[test] Skip a test when using an out-of-tree debugserver

The test "test_fp_special_purpose_register_read" in TestRegisters.py
fails on Darwin machines configured to use an out-of-tree debugserver.

The error message is: 'register read ftag' returns expected result, got
'ftag = 0x80'. This indicates that the debugserver in use is too old.

This commit introduces a decorator which can be used to skip tests which
rely on having a just-built debugserver. This resolves the issue:

$ ./bin/llvm-dotest -p TestRegisters.py -v
  1 out of 617 test suites processed - TestRegisters.py
  Test Methods:          7
  Success:               6
  Skip:                  1
...

llvm-svn: 327052

1 files changed, 1 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/register/register_command/TestRegisters.py b/lldb/packages/Python/lldbsuite/test/functionalities/register/register_command/TestRegisters.py
index f82443f9b15..b28e8c7915d 100644
--- a/lldb/packages/Python/lldbsuite/test/functionalities/register/register_command/TestRegisters.py
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/register/register_command/TestRegisters.py
@@ -69,6 +69,7 @@ class RegisterCommandsTestCase(TestBase):
     @expectedFailureAndroid(archs=["i386"])
     @skipIfFreeBSD  # llvm.org/pr25057
     @skipIf(archs=no_match(['amd64', 'i386', 'x86_64']))
+    @skipIfOutOfTreeDebugserver
     def test_fp_special_purpose_register_read(self):
         """Test commands that read fpu special purpose registers."""
         self.build()