Sure, I can help you create a test case generator for the given problem statement "What Color Is The Universe?". Below is the Python code that generates test cases:

```python
import random

def tcgen():
    # Generate a random size for the array |A| (1 ≤ |A| < 1,000,000)
    N = random.randint(1, 10**6)
    
    # Generate the array A with random integers (each integer is less than 2^31)
    A = [random.randint(0, (2**31) - 1) for _ in range(N)]
    
    return N, A

def generate_test_cases(num_cases=5):
    test_cases = []
    for _ in range(num_cases):
        N, A = tcgen()
        test_cases.append((N, A))
    return test_cases

def format_test_cases(test_cases):
    formatted_cases = []
    for N, A in test_cases:
        formatted_case = f"{N}\n" + " ".join(map(str, A))
        formatted_cases.append(formatted_case)
    formatted_cases.append("0")  # End of input
    return "\n\n".join(formatted_cases)

# Generate and format test cases
test_cases = generate_test_cases()
formatted_test_cases = format_test_cases(test_cases)

print(formatted_test_cases)
```

### Explanation:

1. **`tcgen()` function:** Generates a single test case.
   - It creates a random size `N` for the array `A` such that \(1 \leq N < 1,000,000\).
   - It populates the array `A` with `N` random integers, each ranging from `0` to \(2^{31} - 1\).

2. **`generate_test_cases(num_cases=5)` function:** Generates multiple test cases.
   - It creates a list of test cases by calling `tcgen()` a specified number of times (default is 5).

3. **`format_test_cases(test_cases)` function:** Formats the test cases into the required input format.
   - It formats each test case into a string as required, and appends a "0" at the end to signify the end of input.

4. **Printing the formatted test cases:** Concatenates all test cases into a single string and prints them to simulate the input format expected by the problem.

You can adjust the `num_cases` parameter in the `generate_test_cases` function call to generate more or fewer test cases as needed.