Index: lldb/test/API/lldbtest.py
===================================================================
--- lldb/test/API/lldbtest.py
+++ lldb/test/API/lldbtest.py
@@ -29,6 +29,39 @@
     if not os.path.isdir(path):
         raise OSError(errno.ENOTDIR, "%s is not a directory"%path)
 
+# On macOS, we can't do the DYLD_INSERT_LIBRARIES trick with a shim
+# python binary as the ASan interceptors get loaded too late. Also,
+# when SIP is enabled, we can't inject libraries into system binaries
+# at all, so we need a copy of the "real" python to work with.
+def get_darwin_python_interpreter(builddir, executable):
+    # Avoid doing any work if we already copied the binary.
+    copied_python = os.path.join(builddir, 'copied-python')
+    if os.path.isfile(copied_python):
+        return copied_python
+
+    # Find the "real" python binary.
+    import shutil, subprocess
+    real_python = subprocess.check_output([
+        executable,
+        os.path.join(os.path.dirname(os.path.realpath(__file__)),
+            'get_darwin_real_python.py')
+    ]).decode('utf-8').strip()
+
+    # Copy over the real python.
+    shutil.copy(real_python, copied_python)
+
+    # Now make sure the copied Python works. The Python in Xcode has a relative
+    # RPATH and cannot be copied.
+    try:
+        # We don't care about the output.
+        subprocess.check_output([copied_python, '-V'], stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError:
+        os.remove(copied_python)
+        return real_python
+
+    return copied_python
+
+
 class LLDBTest(TestFormat):
     def __init__(self, dotest_cmd):
         self.dotest_cmd = dotest_cmd
@@ -75,25 +108,9 @@
 
         builddir = getBuildDir(cmd)
         mkdir_p(builddir)
-
-        # On macOS, we can't do the DYLD_INSERT_LIBRARIES trick with a shim
-        # python binary as the ASan interceptors get loaded too late. Also,
-        # when SIP is enabled, we can't inject libraries into system binaries
-        # at all, so we need a copy of the "real" python to work with.
-        #
-        # Find the "real" python binary, copy it, and invoke it.
         if 'DYLD_INSERT_LIBRARIES' in test.config.environment and \
                 platform.system() == 'Darwin':
-            copied_python = os.path.join(builddir, 'copied-system-python')
-            if not os.path.isfile(copied_python):
-                import shutil, subprocess
-                python = subprocess.check_output([
-                    executable,
-                    os.path.join(os.path.dirname(os.path.realpath(__file__)),
-                        'get_darwin_real_python.py')
-                ]).decode('utf-8').strip()
-                shutil.copy(python, copied_python)
-            cmd[0] = copied_python
+            cmd[0] = get_darwin_python_interpreter(builddir, executable)
 
         if 'lldb-repro-capture' in test.config.available_features or \
            'lldb-repro-replay' in test.config.available_features: