Adapt to exit code 1 that "modify" now returns on errors.
diff --git a/regress/delete_invalid.test b/regress/delete_invalid.test
index e778c51..6cf34db 100644
--- a/regress/delete_invalid.test
+++ b/regress/delete_invalid.test
@@ -1,6 +1,6 @@
 # delete last entry in zip archive
 program modify
-return 0
+return 1
 args testfile.zzip delete 5
 file testfile.zzip testfile.zip testfile.zip
 stderr can't delete file at index `5': Invalid argument
diff --git a/regress/file_comment_encmismatch.test b/regress/file_comment_encmismatch.test
index 18fa655..845851e 100644
--- a/regress/file_comment_encmismatch.test
+++ b/regress/file_comment_encmismatch.test
@@ -1,6 +1,6 @@
 # set file comment to UTF-8 for CP437 encoded filename (fails)
 program modify
-return 0
+return 1
 args testfile file_comment 0 ÄÖÜßäöü
 file testfile test-cp437.zip test-cp437.zip
 stderr can't set file comment at index `0' to `ÄÖÜßäöü': Encoding of name and comment do not match
diff --git a/regress/rename_cp437.test b/regress/rename_cp437.test
index 6596afd..6865b7e 100644
--- a/regress/rename_cp437.test
+++ b/regress/rename_cp437.test
@@ -1,6 +1,6 @@
 # rename file to CP437 name in zip archive (fails)
 program modify
-return 0
+return 1
 args testfile.zip rename 0 ‚ƒ„…†‡ˆ‰Š‹ŒŽ
 file testfile.zip testfile.zip testfile.zip
 stderr can't rename file at index `0' to `‚ƒ„…†‡ˆ‰Š‹ŒŽ': Invalid argument
diff --git a/regress/rename_deleted.test b/regress/rename_deleted.test
index a5ae64b..c304b73 100644
--- a/regress/rename_deleted.test
+++ b/regress/rename_deleted.test
@@ -1,6 +1,6 @@
 # rename deleted entry in zip archive (fails)
 program modify
-return 0
+return 1
 args testfile.zip delete 1 delete 3 rename 1 othername
 file testfile.zip testcomment.zip testcomment13.zip
 stderr can't rename file at index `1' to `othername': Entry has been deleted
diff --git a/regress/rename_utf8_encmismatch.test b/regress/rename_utf8_encmismatch.test
index b45ff0f..60c44f4 100644
--- a/regress/rename_utf8_encmismatch.test
+++ b/regress/rename_utf8_encmismatch.test
@@ -1,6 +1,6 @@
 # rename file to UTF-8 name in zip archive with CP437 comment (fails)
 program modify
-return 0
+return 1
 args testfile rename 0 ÄÖÜßäöü
 file testfile test-cp437-fc.zip test-cp437-fc.zip
 stderr can't rename file at index `0' to `ÄÖÜßäöü': Encoding of name and comment do not match