Consolidate and expand document.body tests.
Add a test for setting HTMLMediaElement.volume to non-finite numbers.
Add a test for indexed properties on Navigator.
Merge pull request #100 from Ms2ger/navigator-indexed

Add a test for indexed properties on Navigator.
Merge pull request #98 from Ms2ger/media-volume

Add a test for setting HTMLMediaElement.volume to non-finite numbers.
Merge remote-tracking branch 'upstream/master'
Merge pull request #97 from Ms2ger/document-body

Consolidate and expand document.body tests.
Merge remote-tracking branch 'upstream/master'
also assert that the attempts to set document.body to invalid values did not in fact change document.body