pytest: document new NayDuck features (#5294)

Co-authored-by: Bowen Wang <[email protected]>

nightly/README.md

@@ -70,12 +70,13 @@ As mentioned, there are additional arguments that can go between the
 test category and the test specification arguments.  Those are
 `--timeout`, `--release` and `--remote`.
 
-`--timeout=<timeout>` which specifies the timeout in seconds after
-which the test will be stopped.  If not given the default timeout is
-180 seconds (i.e. three minutes).  For example, the following
-increases timeout for a test to four minutes:
+`--timeout=<timeout>` which specifies the time after which the test
+will be stopped and considered failed.  `<timeout>` is an integer with
+an optional `s`, `m` or `h` suffix.  If no suffix is given, `s` is
+assumed.  The default timeout is three minutes.  For example, the
+following increases timeout for a test to four minutes:
 
-    pytest --timeout=240 sanity/restaked.py
+    pytest --timeout=4m sanity/restaked.py
 
 `--release` makes the build use a release profile rather than a dev
 profile.  In other words, all `cargo` invocations are passed

pytest/README.md

@@ -168,10 +168,13 @@ scheduled with `--release` flag) just as if they were executed on
 local machine.  Similarly, freshly built NEAR test contracts will be
 located in `../runtime/near-test-contracts/res` directory.
 
-The `NAYDUCK` and `NIGHTLY_RUNNER` environment variables are set when
-tests are run on NayDuck.  If all else fails they can be used to
+The `NAYDUCK=1`, `NIGHTLY_RUNNER=1` and `NAYDUCK_TIMEOUT=<timeout>`
+environment variables are set when tests are run on NayDuck.  If
+necessary and no other option exists, the first two can be used to
 change test’s behaviour to accommodate it running on the testing
-infrastructure as opposed to local machine.
+infrastructure as opposed to local machine.  Meanwhile,
+`NAYDUCK_TIMEOUT` specifies how much time in seconds test has to run
+before NayDuck decides the test failed.
 
 ### Code Style