test: test command line tool usage / help

src/dwarfs_main.cpp

@@ -132,6 +132,7 @@ struct dwarfs_userdata {
   dwarfs_userdata(dwarfs_userdata const&) = delete;
   dwarfs_userdata& operator=(dwarfs_userdata const&) = delete;
 
+  bool is_help{false};
   options opts;
   stream_logger lgr;
   filesystem_v2 fs;
@@ -962,7 +963,7 @@ void usage(std::ostream& os, std::filesystem::path const& progname) {
 #if !DWARFS_FUSE_LOWLEVEL
      << "USING HIGH-LEVEL FUSE API\n\n"
 #endif
-     << "usage: " << progname.filename().string()
+     << "Usage: " << progname.filename().string()
      << " <image> <mountpoint> [options]\n\n"
      << "DWARFS options:\n"
      << "    -o cachesize=SIZE      set size of block cache (512M)\n"
@@ -995,8 +996,6 @@ void usage(std::ostream& os, std::filesystem::path const& progname) {
   fuse_main(args.argc, args.argv, &fsops, nullptr);
   fuse_opt_free_args(&args);
 #endif
-
-  ::exit(1);
 }
 
 int option_hdl(void* data, char const* arg, int key,
@@ -1022,7 +1021,8 @@ int option_hdl(void* data, char const* arg, int key,
 
   case FUSE_OPT_KEY_OPT:
     if (::strncmp(arg, "-h", 2) == 0 || ::strncmp(arg, "--help", 6) == 0) {
-      usage(userdata.iol.err, opts.progname);
+      userdata.is_help = true;
+      return -1;
     }
     break;
 
@@ -1265,7 +1265,8 @@ int dwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
   struct fuse_cmdline_opts fuse_opts;
 
   if (fuse_parse_cmdline(&args, &fuse_opts) == -1 || !fuse_opts.mountpoint) {
-    usage(iol.err, opts.progname);
+    usage(iol.out, opts.progname);
+    return userdata.is_help ? 0 : 1;
   }
 
   if (fuse_opts.foreground) {
@@ -1278,7 +1279,8 @@ int dwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
   int mt, fg;
 
   if (fuse_parse_cmdline(&args, &mountpoint, &mt, &fg) == -1 || !mountpoint) {
-    usage(iol.err, opts.progname);
+    usage(iol.out, opts.progname);
+    return userdata.is_help ? 0 : 1;
   }
 
   if (fg) {
@@ -1349,7 +1351,8 @@ int dwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
   }
 
   if (!opts.seen_mountpoint) {
-    usage(iol.err, opts.progname);
+    usage(iol.out, opts.progname);
+    return 1;
   }
 
   LOG_PROXY(debug_logger_policy, userdata.lgr);

src/dwarfsck_main.cpp

@@ -113,8 +113,10 @@ int dwarfsck_main(int argc, sys_char** argv, iolayer const& iol) {
     return 1;
   }
 
+  auto constexpr usage = "Usage: dwarfsck [OPTIONS...]\n";
+
   if (vm.count("help") or !vm.count("input")) {
-    iol.out << tool_header("dwarfsck") << opts << "\n";
+    iol.out << tool_header("dwarfsck") << usage << "\n" << opts << "\n";
     return 0;
   }
 

src/dwarfsextract_main.cpp

@@ -103,9 +103,12 @@ int dwarfsextract_main(int argc, sys_char** argv, iolayer const& iol) {
     return 1;
   }
 
+  auto constexpr usage = "Usage: dwarfsextract [OPTIONS...]\n";
+
   if (vm.count("help") or !vm.count("input")) {
-    iol.err << tool_header("dwarfsextract") << "using "
+    iol.out << tool_header("dwarfsextract") << "using "
             << ::archive_version_string() << "\n\n"
+            << usage << "\n"
             << opts << "\n";
     return 0;
   }

src/mkdwarfs_main.cpp

@@ -621,7 +621,7 @@ int mkdwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
     return 1;
   }
 
-  auto const usage = "Usage: mkdwarfs [OPTIONS...]\n";
+  auto constexpr usage = "Usage: mkdwarfs [OPTIONS...]\n";
 
   if (vm.count("long-help")) {
     std::string_view constexpr block_data_hdr{"Block Data"};

test/test_helpers.h

@@ -174,6 +174,7 @@ class test_file_access : public file_access {
 
 class test_iolayer {
  public:
+  test_iolayer();
   test_iolayer(std::shared_ptr<os_access_mock> os);
   test_iolayer(std::shared_ptr<os_access_mock> os,
                std::shared_ptr<file_access const> fa);

test/test_iolayer.cpp

@@ -170,6 +170,9 @@ std::string test_terminal::colored(std::string text, termcolor color,
   return result;
 }
 
+test_iolayer::test_iolayer()
+    : test_iolayer{os_access_mock::create_test_instance()} {}
+
 test_iolayer::test_iolayer(std::shared_ptr<os_access_mock> os)
     : test_iolayer{std::move(os), create_file_access_generic()} {}
 

test/tool_main_test.cpp

@@ -21,6 +21,7 @@
 
 #include <filesystem>
 
+#include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
 #include <fmt/format.h>
@@ -42,8 +43,140 @@ namespace {
 auto test_dir = fs::path(TEST_DATA_DIR).make_preferred();
 auto audio_data_dir = test_dir / "pcmaudio";
 
