});
+		});
+	});
+});