The font for this test case has
an AAT Extended Glyph Metamorphosis Table
with a single Glyph Insertion Subtable. Its finite-state machine
contains two states (0 and 1) with the following transitions:
For glyph A
in state 0, the machine moves to state 1 while inserting
C after the current position.
This transition carries the DontAdvance flag.
in state 1, the machine moves to state 0 while inserting
B after the current position.
This transition carries no flags.
For glyphs B and C, the machine stays
in its current state while inserting E to the right of
the current position. This transition carries no flags.
For any other glyphs and “end of text”, the machine performs
no action.