Be explicit that fd are used only a Archive creation.

Close opened file descriptor in test before checking equivalence.

include/zim/archive.h

@@ -97,6 +97,8 @@ namespace zim
       /** Archive constructor.
        *
        *  Construct an archive from a file descriptor.
+       *  Fd is used only at Archive creation.
+       *  Ownership of the fd is not taken and it must be closed by caller.
        *
        *  Note: This function is not available under Windows.
        *
@@ -108,6 +110,8 @@ namespace zim
        *
        *  Construct an archive from a descriptor of a file with an embedded ZIM
        *  archive inside.
+       *  Fd is used only at Archive creation.
+       *  Ownership of the fd is not taken and it must be closed by caller.
        *
        *  Note: This function is not available under Windows.
        *
@@ -120,6 +124,8 @@ namespace zim
        *
        *  Construct an archive from several file descriptors.
        *  Each part may be embedded in a file.
+       *  Fds are used only at Archive creation.
+       *  Ownership of the fds is not taken and they must be closed by caller.
        *  Fds (int) can be the same between FdInput if the parts belong to the same file.
        *
        *  Note: This function is not available under Windows.

test/archive.cpp

@@ -625,6 +625,7 @@ TEST(ZimArchive, openZIMFileEmbeddedInAnotherFile)
     const zim::Archive archive1(normalZims[i].path);
     const int fd = OPEN_READ_ONLY(embeddedZims[i].path);
     const zim::Archive archive2(zim::FdInput(fd, 8, archive1.getFilesize()));
+    close(fd);
 
     checkEquivalence(archive1, archive2);
   }
@@ -653,6 +654,10 @@ TEST(ZimArchive, openZIMFileMultiPartEmbeddedInAnotherFile)
 
     const zim::Archive archive2(fds);
 
+    for(auto &fd: fds) {
+      close(fd.fd);
+    }
+
     checkEquivalence(archive1, archive2);
   }
 }