If only approximate testing of the strength of cordage is required, then you can make your own test rig fairly easily.

Obtain a short length of substantial RSJ or timber, and support each end of this on a small pier or column of bricks or concrete blocks.

Attach the sample to be tested to this support, and attach weights to the sample until it fails.

To avoid danger from the end of the tested cord whipping around, or from the weights falling, arange such that the weight will only fall an inch or so.

A suitable weight up to about a ton is an IBC of known empty weight. Suspend this from the sample, and fill with water from a safe distance by use of a garden hose.
Either measure the volume of water added by a water meter, or use a container with markings as to volume.

With a little ingenuity, other methods can be devised. Use of a water container that can be emptied or filled remotely has much to commend it as no close approach during testing is needed.