os2: add read dir test

tests/core/os/os2/dir.odin

@@ -0,0 +1,26 @@
+package tests_core_os_os2
+
+import os "core:os/os2"
+import    "core:path/filepath"
+import    "core:slice"
+import    "core:testing"
+
+@(test)
+test_read_dir :: proc(t: ^testing.T) {
+	path := filepath.join({#directory, "../dir"})
+	defer delete(path)
+
+	fis, err := os.read_all_directory_by_path(path, context.allocator)
+	defer os.file_info_slice_delete(fis, context.allocator)
+
+	slice.sort_by_key(fis, proc(fi: os.File_Info) -> string { return fi.name })
+
+	testing.expect_value(t, err, nil)
+	testing.expect_value(t, len(fis), 2)
+
+	testing.expect_value(t, fis[0].name, "b.txt")
+	testing.expect_value(t, fis[0].type, os.File_Type.Regular)
+
+	testing.expect_value(t, fis[1].name, "sub")
+	testing.expect_value(t, fis[1].type, os.File_Type.Directory)
+}