diff --git a/tests/bootstrap_test.sh b/tests/bootstrap_test.sh
index d89e6b7..7925ab0 100755
--- a/tests/bootstrap_test.sh
+++ b/tests/bootstrap_test.sh
@@ -17,11 +17,11 @@
 function test_null_build() {
   setup
   run_soong
-  local bootstrap_mtime1=$(stat -c "%y" out/soong/bootstrap.ninja)
-  local output_mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r bootstrap_mtime1=$(stat -c "%y" out/soong/bootstrap.ninja)
+  local -r output_mtime1=$(stat -c "%y" out/soong/build.ninja)
   run_soong
-  local bootstrap_mtime2=$(stat -c "%y" out/soong/bootstrap.ninja)
-  local output_mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r bootstrap_mtime2=$(stat -c "%y" out/soong/bootstrap.ninja)
+  local -r output_mtime2=$(stat -c "%y" out/soong/build.ninja)
 
   if [[ "$bootstrap_mtime1" == "$bootstrap_mtime2" ]]; then
     # Bootstrapping is always done. It doesn't take a measurable amount of time.
@@ -36,12 +36,12 @@
 function test_soong_build_rebuilt_if_blueprint_changes() {
   setup
   run_soong
-  local mtime1=$(stat -c "%y" out/soong/bootstrap.ninja)
+  local -r mtime1=$(stat -c "%y" out/soong/bootstrap.ninja)
 
   sed -i 's/pluginGenSrcCmd/pluginGenSrcCmd2/g' build/blueprint/bootstrap/bootstrap.go
 
   run_soong
-  local mtime2=$(stat -c "%y" out/soong/bootstrap.ninja)
+  local -r mtime2=$(stat -c "%y" out/soong/bootstrap.ninja)
 
   if [[ "$mtime1" == "$mtime2" ]]; then
     fail "Bootstrap Ninja file did not change"
@@ -79,7 +79,7 @@
 function test_add_android_bp() {
   setup
   run_soong
-  local mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   mkdir -p a
   cat > a/Android.bp <<'EOF'
@@ -91,7 +91,7 @@
   touch a/my_little_binary_host.py
   run_soong
 
-  local mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$mtime1" == "$mtime2" ]]; then
     fail "Output Ninja file did not change"
   fi
@@ -142,7 +142,7 @@
 EOF
   touch a/my_little_binary_host.py
   run_soong
-  local ninja_mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r ninja_mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   local glob_deps_file=out/soong/globs/build/0.d
 
@@ -151,7 +151,7 @@
   fi
 
   run_soong
-  local ninja_mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r ninja_mtime2=$(stat -c "%y" out/soong/build.ninja)
 
   # There is an ineffiencency in glob that requires bpglob to rerun once for each glob to update
   # the entry in the .ninja_log.  It doesn't update the output file, but we can detect the rerun
@@ -160,15 +160,15 @@
     fail "Glob deps file missing after second build"
   fi
 
-  local glob_deps_mtime2=$(stat -c "%y" "$glob_deps_file")
+  local -r glob_deps_mtime2=$(stat -c "%y" "$glob_deps_file")
 
   if [[ "$ninja_mtime1" != "$ninja_mtime2" ]]; then
     fail "Ninja file rewritten on null incremental build"
   fi
 
   run_soong
-  local ninja_mtime3=$(stat -c "%y" out/soong/build.ninja)
-  local glob_deps_mtime3=$(stat -c "%y" "$glob_deps_file")
+  local -r ninja_mtime3=$(stat -c "%y" out/soong/build.ninja)
+  local -r glob_deps_mtime3=$(stat -c "%y" "$glob_deps_file")
 
   if [[ "$ninja_mtime2" != "$ninja_mtime3" ]]; then
     fail "Ninja file rewritten on null incremental build"
@@ -192,12 +192,12 @@
 EOF
   touch a/my_little_binary_host.py
   run_soong
-  local mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   touch a/my_little_library.py
   run_soong
 
