I agree with you entirely that 'testify' is not a transitive verb. I would also say that it does not mean 'feststellen'. 'Testify' means 'give evidence', or, figuratively, 'provide evidence'. 'The body's greenish appearance testified to its lifeless condition.'

You say you would expect 'attest' in this case. I agree that 'attest' means this, but I would not expect it. Rather: 'determine', or, not quite the same, but in many circumstances equivalent, 'certify'.

Incidentally: w/out saves you precisely one finger-movement over 'without'. Is it worth it?

Welcome to the wonderful world of English speakers choosing the wrong word - testify/attest, imply/infer, etc...

Having said that, you find yourself generally understanding what the person is trying to communicate, which lulls them into the false security of thinking they've got away with it.

testified; testifying

1a :  to make a statement based on personal knowledge or belief :  bear witness

b :  to serve as evidence or proof

2:  to express a personal conviction

3:  to make a solemn declaration under oath for the purpose of establishing a fact (as in a court)

1a :  to bear witness to :  attest

b :  to serve as evidence of :  prove

M-W then goes on to give this example (among others): These statistics testify that the program is working.

There's also:

Official and other dignities testified the public appreciation of Auber's works.

I think escoville misspoke in #1.

Nor did I say in the OP that testify is not a transitive verb, merely that its transitive use with a noun (not a phrase as in the M-W example) that is not preceded by a preposition seems incorrect to me.

Testify to, testify against, testify about, testify that are all fine in my eyes.

"He testified the death of the refugees," not so much :-)

escoville is unrepentant (at least as regards BE).

See: https://en.oxforddictionaries.com/definition/...

Note: 'NO OBJECT'

1. (when tr, may take a clause as object)

to state (something) formally as a declaration of fact

I testify that I know nothing about him

Either way, this is getting OT. :-)

Webster's New World Dictionary gives these definitions for the transitive:

1. to bear witness to; affirm; declare, esp. under oath in court.

2. to be evidence of; indicate.

3. [archaic] to profess or proclaim publicly.

Let me offer some possible examples:

His countenance testified exuberance.

Her eyes testify honesty.

Her kitchen testifies cleanliness.

His wounds testified carelessness.

His arms testify drug addiction.

His haircut testified blindness.

The top shelf in her bedroom testified the love of playing carnival games.

Her teeth testified the need for a can opener.

Her closet testified colorblindness.

Anchovies on the pizza testified a mis-delivery.

The Christmas gift of an anvil testified (something).

Etc.