Sure, here is a Python function to generate test cases for the given sandglass problem:

```python
import random

def tcgen():
    X = random.randint(1, 10**9)
    t = random.randint(1, 10**9)
    return X, t

# Generate a test case
X, t = tcgen()
print(f"{X} {t}")

# Example usage: output a test case
if __name__ == "__main__":
    for _ in range(5):  # Generate 5 example test cases
        X, t = tcgen()
        print(f"{X} {t}")
```

This function randomly generates values for \(X\) and \(t\) within the specified constraints (1 ≤ \(X\) ≤ 10^9 and 1 ≤ \(t\) ≤ 10^9). The generated values are returned and printed in the required format. You can run this function to generate multiple test cases as needed.

Here's how you can use the function to generate and print multiple test cases:

```python
if __name__ == "__main__":
    for _ in range(5):  # Generate 5 example test cases
        X, t = tcgen()
        print(f"{X} {t}")
```

This will generate 5 test cases and print them in the required format, suitable for use in testing the sandglass problem solution.