[libc++][WIP] Move the libc++ test format to Lit

This allows the generally-useful parts of the test format to be
shipped alongside Lit, which would make it usable for third-party
developers as well. This came up at C++Now in the context of the
Beman project where we'd like to set up a non-LLVM project that can
use the same testing framework as libc++.

With the test format moved to Lit, the format would be available
after installing Lit with pip, which is really convenient.

Author: ldionne

libcxx/test/configs/cmake-bridge.cfg.in

@@ -18,7 +18,7 @@ import libcxx.test.format
 # Basic configuration of the test suite
 config.name = os.path.basename('@LIBCXX_TEST_CONFIG@')
 config.test_source_root = os.path.join('@LIBCXX_SOURCE_DIR@', 'test')
-config.test_format = libcxx.test.format.CxxStandardLibraryTest()
+config.test_format = libcxx.test.format.LibcxxTest()
 config.recursiveExpansionLimit = 10
 config.test_exec_root = os.path.join('@CMAKE_BINARY_DIR@', 'test')
 

libcxx/utils/libcxx/test/dsl.py

@@ -99,7 +99,7 @@ def _executeWithFakeConfig(test, commands):
         order="smart",
         params={},
     )
-    return libcxx.test.format._executeScriptInternal(test, litConfig, commands)
+    return lit.formats.standardlibrarytest._executeScriptInternal(test, litConfig, commands)
 
 
 def _makeConfigTest(config):
@@ -121,12 +121,12 @@ def _makeConfigTest(config):
 
     class TestWrapper(lit.Test.Test):
         def __enter__(self):
-            testDir, _ = libcxx.test.format._getTempPaths(self)
+            testDir, _ = lit.formats.standardlibrarytest._getTempPaths(self)
             os.makedirs(testDir)
             return self
 
         def __exit__(self, *args):
-            testDir, _ = libcxx.test.format._getTempPaths(self)
+            testDir, _ = lit.formats.standardlibrarytest._getTempPaths(self)
             shutil.rmtree(testDir)
             os.remove(tmp.name)