The test does not compare correctly for validating the result.
Test code is, as
 169 int modEx = modifiersEx & refMask;
 177 assertEQ(modifiersEx, modEx, "invalid extended modifiers");

 modEx & modifiersEx are compared for validating result.

But actually,
modEx & refMask should be compared.

The test executes fine currently because,
for each scenario refMask & modifiersEx are exactly same.

We have to check if the particular mask bits are correctly set.

for example,
When calling runScenario() line number 220
If we add InputEvent.ALT_DOWN_MASK in the second argument in addition to previous masks.
The test still passes, where as it should fail.