Index: test/dosep.py
===================================================================
--- test/dosep.py
+++ test/dosep.py
@@ -148,7 +148,9 @@
     return (timed_out, failed, passed)
 
 def main():
-    test_root = sys.path[0]
+    # We can't use sys.path[0] to determine the script directory
+    # because it doesn't work under a debugger
+    test_root = os.path.dirname(os.path.realpath(__file__))
 
     parser = OptionParser(usage="""\
 Run lldb test suite using a separate process for each test file.
Index: test/dotest.py
===================================================================
--- test/dotest.py
+++ test/dotest.py
@@ -253,7 +253,9 @@
 progress_bar = False
 
 # By default, search from the script directory.
-testdirs = [ sys.path[0] ]
+# We can't use sys.path[0] to determine the script directory
+# because it doesn't work under a debugger
+testdirs = [ os.path.dirname(os.path.realpath(__file__)) ]
 
 # Separator string.
 separator = '-' * 70
@@ -364,6 +366,7 @@
 o GDB_REMOTE_LOG: if defined, specifies the log file pathname for the
   'process.gdb-remote' subsystem with a default option of 'packets' if
   GDB_REMOTE_LOG_OPTION is not defined.
+
 """
     sys.exit(0)
 
@@ -922,10 +925,10 @@
     global lldbExecutablePath
 
     # Get the directory containing the current script.
-    if ("DOTEST_PROFILE" in os.environ or "DOTEST_PDB" in os.environ) and "DOTEST_SCRIPT_DIR" in os.environ:
+    if "DOTEST_PROFILE" in os.environ and "DOTEST_SCRIPT_DIR" in os.environ:
         scriptPath = os.environ["DOTEST_SCRIPT_DIR"]
     else:
-        scriptPath = sys.path[0]
+        scriptPath = os.path.dirname(os.path.realpath(__file__))
     if not scriptPath.endswith('test'):
         print "This script expects to reside in lldb's test directory."
         sys.exit(-1)
@@ -944,7 +947,7 @@
 
     # Set up the LLDB_SRC environment variable, so that the tests can locate
     # the LLDB source code.
-    os.environ["LLDB_SRC"] = os.path.join(sys.path[0], os.pardir)
+    os.environ["LLDB_SRC"] = os.path.join(scriptPath, os.pardir)
 
     pluginPath = os.path.join(scriptPath, 'plugins')
     pexpectPath = os.path.join(scriptPath, 'pexpect-2.4')