Lex empty input to []. Fixes #430.

Author: vlad-shatskyi

src/CommandExpander.ts

@@ -26,6 +26,10 @@ export async function expandAliases(lexemes: string[]): Promise<string[]> {
 }
 
 export function lex(input: string): string[] {
+    if (input.length === 0) {
+        return [];
+    }
+
     let lexemes = input.match(/"(?:\\"|[^"])+"|'(?:\\'|[^'])+'|(?:[^ ]+\\ )+[^ ]+|[^ ]+/g);
 
     if (input.endsWith(" ")) {

test/lexer_spec.ts

@@ -2,6 +2,10 @@ import {expect} from "chai";
 import {lex} from "../src/CommandExpander";
 
 describe("lex", () => {
+    it("returns an empty array on empty input", () => {
+        expect(lex("")).to.eql([]);
+    });
+
     it("splits on a space", () => {
         expect(lex("some words")).to.eql(["some", "words"]);
     });

test/pty_spec.ts

@@ -2,7 +2,7 @@ import {expect} from "chai";
 import PTY from "../src/PTY";
 
 describe("PTY", () => {
-    it.only("doesn't interpolate expressions inside single quotes", (done) => {
+    it("doesn't interpolate expressions inside single quotes", (done) => {
         let output = "";
         new PTY(
             "echo", ["'$('"], process.env, {columns: 80, rows: 30},