Intellij test run history

On the current version of Intellij (2016), you have now a way to reimport older test Result. On the runner tab, click on the button "Import test Results", and select the one you want

EDIT : In the latest version, you have a "Recent Tests" action which allow you to see older test result without a need to open the rest windows. Shortcut Ctrl+Shift+Semicolon

You can right-click a tab with test results and select the "Pin Tab" option from the context menu. Then further test executions will not overwrite this tab, and you can still refer to it to see which other tests you need to fix.

Not relevant for Idea 13, but in 2021 this functionality is present in Idea. https://www.jetbrains.com/help/idea/viewing-and-exploring-test-results.html#view-previous