One criticism of the sorts of textual analysis that have been employed on the Bible is that the Gettysburg Address would be revealed to have multiple authors.

However, that's an imperfect example, because some of President Lincoln's aides could have done much of the writing of that document; recent US Presidents have been known to hire speechwriters, and it is not unlikely that some aides of earlier Presidents had had similar duties.

Have there been any tests of such textual-analysis methods on documents with known histories?

Opus1

Somebody used textual analysis to prove that "Primary Colors" was written by Jonathan Klein. He denied it. The analyst stuck to her guns and insisted that he must have written it. He finally confessed that he did. This sounds like a pretty solid use of textual analysis to me.

Textual criticism is not a means of destorying the Bible. Most schlars who use it are blievers! It is not a method for proving the bible flase. That is not it's purpose. It was invented by Chrstians and is practiced by Chrsitians for them most part.

Opus1

To Metacrock:

Textual analysis should not be used to either destroy or confirm the Bible. It should be used objectively and followed wherever the evidence takes us. Textual analysis has revealed that the popular belief that Moses wrote the Pentateuch is incorrect. It is irrelevent whether Jews, Christians, or atheists discovered this. A common fundamentalist idea has been refuted by scientific methods (yet again). This is why most fundies hate scholars who use textual analysis.