oeqa/selftest/devtool: abort if a local workspace already exist

if user run devtool selftests with a local workspacelayer
the tests fail with various error such as:

- devtool.DevtoolAddTests.test_devtool_add just hangs
- devtool.DevtoolModifyTests.* fail with the following error:

 ERROR: Found duplicated BBFILE_COLLECTIONS 'workspacelayer', check bblayers.conf or layer.conf to fix it.
 Found duplicated BBFILE_COLLECTIONS 'workspacelayer', check bblayers.conf or layer.conf to fix it.

Check if a workspacelayer exists, warn the user and abort the tests

(From OE-Core rev: a74962cfb0485f6f2b9e2b751c33c8eafca8705a)

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/selftest/cases/devtool.py

@@ -27,6 +27,9 @@ def setUpModule():
     corecopydir = os.path.join(templayerdir, 'core-copy')
     bblayers_conf = os.path.join(os.environ['BUILDDIR'], 'conf', 'bblayers.conf')
     edited_layers = []
+    # make sure user doesn't have a local workspace
+    result = runCmd('bitbake-layers show-layers')
+    assert "workspacelayer" not in result.output, "Devtool test suite cannot be run with a local workspace directory"
 
     # We need to take a copy of the meta layer so we can modify it and not
     # have any races against other tests that might be running in parallel