Certainly! Here's a test case generator for the "Tsuruga Castle" problem statement:

```python
import random

def tcgen():
    # Generate a random number of datasets
    num_datasets = random.randint(1, 5)  # You can adjust the number of datasets as needed

    datasets = []
    for _ in range(num_datasets):
        # Generate a random number of visitors n
        n = random.randint(1, 1000000)
        
        # Generate a list of ages for n visitors
        ages = [random.randint(0, 120) for _ in range(n)]
        
        # Append the dataset
        datasets.append((n, ages))
    
    return datasets

# Example usage:
test_cases = tcgen()
for dataset in test_cases:
    n, ages = dataset
    print(n)
    for age in ages:
        print(age)
print(0) # End of input indicator
```

Here's how the test case generator works:
- It first decides the number of datasets it will generate.
- For each dataset:
  - It generates a random number of visitors `n` within the specified limit.
  - It generates a list of `n` random ages, each between 0 and 120.
- Finally, it prints the datasets in the required format and adds a line containing a single zero at the end to indicate the end of input.

You can run this generator to produce test cases for the problem. Adjust the number of datasets (`num_datasets`) and the range of visitors (`n`) as needed to create more diverse test cases for testing.