the result should be padded with empty elements.

You might want to clarify what empty elements mean, because different languages may have different definitions.

Is there some issue with the random tests in ruby? I keep getting failures because it expects an empty array when I return an interleaved array. For example, in one of the random tests, the input was:
3 <<<<
t k 1 0 c l y <<<<
q x 5 <<<<
l 8 o s g a v <<<<
m v <<<<
j k s v r <<<<
b 4 s r f f 3 r <<<<
4 z 0 6 <<<<
<<<<
(each row is an array)
and I got the error message:
Expected: [], instead got: [3, "t", "q", "l", "m", "j", "b", 4, nil, nil, "k", "x", 8, "v", "k", 4, "z", nil, nil, 1, 5, "o", nil, "s", "s", 0, nil, nil, 0, nil, "s", nil, "v", "r", 6, nil, nil, "c", nil, "g", nil, "r", "f", nil, nil, nil, "l", nil, "a", nil, nil, "f", nil, nil, nil, "y", nil, "v", nil, nil, 3, nil, nil, nil, nil, nil, nil, nil, nil, "r", nil, nil]

You say in the assignment: "It should also have a function named sayHello that returns the string passed into the constructor."
You should be more specific with what you mean by "It". Please try to rephrase the sentence.

There is actually no such thing as a "namespace" in Javascript. Therefore, the description needs to explain how to create something that acts like a namespace in Javascript, or it needs to at least provide a link to additional information.

You shouldn't just expect us to have to Google it and figure it out.