diff --git a/lldb/packages/Python/lldbsuite/test/decorators.py b/lldb/packages/Python/lldbsuite/test/decorators.py
--- a/lldb/packages/Python/lldbsuite/test/decorators.py
+++ b/lldb/packages/Python/lldbsuite/test/decorators.py
@@ -375,14 +375,18 @@
 def debugserver_test(func):
     """Decorate the item as a debugserver test."""
     def should_skip_debugserver_test():
-        return "debugserver tests" if configuration.dont_do_debugserver_test else None
+        return ("debugserver tests"
+                if not configuration.debugserver_platform
+                else None)
     return skipTestIfFn(should_skip_debugserver_test)(func)
 
 
 def llgs_test(func):
     """Decorate the item as a lldb-server test."""
     def should_skip_llgs_tests():
-        return "llgs tests" if configuration.dont_do_llgs_test else None
+        return ("llgs tests"
+                if not configuration.llgs_platform
+                else None)
     return skipTestIfFn(should_skip_llgs_tests)(func)
 
 
diff --git a/lldb/packages/Python/lldbsuite/test/dotest.py b/lldb/packages/Python/lldbsuite/test/dotest.py
--- a/lldb/packages/Python/lldbsuite/test/dotest.py
+++ b/lldb/packages/Python/lldbsuite/test/dotest.py
@@ -938,26 +938,20 @@
     # Note that it's not dotest's job to clean this directory.
     lldbutil.mkdir_p(configuration.test_build_dir)
 
-    target_platform = lldb.selected_platform.GetTriple().split('-')[2]
+    from . import lldbplatformutil
+    target_platform = lldbplatformutil.getPlatform()
 
     checkLibcxxSupport()
     checkLibstdcxxSupport()
     checkWatchpointSupport()
     checkDebugInfoSupport()
 
-    # Don't do debugserver tests on anything except OS X.
-    configuration.dont_do_debugserver_test = (
-            "linux" in target_platform or
-            "freebsd" in target_platform or
-            "netbsd" in target_platform or
-            "windows" in target_platform)
-
-    # Don't do lldb-server (llgs) tests on platforms not supporting it.
-    configuration.dont_do_llgs_test = not (
-            "freebsd" in target_platform or
-            "linux" in target_platform or
-            "netbsd" in target_platform or
-            "windows" in target_platform)
+    # Perform LLGS tests only on platforms using it.
+    configuration.llgs_platform = (
+        target_platform in ["freebsd", "linux", "netbsd", "windows"])
+
+    # Perform debugserver tests elsewhere (i.e. on Darwin platforms).
+    configuration.debugserver_platform = not configuration.llgs_platform
 
     for testdir in configuration.testdirs:
         for (dirpath, dirnames, filenames) in os.walk(testdir):