unset COMMIT_AUTHOR_NAME
 unset GIT_ALTERNATE_OBJECT_DIRECTORIES
 unset GIT_AUTHOR_DATE
-unset GIT_AUTHOR_EMAIL
-unset GIT_AUTHOR_NAME
+GIT_AUTHOR_EMAIL=author@example.com
+GIT_AUTHOR_NAME='A U Thor'
 unset GIT_COMMITTER_DATE
-unset GIT_COMMITTER_EMAIL
-unset GIT_COMMITTER_NAME
+GIT_COMMITTER_EMAIL=committer@example.com
+GIT_COMMITTER_NAME='C O Mitter'
 unset GIT_DIFF_OPTS
 unset GIT_DIR
 unset GIT_EXTERNAL_DIFF
 unset GIT_OBJECT_DIRECTORY
 unset SHA1_FILE_DIRECTORIES
 unset SHA1_FILE_DIRECTORY
+export GIT_AUTHOR_EMAIL GIT_AUTHOR_NAME
+export GIT_COMMITTER_EMAIL GIT_COMMITTER_NAME
 
 # Each test should start with something like this, after copyright notices:
 #