Sure! Let's create a test case generator for the problem "What is the Number in my Mind?" given its constraints and requirements.

Here’s the Python code for the test case generator:

```python
import random
from itertools import permutations

def generate_number_with_unique_digits(L):
    digits = list('0123456789')
    random.shuffle(digits)
    return ''.join(digits[:L])

def calculate_hits_and_blows(secret, guess):
    hits = sum(s == g for s, g in zip(secret, guess))
    blows = sum(min(secret.count(x), guess.count(x)) for x in set(guess)) - hits
    return hits, blows

def generate_hints(secret, L, H):
    hints = []
    for _ in range(H):
        guess = generate_number_with_unique_digits(L)
        hits, blows = calculate_hits_and_blows(secret, guess)
        hints.append(f"{guess} {hits} {blows}")
    return hints

def tcgen():
    test_cases = []
    while True:
        L = random.randint(4, 10)
        H = random.randint(1, 10)
        if L == 0 and H == 0:
            break
        secret = generate_number_with_unique_digits(L)
        hints = generate_hints(secret, L, H)
        hint_set = f"{L} {H}\n" + "\n".join(hints)
        test_cases.append(hint_set)
        if len(test_cases) >= 5:  # Let's generate 5 hint-sets for illustration
            break

    test_cases.append("0 0")
    return "\n".join(test_cases)

# Example usage:
if __name__ == "__main__":
    print(tcgen())
```

### Explanation:
1. **generate_number_with_unique_digits(L)** - Generates a number of length `L` where all digits are unique.
2. **calculate_hits_and_blows(secret, guess)** - Computes the number of hits and blows for a given secret and guess.
3. **generate_hints(secret, L, H)** - Generates `H` hints for a given secret number.
4. **tcgen()** - Main function to generate multiple hint-sets. It keeps generating hint-sets until it reaches a specified number (5 in this case). It ends the test case generation with the termination line "0 0".

This script will generate valid and varied test cases for the given problem, ensuring each hint-set is correctly formatted and contains plausible hints for the secret number. Adjust the number of hint-sets or the number of hints per set as needed.