Some missing tests:

1) g/./s^@^@	- okay: NULs in commands

2) g/./s/^@/	- okay: NULs in patterns

3) ed -x 	- verify: 8-bit clean

4) ed		- verify: long-line support

5) ed		- verify: interactive/help mode

6) G/pat/	- verify: global interactive command

7) V/pat/	- verify: global interactive command