Add test case for an archive that contains two files of the same name.

regress/Makefile.am

diff --git a/regress/Makefile.am b/regress/Makefile.am
index 7bac8cc..61ac8ac 100644
--- a/regress/Makefile.am
+++ b/regress/Makefile.am
@@ -20,6 +20,7 @@
 	bigzero-zip.zip \
 	broken.zip \
 	encrypt.zip \
+	filename_duplicate.zip \
 	filename_empty.zip \
 	fileorder.zip \
 	firstsecond.zip \
@@ -130,6 +131,7 @@
 	encoding-cp437.test \
 	encoding-cp437-all.test \
 	encoding-utf-8.test \
+	open_filename_duplicate.test \
 	open_incons.test \
 	torrent-new.test
 

regress/filename_duplicate.zip

diff --git a/regress/filename_duplicate.zip b/regress/filename_duplicate.zip
new file mode 100644
index 0000000..96a11e7
--- /dev/null
+++ b/regress/filename_duplicate.zip
Binary files differ

regress/open_filename_duplicate.test

diff --git a/regress/open_filename_duplicate.test b/regress/open_filename_duplicate.test
new file mode 100644
index 0000000..acfacf0
--- /dev/null
+++ b/regress/open_filename_duplicate.test
@@ -0,0 +1,6 @@
+# zip_open: file opens fine even though same file name appears twice
+program tryopen
+args filename_duplicate.zip
+return 0
+file filename_duplicate.zip filename_duplicate.zip filename_duplicate.zip
+stdout opening `filename_duplicate.zip' succeeded, 2 entries