+class tool_main_test : public testing::Test {
+ public:
+  void SetUp() override { iol = std::make_unique<test::test_iolayer>(); }
+
+  void TearDown() override { iol.reset(); }
+
+  std::string out() const { return iol->out(); }
+  std::string err() const { return iol->err(); }
+
+  std::unique_ptr<test::test_iolayer> iol;
+};
+
 } // namespace
 
+class mkdwarfs_main_test : public tool_main_test {
+ public:
+  int run(std::vector<std::string> args) {
+    args.insert(args.begin(), "mkdwarfs");
+    return mkdwarfs_main(args, iol->get());
+  }
+};
+
+class dwarfsck_main_test : public tool_main_test {
+ public:
+  int run(std::vector<std::string> args) {
+    args.insert(args.begin(), "dwarfsck");
+    return dwarfsck_main(args, iol->get());
+  }
+};
+
+class dwarfsextract_main_test : public tool_main_test {
+ public:
+  int run(std::vector<std::string> args) {
+    args.insert(args.begin(), "dwarfsextract");
+    return dwarfsextract_main(args, iol->get());
+  }
+};
+
+TEST_F(mkdwarfs_main_test, no_cmdline_args) {
+  auto exit_code = run({});
+  EXPECT_EQ(exit_code, 0);
+  EXPECT_TRUE(err().empty());
+  EXPECT_FALSE(out().empty());
+  EXPECT_THAT(out(), ::testing::HasSubstr("Usage: mkdwarfs"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("--help"));
+}
+
+TEST_F(dwarfsck_main_test, no_cmdline_args) {
+  auto exit_code = run({});
+  EXPECT_EQ(exit_code, 0);
+  EXPECT_TRUE(err().empty());
+  EXPECT_FALSE(out().empty());
+  EXPECT_THAT(out(), ::testing::HasSubstr("Usage: dwarfsck"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("--help"));
+}
+
+TEST_F(dwarfsextract_main_test, no_cmdline_args) {
+  auto exit_code = run({});
+  EXPECT_EQ(exit_code, 0);
+  EXPECT_TRUE(err().empty());
+  EXPECT_FALSE(out().empty());
+  EXPECT_THAT(out(), ::testing::HasSubstr("Usage: dwarfsextract"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("--help"));
+}
+
+TEST_F(mkdwarfs_main_test, invalid_cmdline_args) {
+  auto exit_code = run({"--some-invalid-option"});
+  EXPECT_EQ(exit_code, 1);
+  EXPECT_FALSE(err().empty());
+  EXPECT_TRUE(out().empty());
+  EXPECT_THAT(err(), ::testing::HasSubstr(
+                         "unrecognised option '--some-invalid-option'"));
+}
+
+TEST_F(dwarfsck_main_test, invalid_cmdline_args) {
+  auto exit_code = run({"--some-invalid-option"});
+  EXPECT_EQ(exit_code, 1);
+  EXPECT_FALSE(err().empty());
+  EXPECT_TRUE(out().empty());
+  EXPECT_THAT(err(), ::testing::HasSubstr(
+                         "unrecognised option '--some-invalid-option'"));
+}
+
+TEST_F(dwarfsextract_main_test, invalid_cmdline_args) {
+  auto exit_code = run({"--some-invalid-option"});
+  EXPECT_EQ(exit_code, 1);
+  EXPECT_FALSE(err().empty());
+  EXPECT_TRUE(out().empty());
+  EXPECT_THAT(err(), ::testing::HasSubstr(
+                         "unrecognised option '--some-invalid-option'"));
+}
+
+TEST_F(mkdwarfs_main_test, cmdline_help_arg) {
+  auto exit_code = run({"--help"});
+  EXPECT_EQ(exit_code, 0);
+  EXPECT_TRUE(err().empty());
+  EXPECT_FALSE(out().empty());
+  EXPECT_THAT(out(), ::testing::HasSubstr("Usage: mkdwarfs"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("--help"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("--long-help"));
+  // check that the detailed help is not shown
+  EXPECT_THAT(out(), ::testing::Not(::testing::HasSubstr("Advanced options:")));
+  EXPECT_THAT(out(),
+              ::testing::Not(::testing::HasSubstr("Compression algorithms:")));
+}
+
+TEST_F(mkdwarfs_main_test, cmdline_long_help_arg) {
+  auto exit_code = run({"--long-help"});
+  EXPECT_EQ(exit_code, 0);
+  EXPECT_TRUE(err().empty());
+  EXPECT_FALSE(out().empty());
+  EXPECT_THAT(out(), ::testing::HasSubstr("Usage: mkdwarfs"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("Advanced options:"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("Compression level defaults:"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("Compression algorithms:"));
+  EXPECT_THAT(out(), ::testing::HasSubstr("Categories:"));
+}
+
+TEST_F(dwarfsck_main_test, cmdline_help_arg) {
+  auto exit_code = run({"--help"});
+  EXPECT_EQ(exit_code, 0);
+  EXPECT_TRUE(err().empty());
+  EXPECT_FALSE(out().empty());
+  EXPECT_THAT(out(), ::testing::HasSubstr("Usage: dwarfsck"));
+}
+
+TEST_F(dwarfsextract_main_test, cmdline_help_arg) {
+  auto exit_code = run({"--help"});
+  EXPECT_EQ(exit_code, 0);
+  EXPECT_TRUE(err().empty());
+  EXPECT_FALSE(out().empty());
+  EXPECT_THAT(out(), ::testing::HasSubstr("Usage: dwarfsextract"));
+}
+
 class categorizer_test : public testing::TestWithParam<std::string> {};
 
 TEST_P(categorizer_test, end_to_end) {