This patch migrates tests so that they can be run concurrently.
- By default, tests still run in one thread.
- To run tests in 4 parallel threads, run node test/test.js -j 4 or npm run unit -- -j 4
- Environment variable PPTR_PARALLEL_TESTS could be set to override default parallelization
Every test gets passed in a state. State is set up in the beforeAll and beforeEach callbacks,
and should be teared down in the afterAll and afterEach callbacks.
By default, state has a parallelIndex variable initialized that defines the thread index that runs the execution.
This patch implements FrameManager which is responsible for maintaining
the frame tree. FrameManager is quite basic: it sends FrameAttached,
FrameDetached and FrameNavigated events, and can report mainFrame and
all frames.
The next step would be moving certain Page API's to the Frame. For
example, such method as Page.evaluate, Page.navigate and others should
be available on Frame object as well.
References #4
