src/process_tree_test.cc

// Copyright 2026 Google Inc. All Rights Reserved.
//
// 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 "process_tree.h"

#include "test.h"

TEST(ProcessTreeTest, ConstructionAndPrinting) {
  std::vector<ProcessTree::ProcessInfo> processes = {
    { 100, 1, "init", {} },
    { 200, 100, "ninja", {} },
    { 201, 200, "python", { { "python", "script.py" }, true } },
    { 202, 201, "gcc", { { "gcc", "-c", "foo.c" }, true } },
    { 203, 200, "bash", {} },
    { 204, 203, "ls", { { "ls", "-l" }, true } },
  };

  ProcessTree::SystemSnapshot snapshot;
  snapshot.processes = processes;
  for (const auto& proc : snapshot.processes) {
    snapshot.ppid_to_children[proc.ppid].push_back(proc.pid);
    snapshot.pid_to_info[proc.pid] = &proc;
  }

  ProcessTree tree(200, snapshot);

  std::unordered_map<ProcessTree::Pid, std::string> known;
  known[200] = "ninja build";

  std::string output;
  tree.Print(1, known, &output);

  EXPECT_NE(std::string::npos, output.find("- [PID    201]: python script.py"));
  EXPECT_NE(std::string::npos, output.find("  - [PID    202]: gcc -c foo.c"));
  EXPECT_NE(std::string::npos, output.find("- [PID    203]: [bash]"));
  EXPECT_NE(std::string::npos, output.find("  - [PID    204]: ls -l"));
}

TEST(ProcessTreeTest, DisconnectedTree) {
  std::vector<ProcessTree::ProcessInfo> processes = {
    { 100, 1, "init", {} },
    { 300, 400, "orphan", {} },
  };

  ProcessTree::SystemSnapshot snapshot;
  snapshot.processes = processes;
  for (const auto& proc : snapshot.processes) {
    snapshot.ppid_to_children[proc.ppid].push_back(proc.pid);
    snapshot.pid_to_info[proc.pid] = &proc;
  }

  // Root PID 200 is not in the list.
  ProcessTree tree(200, snapshot);

  std::string output;
  tree.Print(1, {}, &output);

  EXPECT_EQ("", output);
}