Determines whether the binding automatically registers testTextInput as a fake keyboard implementation.
Unit tests make use of this to mock out text input communication for widgets. An integration test would set this to false, to test real IME or keyboard input.
TestTextInput.isRegistered reports whether the text input mock is registered or not.
Some of the properties and methods on testTextInput are only valid if registerTestTextInput returns true when a test starts. If those members are accessed when using a binding that sets this flag to false, they will throw.
If this property returns true when a test ends, the testTextInput is unregistered.
This property should not change the value it returns during the lifetime of the binding. Changing the value of this property risks very confusing behavior as the TestTextInput may be inconsistently registered or unregistered.
bool get registerTestTextInput => true;