diff --git a/ix.js/l2o-tests.ts b/ix.js/l2o-tests.ts
new file mode 100644
index 0000000000..4be2974b3e
--- /dev/null
+++ b/ix.js/l2o-tests.ts
@@ -0,0 +1,160 @@
+///<reference path="l2o.d.ts"/>
+
+var ec_ns = (a: number, b: string) => a.toString() == b;	//equality comparer on number,string
+var ec_nn = (a: number, b: number) => a === b;				//equality comparer on number,number
+var c_nn = (a: number, b: number) => a - b;					//comparer on number,number
+
+// static
+
+var ax = Ix.Enumerable.fromArray([0, 2, 7, 3, 4, 5]);
+
+var bx = Ix.Enumerable.create(() => {
+	var current = ".";
+	return Ix.Enumerator.create(
+		() => { current += "."; return true; },
+		() => current,
+		() => { });
+});
+
+Ix.Enumerator.create(() => true, () => 1);	// without dispose method
+
+var cx = Ix.Enumerable.empty<number>();
+
+var dx = Ix.Enumerable.concat(ax, cx);
+
+var ex = Ix.Enumerable.return(42);
+var fx = Ix.Enumerable.returnValue("42");
+
+var gx = Ix.Enumerable.range(-100, 200);
+
+Ix.Enumerable.repeat(42, 42);
+Ix.Enumerable.repeat(42);		// infinite
+
+Ix.Enumerable.sequenceEqual(ax, fx, ec_ns);
+Ix.Enumerable.sequenceEqual(ax, ex);	// default comparer on same type
+
+// instance
+
+ax.getEnumerator();
+
+ax.aggregate("", (acc, i) => acc + i, acc=> acc.length);
+ax.aggregate("", (acc, i) => acc + i);
+ax.aggregate((acc, i) => acc + i);
+
+ax.reduce((acc, i) => acc + i, 100);
+ax.reduce((acc, i) => acc + i);
+
+ax.all(item => true);
+ax.all(item => true, bx);
+ax.every(item => true);
+ax.every(item => true, bx);
+
+ax.any();
+ax.any(item => true);
+ax.any(item => true, bx);
+ax.some();
+ax.some(item => true);
+ax.some(item => true, bx);
+
+ax.average();
+bx.average(item => item.length);
+ax.min();
+bx.min(item => item.length);
+ax.max();
+bx.max(item => item.length);
+ax.sum();
+bx.sum(item => item.length);
+
+ax.concat(ax, cx, dx, ex, gx);
+
+ax.contains(10);
+ax.contains("10", ec_ns);
+
+ax.count();
+ax.count(item=>false);
+ax.count(item=> false, {});
+
+cx.defaultIfEmpty();
+cx.defaultIfEmpty(10);
+
+dx.distinct();
+dx.distinct((d1, d2) => d1 === d2);
+
+ax.elementAt(2);
+ax.elementAtOrDefault(2);
+
+//ax.except(bx, ec_ns);	// bug https://typescript.codeplex.com/workitem/1841
+bx.except(fx);
+
+ax.first();
+ax.firstOrDefault();
+ax.last();
+ax.lastOrDefault();
+ax.single();
+ax.singleOrDefault();
+
+ax.forEach(a => console.log(a));
+ax.forEach(a => console.log(a), cx);
+
+bx.groupBy<number, string>(b => b.length);
+bx.groupBy(b => b.length, b => "[" + b + "]");
+bx.groupBy(b => b.length, b => "[" + b + "]", (l, values) => l + values.count());
+bx.groupBy(b => b.length, false, (l, values) => l + values.count());
+bx.groupBy(b => b.length, b => "[" + b + "]", (l, values) => l + values.count(), ec_nn);
+bx.groupBy(b => b.length, b => "[" + b + "]", false, (x, y) => x == y);
+bx.groupBy(b => b.length, false, (l, values) => l + values.count(), ec_nn);
+bx.groupBy<number, number>(b => b.length, false, false, ec_nn);
+
+ax.groupJoin(bx, a => a, b => b, (a, b) => [a, b], ec_ns);
+ax.groupJoin(bx, a => a, b => b.length, (a, b) => [a, b]);
+
+ax.join(bx, a => a, b => b, (a, b) => [a, b], ec_ns);
+ax.join(bx, a => a, b => b.length, (a, b) => [a, b]);
+
+//ax.intersect(bx, ec_ns);	// bug https://typescript.codeplex.com/workitem/1841
+ax.intersect(cx);
+ax.union(cx);
+
+ax.orderBy(a=> -a).thenBy(a => a);
+ax.orderBy(a=> -a, c_nn).thenBy(a => a, c_nn);
+ax.orderByDescending(a=> -a).thenByDescending(a => a);
+ax.orderByDescending(a=> -a, c_nn).thenByDescending(a => a, c_nn);
+
+ax.reverse();
+
+ax.select(a=> a.toString());
+ax.select(a=> a.toString(), {});
+ax.map(a=> a.toString());
+ax.map(a=> a.toString(), {});
+
+ax.selectMany(a=> bx);
+ax.selectMany(a=> bx, (a, b) => [a, b]);
+
+ax.sequenceEqual(fx, ec_ns);
+ax.sequenceEqual(ax, ec_nn);
+ax.sequenceEqual(cx);
+
+ax.skip(10);
+ax.skipWhile(a => a > 10);
+ax.take(10);
+ax.takeWhile(a => a > 10);
+
+ax.toArray();
+
+bx.toDictionary(b => b.length, b => 10, ec_nn);
+bx.toDictionary<number, string>(b => b.length, false, ec_nn);
+bx.toDictionary(b => b.length, b => 10);
+bx.toDictionary<number, string>(b => b.length);
+
+bx.toLookup(b => b.length, b => 10, ec_nn);
+bx.toLookup<number, string>(b => b.length, false, ec_nn);
+bx.toLookup(b => b.length, b => 10);
+bx.toLookup<number, string>(b => b.length);
+
+ax.where(a=> a > 10, {});
+ax.where(a=> a > 10);
+ax.filter(a=> a > 10, {});
+ax.filter(a=> a > 10);
+
+ax.zip(bx, (a: number, b: string) => [a, b]);
+ax.zip(bx, (a, b) => [a, b]);