patman: Support extra test features

Provide support for the -X flag, which preserves the working directory
used by tests. Also support -N which shows captured output for tests.

Finally, allow selection of a particular test to run.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/func_test.py b/tools/patman/func_test.py
index 161b5ad..85e7b47 100644
--- a/tools/patman/func_test.py
+++ b/tools/patman/func_test.py
@@ -53,6 +53,25 @@
     mary = 'Mary Bloggs <mary@napierwallies.co.nz>'
     commits = None
     patches = None
+    verbosity = False
+    preserve_outdirs = False
+
+    @classmethod
+    def setup_test_args(cls, preserve_indir=False, preserve_outdirs=False,
+                        toolpath=None, verbosity=None, no_capture=False):
+        """Accept arguments controlling test execution
+
+        Args:
+            preserve_indir: not used
+            preserve_outdir: Preserve the output directories used by tests.
+                Each test has its own, so this is normally only useful when
+                running a single test.
+            toolpath: not used
+        """
+        cls.preserve_outdirs = preserve_outdirs
+        cls.toolpath = toolpath
+        cls.verbosity = verbosity
+        cls.no_capture = no_capture
 
     def setUp(self):
         self.tmpdir = tempfile.mkdtemp(prefix='patman.')
@@ -60,7 +79,10 @@
         self.repo = None
 
     def tearDown(self):
-        shutil.rmtree(self.tmpdir)
+        if self.preserve_outdirs:
+            print(f'Output dir: {self.tmpdir}')
+        else:
+            shutil.rmtree(self.tmpdir)
         terminal.set_print_test_mode(False)
 
     @staticmethod