filesystem_type: use missing

Author: scivision

+stdlib/+dotnet/filesystem_type.m

@@ -3,7 +3,7 @@
 function t = filesystem_type(file)
 
 
-t = '';
+t = missing;
 % Windows needs exists() not just strempty()
 if ~stdlib.exists(file)
   return

+stdlib/+java/filesystem_type.m

@@ -3,7 +3,7 @@
 
 function t = filesystem_type(file)
 
-t = '';
+t = missing;
 if stdlib.strempty(file)
   return
 end

+stdlib/+python/filesystem_type.m

@@ -1,6 +1,6 @@
 function t = filesystem_type(file)
 
-t = '';
+t = missing;
 
 try
 % important for heuristic matching

+stdlib/+shell/filesystem_type.m

@@ -1,6 +1,6 @@
 function [t, cmd] = filesystem_type(file)
 
-t = '';
+t = missing;
 
 if ispc()
   cmd = sprintf('pwsh -c ([System.IO.DriveInfo][System.IO.Path]::GetFullPath(''%s'')).DriveFormat', file);

+stdlib/filesystem_type.m

@@ -15,7 +15,7 @@
   backend (1,:) string = ["java", "dotnet", "python", "shell"]
 end
 
-r = '';
+r = missing;
 
 for b = backend
   switch b
@@ -33,7 +33,7 @@
       error('stdlib:filesystem_type:ValueError', 'Unknown backend: %s', b)
   end
 
-  if ~isempty(r)
+  if ~ismissing(r)
     return
   end
 end

test/TestDisk.m

@@ -121,18 +121,17 @@ function test_hard_link_count(tc, B_jps)
 function test_filesystem_type(tc, Ps, B_jdps)
 [t, b] = stdlib.filesystem_type(Ps, B_jdps);
 tc.assertMatches(b, B_jdps)
-tc.verifyClass(t, 'char')
 
 if ismember(B_jdps, stdlib.Backend().select('filesystem_type'))
   if ~stdlib.exists(Ps)
-    tc.verifyEmpty(t)
+    tc.verifyEqual(t, missing)
   else
-    tc.assumeFalse(isempty(t) && tc.CI, 'Some CI block viewing their filesystem type')
-    tc.assertNotEmpty(t)
+    tc.verifyClass(t, 'char')
+    tc.assumeFalse(any(ismissing(t)) && tc.CI, 'Some CI block viewing their filesystem type')
     tc.verifyGreaterThan(strlength(t), 0)
   end
 else
-  tc.verifyEmpty(t)
+  tc.verifyEqual(t, missing)
 end
 end