Walkontable Testing

Tests are organized by subsystem: overlay/, scroll/, selection/, renderer/, table/, viewport.spec.js, etc. Place new tests in the directory that matches the subsystem you are modifying.

What to Cover

• Frozen rows and columns: The overlay system (6 overlay types) is the most fragile part of Walkontable. Always include tests with frozen rows/columns to catch overlay positioning and synchronization regressions.
• Viewport calculations: Test with various container sizes (small containers that clip content, containers larger than the data, and containers that resize dynamically).
• Scroll synchronization: Verify that scrolling the main table keeps frozen overlays aligned. Test both horizontal and vertical scroll.
• Large datasets: Include performance-oriented tests with 10k+ rows. Use forEach loops to populate data arrays -- never arr.push(...largeArray).

Common Mistakes

• Running Walkontable tests via test:e2e -- they have their own command and will not execute.
• Skipping frozen row/column scenarios -- this misses the overlay edge cases where most regressions occur.
• Testing only small datasets -- Walkontable bugs often surface at scale.
• Modifying Walkontable test bootstrap/webpack config without verifying that both spec/ and unit/ sub-pipelines still pass.