add windows exceptions to file permissions for files tests

packages/files/_test.pony

@@ -386,8 +386,16 @@ class iso _TestFileCreateDirNotWriteable is _NonRootTest
       try
         let file_path = dir_path.join("trycreateme")?
         let file = File(file_path)
-        h.assert_false(file.valid())
         h.assert_true(file.writeable)
+
+        ifdef windows then
+          // assuming that on windows opening is fine
+          // but on writing it will fail
+          h.assert_true(file.valid())
+          h.assert_false(file.write("oh noes!"))
+        end
+
+        h.assert_false(file.valid())
         h.assert_is[FileErrNo](file.errno(), FilePermissionDenied)
       then
         mode.owner_write = true
@@ -498,27 +506,31 @@ class _TestFileOpenWrite is UnitTest
 class iso _TestFileOpenPermissionDenied is _NonRootTest
   fun name(): String => "files/File.open-permission-denied"
   fun apply_as_non_root(h: TestHelper) =>
-    try
-      let filepath = FilePath(h.env.root as AmbientAuth, "tmp.open-not-readable")?
-      with file = CreateFile(filepath) as File do
-        file.print("unreadable")
+    ifdef not windows then
+      // on windows all files are always writeable
+      // with chmod there is no way to make a file not readable
+      try
+        let filepath = FilePath(h.env.root as AmbientAuth, "tmp.open-not-readable")?
+        with file = CreateFile(filepath) as File do
+          file.print("unreadable")
+        end
+        let mode: FileMode ref = FileMode.>private()
+        mode.owner_read = false
+        mode.owner_write = false
+        h.assert_true(filepath.chmod(mode))
+        let opened = File.open(filepath)
+        h.assert_true(opened.errno() is FilePermissionDenied)
+        h.assert_false(opened.valid())
+        let read = opened.read(10)
+        h.assert_eq[USize](read.size(), 0)
+
+        mode.owner_read = true
+        mode.owner_write = true
+        filepath.chmod(mode)
+        filepath.remove()
+      else
+        h.fail("Unhandled error!")
       end
-      let mode: FileMode ref = FileMode.>private()
-      mode.owner_read = false
-      mode.owner_write = false
-      h.assert_true(filepath.chmod(mode))
-      let opened = File.open(filepath)
-      h.assert_true(opened.errno() is FilePermissionDenied)
-      h.assert_false(opened.valid())
-      let read = opened.read(10)
-      h.assert_eq[USize](read.size(), 0)
-
-      mode.owner_read = true
-      mode.owner_write = true
-      filepath.chmod(mode)
-      filepath.remove()
-    else
-      h.fail("Unhandled error!")
     end