parser/errors.py: check error message + error code for non-existent profiles

Add tests for passing the parser a file that doesn't exist, a symlink
to a file that doesn't exist, and a directory that contains that
latter.  Also include tests for different levels of -j passed as an
argument. These tests are based on the fixing commit 1259319508
("parser: Fix parser failing to handle errors when setting up work")

MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1070
Signed-off-by: Steve Beattie <steve.beattie@canonical.com>
Approved-by: John Johansen <john@jjmx.net>

parser/tst/errors.py

@@ -13,10 +13,13 @@
 #
 # ------------------------------------------------------------------
 
+import os
 import subprocess
 import sys
 import unittest
 from argparse import ArgumentParser
+from shutil import rmtree
+from tempfile import mkdtemp
 
 import testlib
 
@@ -28,6 +31,15 @@ class AAErrorTests(testlib.AATestTemplate):
         self.maxDiff = None
         self.cmd_prefix = [config.parser, '--config-file=./parser.conf', '-S', '-I', 'errors']
 
+        self.tmpdir = os.path.realpath(mkdtemp(prefix='test-aa-parser-errors-'))
+        self.profile_dir = os.path.join(self.tmpdir, 'profile')
+        os.mkdir(self.profile_dir)
+
+
+    def tearDown(self):
+        if os.path.exists(self.tmpdir):
+            rmtree(self.tmpdir)
+
     def _run_test(self, profile, message='', is_error=True):
         cmd = self.cmd_prefix + [profile]
 
@@ -90,6 +102,56 @@ class AAErrorTests(testlib.AATestTemplate):
             is_error=False
         )
 
+    def test_non_existant_profile(self):
+        test_profile = os.path.join(self.profile_dir, "does-not-exist.sd")
+        self._run_test(
+            test_profile,
+            "File {} not found, skipping...\n".format(test_profile),
+        )
+
+    # We can run this test with multiple different arguments
+    def _test_non_existant_symlink_target(self):
+        """Helper Function to test the parser on a symlink with a non-existent target"""
+
+        test_profile = os.path.join(self.profile_dir, "non-existant-target.sd")
+        os.symlink('does-not-exist.sd', test_profile)
+        self._run_test(
+            test_profile,
+            "File {} not found, skipping...\n".format(test_profile),
+        )
+
+    def test_non_existant_symlink_target(self):
+        '''Basic symlink test that goes nowhere'''
+        self._test_non_existant_symlink_target()
+
+    def test_non_existant_symlink_target_j0(self):
+        '''Basic symlink test that goes nowhere with 0 jobs'''
+        self.cmd_prefix.append('-j0')
+        self._test_non_existant_symlink_target()
+
+    def test_non_existant_symlink_target_j1(self):
+        '''Basic symlink test that goes nowhere with 1 job arg'''
+        self.cmd_prefix.append('-j1')
+        self._test_non_existant_symlink_target()
+
+    def test_non_existant_symlink_target_j8(self):
+        '''Basic symlink test that goes nowhere with 8 job arg'''
+        self.cmd_prefix.append('-j8')
+        self._test_non_existant_symlink_target()
+
+    def test_non_existant_symlink_target_jauto(self):
+        '''Basic symlink test that goes nowhere with auto job arg'''
+        self.cmd_prefix.append('-jauto')
+        self._test_non_existant_symlink_target()
+
+    def test_non_existant_symlink_target_in_directory(self):
+        '''Symlink test passing a directory to the parser'''
+        test_profile = os.path.join(self.profile_dir, "non-existant-target.sd")
+        os.symlink('does-not-exist.sd', test_profile)
+        self._run_test(
+            self.profile_dir,
+            "There was an error while loading profiles from {}\n".format(self.profile_dir),
+        )
 
 def main():
     global config