Index: utils/lit/tests/boolean-parsing.py
===================================================================
--- utils/lit/tests/boolean-parsing.py
+++ utils/lit/tests/boolean-parsing.py
@@ -1,4 +1,4 @@
 # Test the boolean expression parser
 # used for REQUIRES and UNSUPPORTED and XFAIL
 
-# RUN: %{python} -m lit.BooleanExpression
+# RUN: '%{python}' -m lit.BooleanExpression
Index: utils/lit/tests/discovery.py
===================================================================
--- utils/lit/tests/discovery.py
+++ utils/lit/tests/discovery.py
@@ -26,7 +26,7 @@
 # CHECK-BASIC-OUT: top-level-suite :: test-two
 
 # Check discovery when providing the special builtin 'config_map'
-# RUN: %{python} %{inputs}/config-map-discovery/driver.py \
+# RUN: '%{python}' %{inputs}/config-map-discovery/driver.py \
 # RUN:           %{inputs}/config-map-discovery/main-config/lit.cfg \
 # RUN:           %{inputs}/config-map-discovery/lit.alt.cfg \
 # RUN:           --single-process --debug --show-tests --show-suites > %t.out 2> %t.err
Index: utils/lit/tests/lit.cfg
===================================================================
--- utils/lit/tests/lit.cfg
+++ utils/lit/tests/lit.cfg
@@ -38,7 +38,7 @@
 config.substitutions.append(('%{src_root}', src_root))
 config.substitutions.append(('%{inputs}', os.path.join(
             src_root, 'tests', 'Inputs')))
-config.substitutions.append(('%{lit}', "%%{python} %s" % (
+config.substitutions.append(('%{lit}', "\'%%{python}\' %s" % (
             os.path.join(lit_path, 'lit.py'),)))
 config.substitutions.append(('%{python}', sys.executable))
 
Index: utils/lit/tests/shell-parsing.py
===================================================================
--- utils/lit/tests/shell-parsing.py
+++ utils/lit/tests/shell-parsing.py
@@ -1,3 +1,3 @@
 # Just run the ShUtil unit tests.
 #
-# RUN: %{python} -m lit.ShUtil
+# RUN: '%{python}' -m lit.ShUtil
Index: utils/lit/tests/unittest-adaptor.py
===================================================================
--- utils/lit/tests/unittest-adaptor.py
+++ utils/lit/tests/unittest-adaptor.py
@@ -1,6 +1,6 @@
 # Check the lit adaption to run under unittest.
 #
-# RUN: %{python} %s %{inputs}/unittest-adaptor 2> %t.err
+# RUN: '%{python}' %s %{inputs}/unittest-adaptor 2> %t.err
 # RUN: FileCheck < %t.err %s
 #
 # CHECK-DAG: unittest-adaptor :: test-two.txt ... FAIL