fastboot: Add a test for super_flash_helper.

This test checks that the sparsing logic matches a canonical sample
output.

Bug: N/A
Test: fastboot_test
Change-Id: Ic7bad08a79e4223f8352db2397b741c2179e76bb

fastboot/Android.bp

@@ -378,6 +378,7 @@ cc_test_host {
         "fastboot_test.cpp",
         "socket_mock.cpp",
         "socket_test.cpp",
+        "super_flash_helper_test.cpp",
         "tcp_test.cpp",
         "udp_test.cpp",
     ],
@@ -395,6 +396,12 @@ cc_test_host {
     },
 
     test_suites: ["general-tests"],
+
+    data: [
+        "testdata/super.img",
+        "testdata/super_empty.img",
+        "testdata/system.img",
+    ],
 }
 
 cc_test_host {

fastboot/fastboot_test.cpp

@@ -16,6 +16,7 @@
 
 #include "fastboot.h"
 
+#include <android-base/logging.h>
 #include <gtest/gtest.h>
 
 TEST(FastBoot, ParseOsPatchLevel) {
@@ -201,3 +202,11 @@ TEST(FastBoot, ParseRequirementLineMalformed) {
     // No spaces allowed before between require-for-product and :.
     ParseRequirementLineTestMalformed("require-for-product :");
 }
+
+int main(int argc, char* argv[]) {
+    ::testing::InitGoogleTest(&argc, argv);
+    android::base::InitLogging(argv);
+    android::base::SetMinimumLogSeverity(android::base::VERBOSE);
+
+    return RUN_ALL_TESTS();
+}

fastboot/super_flash_helper_test.cpp

@@ -0,0 +1,88 @@
+//
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include "super_flash_helper.h"
+
+#include <unistd.h>
+
+#include <android-base/file.h>
+#include <android-base/unique_fd.h>
+#include <gtest/gtest.h>
+#include <sparse/sparse.h>
+
+using android::base::unique_fd;
+
+unique_fd OpenTestFile(const std::string& file, int flags) {
+    std::string path = "testdata/" + file;
+
+    unique_fd fd(open(path.c_str(), flags));
+    if (fd >= 0) {
+        return fd;
+    }
+
+    path = android::base::GetExecutableDirectory() + "/" + path;
+    return unique_fd{open(path.c_str(), flags)};
+}
+
+class TestImageSource final : public ImageSource {
+  public:
+    bool ReadFile(const std::string&, std::vector<char>*) const override {
+        // Not used here.
+        return false;
+    }
+    unique_fd OpenFile(const std::string& name) const override {
+        return OpenTestFile(name, O_RDONLY | O_CLOEXEC);
+    }
+};
+
+TEST(SuperFlashHelper, ImageEquality) {
+    auto super_empty_fd = OpenTestFile("super_empty.img", O_RDONLY);
+    ASSERT_GE(super_empty_fd, 0);
+
+    TestImageSource source;
+    SuperFlashHelper helper(source);
+    ASSERT_TRUE(helper.Open(super_empty_fd));
+    ASSERT_TRUE(helper.AddPartition("system_a", "system.img", false));
+
+    auto sparse_file = helper.GetSparseLayout();
+    ASSERT_NE(sparse_file, nullptr);
+
+    TemporaryFile fb_super;
+    ASSERT_GE(fb_super.fd, 0);
+    ASSERT_EQ(sparse_file_write(sparse_file.get(), fb_super.fd, false, false, false), 0);
+
+    auto real_super_fd = OpenTestFile("super.img", O_RDONLY);
+    ASSERT_GE(real_super_fd, 0);
+
+    std::string expected(get_file_size(real_super_fd), '\0');
+    ASSERT_FALSE(expected.empty());
+    ASSERT_TRUE(android::base::ReadFully(real_super_fd, expected.data(), expected.size()));
+
+    std::string actual(get_file_size(fb_super.fd), '\0');
+    ASSERT_FALSE(actual.empty());
+    ASSERT_EQ(lseek(fb_super.fd, 0, SEEK_SET), 0);
+    ASSERT_TRUE(android::base::ReadFully(fb_super.fd, actual.data(), actual.size()));
+
+    // The helper doesn't add any extra zeroes to the image, whereas lpmake does, to
+    // pad to the entire super size.
+    ASSERT_LE(actual.size(), expected.size());
+    for (size_t i = 0; i < actual.size(); i++) {
+        ASSERT_EQ(actual[i], expected[i]) << "byte mismatch at position " << i;
+    }
+    for (size_t i = actual.size(); i < expected.size(); i++) {
+        ASSERT_EQ(expected[i], 0) << "byte mismatch at position " << i;
+    }
+}

fastboot/testdata/make_super_images.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+set -e
+set -x
+
+lpmake \
+    --device-size=auto \
+    --metadata-size=4096 \
+    --metadata-slots=3 \
+    --partition=system_a:readonly:0 \
+    --alignment=16384 \
+    --output=super_empty.img
+
+lpmake \
+    --device-size=auto \
+    --metadata-size=4096 \
+    --metadata-slots=3 \
+    --partition=system_a:readonly:0 \
+    --alignment=16384 \
+    --output=super.img \
+    --image=system_a=system.img