-  local mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$mtime1" == "$mtime2" ]]; then
     fail "Output Ninja file did not change"
   fi
@@ -275,10 +275,10 @@
   run_soong
   grep -q "CHERRY IS RED" out/soong/build.ninja \
     || fail "second value of environment variable not used"
-  local mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   run_soong
-  local mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$mtime1" != "$mtime2" ]]; then
     fail "Output Ninja file changed when environment variable did not"
   fi
@@ -288,7 +288,7 @@
 function test_create_global_include_directory() {
   setup
   run_soong
-  local mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   # Soong needs to know if top level directories like hardware/ exist for use
   # as global include directories.  Make sure that doesn't cause regens for
@@ -296,7 +296,7 @@
   mkdir -p system/core
 
   run_soong
-  local mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$mtime1" != "$mtime2" ]]; then
     fail "Output Ninja file changed when top level directory changed"
   fi
@@ -306,7 +306,7 @@
   mkdir -p system/core/include
 
   run_soong
-  local mtime3=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime3=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$mtime2" = "$mtime3" ]]; then
     fail "Output Ninja file did not change when global include directory created"
   fi
@@ -317,7 +317,7 @@
 function test_add_file_to_soong_build() {
   setup
   run_soong
-  local mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   mkdir -p a
   cat > a/Android.bp <<'EOF'
@@ -379,7 +379,7 @@
 EOF
 
   run_soong
-  local mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$mtime1" == "$mtime2" ]]; then
     fail "Output Ninja file did not change"
   fi
@@ -457,7 +457,7 @@
 EOF
 
   run_soong
-  local mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   grep -q "Make it so" out/soong/build.ninja || fail "Original action not present"
 
@@ -489,7 +489,7 @@
 EOF
 
   run_soong
-  local mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$mtime1" == "$mtime2" ]]; then
     fail "Output Ninja file did not change"
   fi
@@ -514,20 +514,20 @@
   setup
 
   run_soong
-  local ninja_mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r ninja_mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   run_soong soong_docs
-  local docs_mtime1=$(stat -c "%y" out/soong/docs/soong_build.html)
+  local -r docs_mtime1=$(stat -c "%y" out/soong/docs/soong_build.html)
 
   run_soong soong_docs
-  local docs_mtime2=$(stat -c "%y" out/soong/docs/soong_build.html)
+  local -r docs_mtime2=$(stat -c "%y" out/soong/docs/soong_build.html)
 
   if [[ "$docs_mtime1" != "$docs_mtime2" ]]; then
     fail "Output Ninja file changed on null build"
   fi
 
   run_soong
-  local ninja_mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r ninja_mtime2=$(stat -c "%y" out/soong/build.ninja)
 
   if [[ "$ninja_mtime1" != "$ninja_mtime2" ]]; then
     fail "Output Ninja file changed on null build"
@@ -552,7 +552,7 @@
   run_ninja BUILD_BROKEN_SRC_DIR_IS_WRITABLE=false ${EXPECTED_OUT} &> /dev/null && \
     fail "Write to source tree should not work in a ReadOnly source tree"
 
-  if grep -q "${ERROR_MSG}" ${ERROR_LOG} && grep -q "${ERROR_HINT_PATTERN}" ${ERROR_LOG} ; then
+  if grep -q "${ERROR_MSG}" "${ERROR_LOG}" && grep -q "${ERROR_HINT_PATTERN}" "${ERROR_LOG}" ; then
     echo Error message and error hint found in logs >/dev/null
   else
     fail "Did not find Read-only error AND error hint in error.log"
@@ -562,7 +562,7 @@
   run_ninja BUILD_BROKEN_SRC_DIR_IS_WRITABLE=true ${EXPECTED_OUT} &> /dev/null || \
     fail "Write to source tree did not succeed in a ReadWrite source tree"
 
-  if  grep -q "${ERROR_MSG}\|${ERROR_HINT_PATTERN}" ${ERROR_LOG} ; then
+  if  grep -q "${ERROR_MSG}\|${ERROR_HINT_PATTERN}" "${ERROR_LOG}" ; then
     fail "Found read-only error OR error hint in error.log"
   fi
 }
@@ -606,11 +606,11 @@
     fail "BUILD file in symlink forest was not created";
   fi
 
