rover_test.js

    it("turns right from N to E", () => {
        let rover = {facing: "N"};
        rover = go(rover, "R");
        assert.equal(rover.facing, "E");
    })

    it("turns right from E to S", () => {
        let rover = {facing: "E"};
        rover = go(rover, "R");
        assert.equal(rover.facing, "S");
    })

    it("turns right from S to W", () => {
        let rover = {facing: "S"};
        rover = go(rover, "R");
        assert.equal(rover.facing, "W");
    })

    it("turns right from W to N", () => {
        let rover = {facing: "W"};
        rover = go(rover, "R");
        assert.equal(rover.facing, "N");
    })