get_owner: handle non-existing path

Author: scivision

+stdlib/get_owner.m

@@ -1,5 +1,9 @@
 %% GET_OWNER owner of file or directory
-
+%
+%%% Inputs
+% * p: path to examine
+%%% Outputs
+% * n: owner, or empty if path does not exist
 function n = get_owner(p)
 arguments
   p (1,1) string
@@ -8,6 +12,9 @@
 % https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/nio/file/Files.html#getOwner(java.nio.file.Path,java.nio.file.LinkOption...)
 % https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/nio/file/LinkOption.html
 
+n = "";
+if ~stdlib.exists(p), return, end
+
 op = javaPathObject(p);
 opt = javaLinkOption();
 
@@ -20,3 +27,4 @@
 end
 
 %!assert(!isempty(get_owner(pwd)))
+%!assert(isempty(get_owner(tempname)))

test/TestJava.m

@@ -20,8 +20,11 @@ function test_filesystem_type(tc)
 
 function test_owner(tc)
 owner = stdlib.get_owner('.');
-L = strlength(owner);
-tc.verifyGreaterThan(L, 0, "expected non-empty username")
+tc.verifyGreaterThan(strlength(owner), 0, "expected non-empty username")
+
+owner = stdlib.get_owner(tempname);
+tc.verifyEqual(strlength(owner), 0, "expected empty owner")
+
 end