Sure! Here's a test case generator for the problem "Decrypting the Princess's Code".

```python
import random
import string

def generate_word(max_length=10):
    length = random.randint(1, max_length)
    return ''.join(random.choices(string.ascii_lowercase, k=length))

def tcgen():
    datasets = []
    while True:
        N = random.randint(1, 10)
        words = [generate_word() for _ in range(N)]
        datasets.append((N, words))
        
        # Decide randomly whether to stop adding datasets
        if random.choice([True, False]):
            break
    
    return datasets

def format_output(datasets):
    output = []
    for N, words in datasets:
        output.append(str(N))
        output.extend(words)
    output.append("0")
    return '\n'.join(output)

# Example usage
datasets = tcgen()
print(format_output(datasets))
```

This test case generator will create multiple datasets each containing a random number of words (between 1 and 10) consisting of random lowercase letters, and it will format the datasets as required by the problem statement. Each word has a maximum length of 10 characters. The generation of datasets stops randomly to simulate multiple datasets ending with a '0'. 

You can use this generator to create inputs for testing your solution to the given problem. The `format_output` function is used to format the datasets into a string that mimics the input format.

Here's an example of what the output might look like:

```
4
xykwj
a
yze
lmno
3
opqrs
uvwxy
bcd
2
xyz
abc
0
```