Sure! A test case generator for the given problem statement could look like the following. This Python function will randomly generate valid input data sets according to the constraints provided in the problem statement.

```python
import random

def tcgen():
    # Generate a number of datasets
    num_datasets = random.randint(1, 100)
    
    datasets = []
    for _ in range(num_datasets):
        # Generate N
        N = random.randint(1, 10**5)
        
        # Generate pw
        pw = random.randint(1, 100)
        
        # Generate flower data
        flowers = []
        for _ in range(N):
            vw = random.randint(-100, 100)
            pf = random.randint(1, 100)
            vf = random.randint(1, 100)
            th = random.randint(-100, 100)
            flowers.append((vw, pf, vf, th))
        
        # Append the dataset
        datasets.append((N, pw, flowers))
    
    # End of input indicated by a zero
    datasets.append(0)
    
    return datasets

def format_datasets(datasets):
    lines = []
    for dataset in datasets:
        if dataset == 0:
            lines.append("0")
        else:
            N, pw, flowers = dataset
            lines.append(str(N))
            lines.append(str(pw))
            for vw, pf, vf, th in flowers:
                lines.append(f"{vw} {pf} {vf} {th}")
    return "\n".join(lines)

# Generate the test cases
datasets = tcgen()
formatted_datasets = format_datasets(datasets)

print(formatted_datasets)
```

This function `tcgen` generates a random number of datasets, each with parameters \(N\), \(pw\), and a list of tuples representing the values \(\mathit{vw}_i\), \(\mathit{pf}_i\), \(\mathit{vf}_i\), and \(\mathit{th}_i\). The `format_datasets` function is used to format these datasets into the required input format for the problem statement.

You can run `print(formatted_datasets)` to see a sample of generated test cases formatted as specified in the problem statement.