Correct remove_target() call in TUTORIAL.md and test_tutorial.py

Target removal is done relative to the root of the targets dir.

Signed-off-by: Sebastien Awwad <[email protected]>

Author: awwad

docs/TUTORIAL.md

@@ -428,7 +428,7 @@ new metadata to disk.
 
 # Remove a target file listed in the "targets" metadata.  The target file is
 # not actually deleted from the file system.
->>> repository.targets.remove_target("repository/targets/file3.txt")
+>>> repository.targets.remove_target('file3.txt')
 
 # repository.writeall() writes any required metadata files (e.g., if
 # targets.json is updated, snapshot.json and timestamp.json are also written

tests/test_tutorial.py

@@ -9,7 +9,16 @@
 
 <Purpose>
   Regression test for the TUF tutorial as laid out in TUTORIAL.md.
-  This simply runs the tutorial and checks some results.
+  This essentially runs the tutorial and checks some results.
+
+  There are a few deviations from the TUTORIAL.md instructions:
+   - steps that involve user input (like passphrases) are modified slightly
+     to not require user input
+   - use of path separators '/' is replaced by join() calls. (We assume that
+     when following the tutorial, users will correctly deal with path
+     separators for their system if they happen to be using non-Linux systems.)
+   - shell instructions are mimicked using Python commands
+
 """
 
 # Help with Python 3 compatibility, where the print statement is a function, an
@@ -241,7 +250,7 @@ def test_tutorial(self):
 
     repository.writeall()
 
-    repository.targets.remove_target("repository/targets/file3.txt")
+    repository.targets.remove_target('file3.txt')
     self.assertTrue(os.path.exists(os.path.join(
         'repository','targets', 'file3.txt')))