def isWordLadder(s: str) -> bool:
    """Check if a string is a word ladder."""
    words = s.split("-")
    if len(words) < 2:
        return False
    if len(words[0]) != len(words[-1]):
        return False
    if len(set(words)) != len(words):
        return False
    for i in range(len(words) - 1):
        if len(words[i]) != len(words[i + 1]):
            return False
        diff = 0
        for j in range(len(words[i])):
            if words[i][j] != words[i + 1][j]:
                diff += 1
        if diff != 1:
            return False
    return True


print("Testing isWordLadder()...", end="")
assert isWordLadder("dog-cog-cot-cat") == True
assert isWordLadder("cat-bat") == True
assert isWordLadder("cold-cord-card-ward-warm") == True
assert isWordLadder("toggle-goggle-google") == True
assert isWordLadder("cold-cord-card-warm") == False
assert isWordLadder("cat-bat-cat") == False  # duplicate word
assert isWordLadder("cat-bat-") == False
assert isWordLadder("cat-cats") == False
assert isWordLadder("cat-cabs") == False
assert isWordLadder("cat") == False  # just one word
assert isWordLadder("") == False  # no words
assert isWordLadder("-") == False  # no words
print("Passed!")