How can I test IE10 on Mac?

That page no longer appears to be up-to-date.

However, Microsoft's developer website provides free download links to test Microsoft Edge and Internet Explorer (versions 8 through 11) using virtual machines. You can manage them locally using VirtualBox or another virtualization software tool.

The modern.IE link doesn't work anymore, but Microsoft has virtual machine downloads available for IE versions 8-11 and Edge.

1. Open Safari and navigate to Safari > Preferences from the menu bar.
2. Click on the Advanced tab.
3. Check the "Show Develop menu in menu bar" setting, then close the Preferences window.
4. The Develop menu should now show in your menu bar.
5. Go to Develop > User Agent.
6. Here, you have to option to choose different browser options like Microsoft Edge, Internet Explorer 7, 8, 9, 10 and 11. You can also choose Firefox and Chrome as the User Agent.

Source: How to view websites on your Mac that require Internet Explorer (or a PC)