Add a test for CombinedAndroidBuild

Bug: b/485364059

Author: Databean

base/cvd/cuttlefish/host/commands/assemble_cvd/android_build/BUILD.bazel

@@ -84,6 +84,20 @@ cf_cc_library(
     ],
 )
 
+cf_cc_test(
+    name = "combined_android_build_test",
+    srcs = ["combined_android_build_test.cc"],
+    deps = [
+        "//cuttlefish/host/commands/assemble_cvd/android_build",
+        "//cuttlefish/host/commands/assemble_cvd/android_build:combined_android_build",
+        "//cuttlefish/host/commands/assemble_cvd/android_build:fake_android_build",
+        "//cuttlefish/result",
+        "//cuttlefish/result:result_matchers",
+        "@googletest//:gtest",
+        "@googletest//:gtest_main",
+    ],
+)
+
 cf_cc_library(
     name = "fake_android_build",
     testonly = True,

base/cvd/cuttlefish/host/commands/assemble_cvd/android_build/combined_android_build_test.cc

@@ -0,0 +1,109 @@
+//
+// Copyright (C) 2026 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 "cuttlefish/host/commands/assemble_cvd/android_build/combined_android_build.h"
+
+#include <functional>
+#include <memory>
+#include <set>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "gmock/gmock-matchers.h"
+#include "gtest/gtest.h"
+
+#include "cuttlefish/host/commands/assemble_cvd/android_build/android_build.h"
+#include "cuttlefish/host/commands/assemble_cvd/android_build/fake_android_build.h"
+#include "cuttlefish/result/result.h"
+#include "cuttlefish/result/result_matchers.h"
+
+namespace cuttlefish {
+namespace {
+
+Result<std::unique_ptr<AndroidBuild>> CombineFakeBuilds(
+    std::vector<FakeAndroidBuild> fakes) {
+  std::vector<std::unique_ptr<AndroidBuild>> build_ptrs;
+  for (FakeAndroidBuild fake : fakes) {
+    build_ptrs.emplace_back(
+        std::make_unique<FakeAndroidBuild>(std::move(fake)));
+  }
+  return CF_EXPECT(CombinedAndroidBuild("Fakes", std::move(build_ptrs)));
+}
+
+TEST(CombinedAndroidBuild, Construct) {
+  EXPECT_THAT(CombineFakeBuilds({FakeAndroidBuild(), FakeAndroidBuild()}),
+              IsOk());
+}
+
+TEST(CombinedAndroidBuild, MergesImages) {
+  FakeAndroidBuild with_a;
+  with_a.AddExtractedImage("a", "a_file");
+
+  FakeAndroidBuild with_b;
+  with_b.AddExtractedImage("b", "b_file");
+
+  std::unique_ptr<AndroidBuild> combined = *CombineFakeBuilds({with_a, with_b});
+
+  std::set<std::string, std::less<void>> expected = {"a", "b"};
+  EXPECT_THAT(combined->Images(), IsOkAndValue(expected));
+  EXPECT_THAT(combined->ImageFile("a"), IsOkAndValue("a_file"));
+  EXPECT_THAT(combined->ImageFile("b"), IsOkAndValue("b_file"));
+}
+
+TEST(CombinedAndroidBuild, PrefersExtractedImage) {
+  FakeAndroidBuild unextracted;
+  unextracted.AddUnextractedImage("img");
+
+  FakeAndroidBuild extracted;
+  extracted.AddExtractedImage("img", "extracted");
+
+  std::unique_ptr<AndroidBuild> combined =
+      *CombineFakeBuilds({extracted, unextracted});
+
+  EXPECT_THAT(combined->ImageFile("img", false), IsOkAndValue("extracted"));
+  EXPECT_THAT(combined->ImageFile("img", true), IsOkAndValue("extracted"));
+}
+
+TEST(CombinedAndroidBuild, IgnoresMissingImage) {
+  FakeAndroidBuild unextracted;
+  unextracted.AddUnextractedImage("img");
+  EXPECT_THAT(unextracted.SetExtractDir("extract"), IsOk());
+
+  FakeAndroidBuild missing;
+  missing.AddMissingImage("img");
+
+  std::unique_ptr<AndroidBuild> combined =
+      *CombineFakeBuilds({missing, unextracted});
+
+  EXPECT_THAT(combined->ImageFile("img", false), IsError());
+  EXPECT_THAT(combined->ImageFile("img", true), IsOkAndValue("extract/img"));
+}
+
+TEST(CombinedAndroidBuild, MergesLogicalPartitions) {
+  FakeAndroidBuild with_a;
+  with_a.SetLogicalPartitions({"a"});
+
+  FakeAndroidBuild with_b;
+  with_b.SetLogicalPartitions({"b"});
+
+  std::unique_ptr<AndroidBuild> combined = *CombineFakeBuilds({with_a, with_b});
+
+  std::set<std::string, std::less<void>> expected = {"a", "b"};
+  EXPECT_THAT(combined->LogicalPartitions(), IsOkAndValue(expected));
+}
+
+}  // namespace
+}  // namespace cuttlefish