-  local mtime1=$(stat -c "%y" out/soong/bp2build/a/b/BUILD.bazel)
+  local -r mtime1=$(stat -c "%y" out/soong/bp2build/a/b/BUILD.bazel)
 
   touch a/irrelevant.txt
   run_soong bp2build
-  local mtime2=$(stat -c "%y" out/soong/bp2build/a/b/BUILD.bazel)
+  local -r mtime2=$(stat -c "%y" out/soong/bp2build/a/b/BUILD.bazel)
 
   if [[ "$mtime1" != "$mtime2" ]]; then
     fail "BUILD.bazel file was regenerated"
@@ -657,10 +657,10 @@
   setup
 
   run_soong bp2build
-  local mtime1=$(stat -c "%y" out/soong/bp2build_workspace_marker)
+  local -r mtime1=$(stat -c "%y" out/soong/bp2build_workspace_marker)
 
   run_soong bp2build
-  local mtime2=$(stat -c "%y" out/soong/bp2build_workspace_marker)
+  local -r mtime2=$(stat -c "%y" out/soong/bp2build_workspace_marker)
 
   if [[ "$mtime1" != "$mtime2" ]]; then
     fail "Output Ninja file changed on null build"
@@ -717,19 +717,19 @@
   setup
 
   run_soong
-  local ninja_mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r ninja_mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   run_soong json-module-graph
-  local json_mtime1=$(stat -c "%y" out/soong/module-graph.json)
+  local -r json_mtime1=$(stat -c "%y" out/soong/module-graph.json)
 
   run_soong
-  local ninja_mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r ninja_mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$ninja_mtime1" != "$ninja_mtime2" ]]; then
     fail "Output Ninja file changed after writing JSON module graph"
   fi
 
   run_soong json-module-graph
-  local json_mtime2=$(stat -c "%y" out/soong/module-graph.json)
+  local -r json_mtime2=$(stat -c "%y" out/soong/module-graph.json)
   if [[ "$json_mtime1" != "$json_mtime2" ]]; then
     fail "JSON module graph file changed after writing Ninja file"
   fi
@@ -837,19 +837,19 @@
   setup
 
   run_soong
-  local output_mtime1=$(stat -c "%y" out/soong/build.ninja)
+  local -r output_mtime1=$(stat -c "%y" out/soong/build.ninja)
 
   run_soong bp2build
-  local output_mtime2=$(stat -c "%y" out/soong/build.ninja)
+  local -r output_mtime2=$(stat -c "%y" out/soong/build.ninja)
   if [[ "$output_mtime1" != "$output_mtime2" ]]; then
     fail "Output Ninja file changed when switching to bp2build"
   fi
 
-  local marker_mtime1=$(stat -c "%y" out/soong/bp2build_workspace_marker)
+  local -r marker_mtime1=$(stat -c "%y" out/soong/bp2build_workspace_marker)
 
   run_soong
-  local output_mtime3=$(stat -c "%y" out/soong/build.ninja)
-  local marker_mtime2=$(stat -c "%y" out/soong/bp2build_workspace_marker)
+  local -r output_mtime3=$(stat -c "%y" out/soong/build.ninja)
+  local -r marker_mtime2=$(stat -c "%y" out/soong/bp2build_workspace_marker)
   if [[ "$output_mtime1" != "$output_mtime3" ]]; then
     fail "Output Ninja file changed when switching to regular build from bp2build"
   fi
@@ -858,8 +858,8 @@
   fi
 
   run_soong bp2build
-  local output_mtime4=$(stat -c "%y" out/soong/build.ninja)
-  local marker_mtime3=$(stat -c "%y" out/soong/bp2build_workspace_marker)
+  local -r output_mtime4=$(stat -c "%y" out/soong/build.ninja)
+  local -r marker_mtime3=$(stat -c "%y" out/soong/bp2build_workspace_marker)
   if [[ "$output_mtime1" != "$output_mtime4" ]]; then
     fail "Output Ninja file changed when switching back to bp2build"
   fi
@@ -880,10 +880,10 @@
   setup
 
   run_soong queryview
-  local output_mtime1=$(stat -c "%y" out/soong/queryview.marker)
+  local -r output_mtime1=$(stat -c "%y" out/soong/queryview.marker)
 
   run_soong queryview
-  local output_mtime2=$(stat -c "%y" out/soong/queryview.marker)
+  local -r output_mtime2=$(stat -c "%y" out/soong/queryview.marker)
 
   if [[ "$output_mtime1" != "$output_mtime2" ]]; then
     fail "Queryview marker file changed on null build"