Sure, let's create a test case generator for the given problem statement "Flick Input".

First, we need to understand the problem requirements and constraints:

1. The input string consists of digits '0'-'9' and characters 'T', 'L', 'U', 'R', 'D'.
2. The length of the input string is between 2 and 1000 characters.
3. The string starts with a digit and ends with a flick direction character.

We will generate a random input string that adheres to the constraints and then return it.

Here is the code for the test case generator:

```python
import random

def generate_flick_input_test_case():
    # Define the possible digits and flick directions
    digits = '0123456789'
    flick_directions = 'TLURD'
    
    # Generate a random length for the input string between 2 and 1000
    length = random.randint(2, 1000)
    
    # Initialize the input string with a random digit
    input_string = random.choice(digits)
    
    # Generate the rest of the string such that each digit is followed by a flick direction
    while len(input_string) < length - 1:
        input_string += random.choice(flick_directions)
        input_string += random.choice(digits)

    # Ensure the last character is a flick direction
    input_string += random.choice(flick_directions)
    
    return input_string

# Example usage
test_case = generate_flick_input_test_case()
print(test_case)
```

This code will generate a valid test case for the "Flick Input" problem. Here's a brief explanation of the key points:
- We start by defining the possible digits and flick directions.
- We then choose a random length for the input string.
- The input string is constructed by alternating between digits and flick directions.
- Finally, we ensure that the last character of the input string is a flick direction to comply with the problem constraints.

You can run the `generate_flick_input_test_case` function multiple times to generate different test cases for the problem.

