When cameras were mainly mechanical devices the focus was on the handling and the engineering precision characteristics, because the additional two defining components for the image quality (the lens and the film) were in a separate category.
Cameras are now electronic devices with integrated imaging sensors and the test characteristics have changed quite a lot. It is usually the case that a test has to include a lens because that is the only way to test the sensor of the camera. In addition you cannot look at the image file as one did with film when the negative was a separate element. Now the image file has to be processed by a computer program. And there is always the problem that there is an unknown component in the imaging chain: the in-camera pre-processing.
In the AgX days there were three quite independent components in the imaging chain: the camera precious engineering, the emulsion/developer and the lens. Any one of these components could be held constant and the other variables be studied.
In the CMOS/CCD days there is a much more complex and integrated imaging chain That is very difficult to separate and therefore meaningful statements can only be made about the whole package, not the individual components. A so-called camera test is now a test of the imaging chain and the expertise of the user who handles the camera.