binman: Allow preserving test directories

Sometimes when debugging tests it is useful to keep the input and output
directories so they can be examined later. Add an option for this and
update the binman tests to support it. This affects both the test class
and the tearDown() function called after each test.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/binman/README

@@ -731,6 +731,14 @@ Use '-P 1' to disable this. It is automatically disabled when code coverage is
 being used (-T) since they are incompatible.
 
 
+Debugging tests
+---------------
+
+Sometimes when debugging tests it is useful to keep the input and output
+directories so they can be examined later. Use -X or --test-preserve-dirs for
+this.
+
+
 Advanced Features / Technical docs
 ----------------------------------
 

tools/binman/binman.py

@@ -46,15 +46,20 @@ except:
 import control
 import test_util
 
-def RunTests(debug, verbosity, processes, args):
+def RunTests(debug, verbosity, processes, test_preserve_dirs, args):
     """Run the functional tests and any embedded doctests
 
     Args:
         debug: True to enable debugging, which shows a full stack trace on error
         verbosity: Verbosity level to use
+        test_preserve_dirs: True to preserve the input directory used by tests
+            so that it can be examined afterwards (only useful for debugging
+            tests). If a single test is selected (in args[0]) it also preserves
+            the output directory for this test. Both directories are displayed
+            on the command line.
+        processes: Number of processes to use to run tests (None=same as #CPUs)
         args: List of positional args provided to binman. This can hold a test
             name to execute (as in 'binman -t testSections', for example)
-        processes: Number of processes to use to run tests (None=same as #CPUs)
     """
     import elf_test
     import entry_test
@@ -82,6 +87,11 @@ def RunTests(debug, verbosity, processes, args):
     loader = unittest.TestLoader()
     for module in (entry_test.TestEntry, ftest.TestFunctional, fdt_test.TestFdt,
                    elf_test.TestElf, image_test.TestImage):
+        # Test the test module about our arguments, if it is interested
+        if hasattr(module, 'setup_test_args'):
+            setup_test_args = getattr(module, 'setup_test_args')
+            setup_test_args(preserve_indir=test_preserve_dirs,
+                preserve_outdirs=test_preserve_dirs and test_name is not None)
         if test_name:
             try:
                 suite.addTests(loader.loadTestsFromName(test_name, module))
@@ -157,7 +167,7 @@ def RunBinman(options, args):
 
     if options.test:
         ret_code = RunTests(options.debug, options.verbosity, options.processes,
-                            args[1:])
+                            options.test_preserve_dirs, args[1:])
 
     elif options.test_coverage:
         RunTestCoverage()

tools/binman/cmdline.py

@@ -59,6 +59,10 @@ def ParseArgs(argv):
     parser.add_option('-v', '--verbosity', default=1,
         type='int', help='Control verbosity: 0=silent, 1=progress, 3=full, '
         '4=debug')
+    parser.add_option('-X', '--test-preserve-dirs', action='store_true',
+        help='Preserve and display test-created input directories; also '
+             'preserve the output directory if a single test is run (pass test '
+             'name at the end of the command line')
 
     parser.usage += """
 

tools/binman/ftest.py

@@ -6,6 +6,8 @@
 #
 #    python -m unittest func_test.TestFunctional.testHelp
 
+from __future__ import print_function
+
 import hashlib
 from optparse import OptionParser
 import os
@@ -134,10 +136,27 @@ class TestFunctional(unittest.TestCase):
     @classmethod
     def tearDownClass(self):
         """Remove the temporary input directory and its contents"""
-        if self._indir:
-            shutil.rmtree(self._indir)
+        if self.preserve_indir:
+            print('Preserving input dir: %s' % self._indir)
+        else:
+            if self._indir:
+                shutil.rmtree(self._indir)
         self._indir = None
 
+    @classmethod
+    def setup_test_args(cls, preserve_indir=False, preserve_outdirs=False):
+        """Accept arguments controlling test execution
+
+        Args:
+            preserve_indir: Preserve the shared input directory used by all
+                tests in this class.
+            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.
+        """
+        cls.preserve_indir = preserve_indir
+        cls.preserve_outdirs = preserve_outdirs
+
     def setUp(self):
         # Enable this to turn on debugging output
         # tout.Init(tout.DEBUG)
@@ -145,7 +164,10 @@ class TestFunctional(unittest.TestCase):
 
     def tearDown(self):
         """Remove the temporary output directory"""
-        tools._FinaliseForTest()
+        if self.preserve_outdirs:
+            print('Preserving output dir: %s' % tools.outdir)
+        else:
+            tools._FinaliseForTest()
 
     @classmethod
     def _ResetDtbs(self):