Allow using a shared repository cache and install base for our integr…

…ation tests.

This change doesn't do anything (besides printing a message) unless you run Bazel's tests with the new environment variables.

The environment variables will be set to appropriate platform-specific values by the CI scripts.

PiperOrigin-RevId: 231389821

src/test/shell/testenv.sh

@@ -286,6 +286,21 @@ common --color=no --curses=no
 
 ${EXTRA_BAZELRC:-}
 EOF
+
+  if [[ -d ${REPOSITORY_CACHE:-} ]]; then
+    echo "testenv.sh: Using repository cache at $REPOSITORY_CACHE."
+    cat >>$TEST_TMPDIR <<EOF
+sync --repository_cache=$REPOSITORY_CACHE --experimental_repository_cache_hardlinks
+fetch --repository_cache=$REPOSITORY_CACHE --experimental_repository_cache_hardlinks
+build --repository_cache=$REPOSITORY_CACHE --experimental_repository_cache_hardlinks
+query --repository_cache=$REPOSITORY_CACHE --experimental_repository_cache_hardlinks
+EOF
+  fi
+
+  if [[ -d ${INSTALL_BASE:-} ]]; then
+    echo "testenv.sh: Using shared install base at $INSTALL_BASE."
+    echo "startup --install_base=$INSTALL_BASE" >> $TEST_TMPDIR/bazelrc
+  fi
 }
 
 function setup_android_sdk_support() {