From c43cf67b40a2646ff7c5443ef7d4e3562e06ac08 Mon Sep 17 00:00:00 2001
From: Googler <tjgq@google.com>
Date: Fri, 27 Sep 2024 05:28:18 -0700
Subject: [PATCH] Add an end-to-end test for disk cache garbage collection.

PiperOrigin-RevId: 679550494
Change-Id: Ie397d3e498423ce1dd121e786c8e8e129bcb87f2
---
 src/test/shell/bazel/disk_cache_test.sh       | 39 +++++++++++++++++++
 .../integration/validation_actions_test.sh    | 16 --------
 src/test/shell/unittest.bash                  | 26 +++++++++++++
 3 files changed, 65 insertions(+), 16 deletions(-)

diff --git a/src/test/shell/bazel/disk_cache_test.sh b/src/test/shell/bazel/disk_cache_test.sh
index cb709e8db36509..5433f042ac943a 100755
--- a/src/test/shell/bazel/disk_cache_test.sh
+++ b/src/test/shell/bazel/disk_cache_test.sh
@@ -127,4 +127,43 @@ EOF
   expect_log "(cached) PASSED"
 }
 
+function test_garbage_collection() {
+  local -r CACHE_DIR="${TEST_TMPDIR}/cache"
+  rm -rf "$CACHE_DIR"
+
+  mkdir -p a
+  touch a/BUILD
+
+  # Populate the disk cache with some fake entries totalling 4 MB in size.
+  create_file_with_size_and_mtime "${CACHE_DIR}/cas/123" 1M "202401010100"
+  create_file_with_size_and_mtime "${CACHE_DIR}/ac/456"  1M "202401010200"
+  create_file_with_size_and_mtime "${CACHE_DIR}/cas/abc" 1M "202401010300"
+  create_file_with_size_and_mtime "${CACHE_DIR}/ac/def"  1M "202401010400"
+
+  # Run a build and request an immediate garbage collection.
+  # Note that this build doesn't write anything to the disk cache.
+  bazel build --disk_cache="$CACHE_DIR" \
+    --experimental_disk_cache_gc_max_size=2M \
+    --experimental_disk_cache_gc_idle_delay=0 \
+    //a:BUILD >& $TEST_log || fail "Expected build to succeed"
+
+  # Give the idle task a bit of time to run.
+  sleep 1
+
+  # Expect the two oldest entries to have been deleted to reduce size to 2 MB.
+  assert_not_exists "${CACHE_DIR}/cas/123"
+  assert_not_exists "${CACHE_DIR}/ac/456"
+  assert_exists "${CACHE_DIR}/cas/abc"
+  assert_exists "${CACHE_DIR}/ac/def"
+}
+
+function create_file_with_size_and_mtime() {
+  local -r path=$1
+  local -r size=$2
+  local -r mtime=$3
+  mkdir -p "$(dirname "$path")"
+  dd if=/dev/zero of="$path" bs="$size" count=1
+  touch -t "$mtime" "$path"
+}
+
 run_suite "disk cache test"
diff --git a/src/test/shell/integration/validation_actions_test.sh b/src/test/shell/integration/validation_actions_test.sh
index 1f68bbabfaf246..77f788e23a0107 100755
--- a/src/test/shell/integration/validation_actions_test.sh
+++ b/src/test/shell/integration/validation_actions_test.sh
@@ -216,22 +216,6 @@ EOF
   chmod +x validation_actions/validation_tool
 }
 
-function assert_exists() {
-  path="$1"
-  [ -f "$path" ] && return 0
-
-  fail "Expected file '$path' to exist, but it did not"
-  return 1
-}
-
-function assert_not_exists() {
-  path="$1"
-  [ ! -f "$path" ] && return 0
-
-  fail "Expected file '$path' to not exist, but it did"
-  return 1
-}
-
 #### Tests #####################################################################
 
 function test_validation_actions() {
diff --git a/src/test/shell/unittest.bash b/src/test/shell/unittest.bash
index 46743cdfce70f9..41192a71d2b9d7 100644
--- a/src/test/shell/unittest.bash
+++ b/src/test/shell/unittest.bash
@@ -519,6 +519,32 @@ function assert_contains_n() {
     return 1
 }
 
+# Usage: assert_exists <file> [error-message]
+# Asserts that the file exists.
+function assert_exists() {
+    local file=$1
+    local message=${2:-"Expected '$file' to exist"}
+    if [[ -f "$file" ]]; then
+        return 0
+    fi
+
+    fail "$message"
+    return 1
+}
+
+# Usage: assert_not_exists <file> [error-message]
+# Asserts that the file does not exist.
+function assert_not_exists() {
+    local file=$1
+    local message=${2:-"Expected '$file' to not exist"}
+    if ! [[ -f "$file" ]]; then
+        return 0
+    fi
+
+    fail "$message"
+    return 1
+}
+
 # Usage: assert_empty_file <file> [error-message]
 # Asserts that the file exists and is empty. On failure copies the file to
 # undeclared outputs, prints the specified (optional) error message, and returns