tests: Fix tools::is_hdd unit tests

Correct the unit tests for tools::is_hdd to avoid making assumptions
about the configuration of a particular device based solely on the
value of the __GLIBC__ preprocessor flag. Instead, rely on the
test invoker to provide paths for devices of specific types via
the process environment, thereby avoiding faulty assumptions and
improving the specificity of test assertions. To ensure appropriate
devices exist, add a script, tests/create_test_disks.sh, which
configures loopback devices mirroring relevant configurations.

.github/workflows/build.yml

@@ -192,6 +192,8 @@ jobs:
       run: sudo ${{env.APT_INSTALL_LINUX}}
     - name: install Python dependencies
       run: pip install requests psutil monotonic zmq deepdiff
+    - name: create dummy disk drives for testing
+      run: tests/create_test_disks.sh >> $GITHUB_ENV
     - name: tests
       env:
         CTEST_OUTPUT_ON_FAILURE: ON

tests/create_test_disks.sh

@@ -0,0 +1,90 @@
+#!/bin/bash
+
+set -e
+
+LOOP_DEVICE_MAJOR=7
+LOOP_DEVICE_MIN_ID=100
+
+echo_err() {
+    echo "$@" >&2
+}
+
+create_device_node() {
+    local -r last_id=$(find /dev/ -name 'loop[0-9]*' | sed 's/^.*loop//' | sort -r -n | head -1)
+    local id=$((last_id + 1))
+    if [[ "$id" -lt "$LOOP_DEVICE_MIN_ID" ]]; then
+        id="$LOOP_DEVICE_MIN_ID"
+    fi
+    local path
+    for (( i=0; i<10; i++ )); do
+        path="/dev/loop$id"
+        if [[ ! -e "$path" ]] && sudo mknod "$path" b "$LOOP_DEVICE_MAJOR" "$id"; then
+            echo "$path"
+            return 0
+        fi
+        $((id++))
+    done
+    return 1
+}
+
+device_mountpoint() {
+    local -r datadir="$1"
+    local -r dev="$2"
+    if [[ -z "$datadir" || -z "$dev" ]]; then
+        echo_err "Usage: device_mountpoint <data dir> <device>"
+        return 1
+    fi
+    echo "$datadir/mnt-$(basename "$dev")"
+}
+
+create_device() {
+    local -r datadir="$1"
+    if [[ -z "$datadir" ]]; then
+        echo_err "Usage: create_device <data dir>"
+        return 1
+    fi
+    local -r dev=$(create_device_node)
+    local -r fs="$datadir/$(basename "$dev").vhd"
+    local -r mountpoint=$(device_mountpoint "$datadir" "$dev")
+    echo_err
+    echo_err "# Device $dev"
+    dd if=/dev/zero of="$fs" bs=64K count=128 >/dev/null 2>&1
+    sudo losetup "$dev" "$fs"
+    sudo mkfs.ext4 "$dev" >/dev/null 2>&1
+    mkdir "$mountpoint"
+    sudo mount "$dev" "$mountpoint"
+    echo "$dev"
+}
+
+# Unused by default, but helpful for local development
+destroy_device() {
+    local -r datadir="$1"
+    local -r dev="$2"
+    if [[ -z "$datadir" || -z "$dev" ]]; then
+        echo_err "Usage: destroy_device <data dir> <device>"
+        return 1
+    fi
+    echo_err "Destroying device $dev"
+    sudo umount $(device_mountpoint "$datadir" "$dev")
+    sudo losetup -d "$dev"
+    sudo rm "$dev"
+}
+
+block_device_path() {
+    device_name=$(basename "$1")
+    device_minor=${device_name/#loop}
+    echo "/sys/dev/block/$LOOP_DEVICE_MAJOR:$device_minor"
+}
+
+tmpdir=$(mktemp --tmpdir -d monerotest.XXXXXXXX)
+echo_err "Creating devices using temporary directory: $tmpdir"
+
+dev_rot=$(create_device "$tmpdir")
+bdev_rot=$(block_device_path "$dev_rot")
+echo 1 | sudo tee "$bdev_rot/queue/rotational" >/dev/null
+echo MONERO_TEST_DEVICE_HDD=$(device_mountpoint "$tmpdir" "$dev_rot")
+
+dev_ssd=$(create_device "$tmpdir")
+bdev_ssd=$(block_device_path "$dev_ssd")
+echo 0 | sudo tee "$bdev_ssd/queue/rotational" >/dev/null
+echo MONERO_TEST_DEVICE_SSD=$(device_mountpoint "$tmpdir" "$dev_ssd")

tests/unit_tests/is_hdd.cpp

@@ -1,17 +1,36 @@
 #include "common/util.h"
+#include <cstdlib>
 #include <string>
 #include <gtest/gtest.h>
+#include <boost/optional/optional_io.hpp> /* required to output boost::optional in assertions */
+
+#ifndef GTEST_SKIP
+#include <iostream>
+#define SKIP_TEST(reason) do {std::cerr << "Skipping test: " << reason << std::endl; return;} while(0)
+#else
+#define SKIP_TEST(reason) GTEST_SKIP() << reason
+#endif
 
 #if defined(__GLIBC__)
-TEST(is_hdd, linux_os_root)
-{
-  std::string path = "/";
-  EXPECT_TRUE(tools::is_hdd(path.c_str()) != boost::none);
+TEST(is_hdd, rotational_drive) {
+  const char *hdd = std::getenv("MONERO_TEST_DEVICE_HDD");
+  if (hdd == nullptr)
+    SKIP_TEST("No rotational disk device configured");
+  EXPECT_EQ(tools::is_hdd(hdd), boost::optional<bool>(true));
 }
-#else
-TEST(is_hdd, unknown_os)
-{
-  std::string path = "";
-  EXPECT_FALSE(tools::is_hdd(path.c_str()) != boost::none);
+
+TEST(is_hdd, ssd) {
+  const char *ssd = std::getenv("MONERO_TEST_DEVICE_SSD");
+  if (ssd == nullptr)
+    SKIP_TEST("No SSD device configured");
+  EXPECT_EQ(tools::is_hdd(ssd), boost::optional<bool>(false));
+}
+
+TEST(is_hdd, unknown_attrs) {
+  EXPECT_EQ(tools::is_hdd("/dev/null"), boost::none);
 }
 #endif
+TEST(is_hdd, stability)
+{
+  EXPECT_NO_THROW(tools::is_hdd(""));
+}