When testing algorithms, verify their actual functionality rather than just checking for proper instantiation or property modification. Ensure your tests capture the core behaviors of the algorithm under various parameters.

For deterministic algorithms:

For non-deterministic algorithms:

Example:

# Insufficient test - only checks properties
def test_fixed_length_weak():
    pretok = FixedLength(length=5)
    assert pretok.length == 5
    
    pretok.length = 10
    assert pretok.length == 10

# Better test - verifies actual algorithm behavior
def test_fixed_length_complete():
    test_string = "This is a test string for tokenization"
    
    # Test with length=5
    pretok = FixedLength(length=5)
    output_5 = pretok.pre_tokenize(test_string)
    assert len(output_5[0]) == 5  # First chunk should be 5 chars
    assert "".join([t for t, _ in output_5]) == test_string  # Original text preserved
    
    # Test with length=10
    pretok.length = 10
    output_10 = pretok.pre_tokenize(test_string)
    assert len(output_10[0]) == 10  # First chunk should be 10 chars
    assert len(output_10) < len(output_5)  # Fewer chunks with larger length

For algorithms with inherent variability (like probabilistic models), focus on testing stable properties rather than specific outputs that might change between runs.