readme: document --no-quit-on-fail

README.adoc

@@ -11964,9 +11964,9 @@ The link:test[] script runs several different types of tests, which can also be
 
 link:test[] does not all possible tests, because there are too many possible variations and that would take forever. The rationale is the same as for `./build all` and is explained in `./build --help`.
 
-See the sources of those test scripts to learn how to run more specialized tests.
+===== Test arch and emulator selection
 
-One important tip is that you can select multiple archs and emulators of interest with any command as in:
+You can select multiple archs and emulators of interest, as for an other command, with:
 
 ....
 ./test-user-mode \
@@ -11977,10 +11977,31 @@ One important tip is that you can select multiple archs and emulators of interes
 ;
 ....
 
+You can also test all supported archs and emulators with:
+
+....
+./test-user-mode \
+  --all-archs \
+  --all-emulators \
+;
+....
+
 This command would run the test four times, using `x86_64` and `aarch64` with both gem5 and QEMU.
 
 Without those flags, it defaults to just running the default arch and emulator once: `x86_64` and `qemu`.
 
+===== Quit on fail
+
+By default, tests stop running as soon as the first failure happens.
+
+You can prevent this with the `--no-quit-on-fail option, e.g.:
+
+....
+./test-user-mode --no-quit-on-fail
+....
+
+You can then see which tests failed on the test summary report at the end.
+
 ===== Test userland in full system
 
 Run all userland tests from inside full system simulation (i.e. not <<user-mode-simulation>>):