Add test for ArgsManager::GetChainName

There was some test coverage previously, but it was limited and didn't test
conflicting and negated arguments.

src/test/util_tests.cpp

@@ -601,7 +601,7 @@ BOOST_AUTO_TEST_CASE(util_GetChainName)
 //   outside a network section, and non-network specific settings like "-server"
 //   that aren't sensitive to the network.
 //
-struct SettingsMergeTestingSetup : public BasicTestingSetup {
+struct ArgsMergeTestingSetup : public BasicTestingSetup {
     //! Max number of actions to sequence together. Can decrease this when
     //! debugging to make test results easier to understand.
     static constexpr int MAX_ACTIONS = 3;
@@ -661,11 +661,11 @@ struct SettingsMergeTestingSetup : public BasicTestingSetup {
 // test parses and merges settings, representing the results as strings that get
 // compared against an expected hash. To debug, the result strings can be dumped
 // to a file (see comments below).
-BOOST_FIXTURE_TEST_CASE(util_SettingsMerge, SettingsMergeTestingSetup)
+BOOST_FIXTURE_TEST_CASE(util_ArgsMerge, ArgsMergeTestingSetup)
 {
     CHash256 out_sha;
     FILE* out_file = nullptr;
-    if (const char* out_path = getenv("SETTINGS_MERGE_TEST_OUT")) {
+    if (const char* out_path = getenv("ARGS_MERGE_TEST_OUT")) {
         out_file = fsbridge::fopen(out_path, "w");
         if (!out_file) throw std::system_error(errno, std::generic_category(), "fopen failed");
     }
@@ -767,7 +767,7 @@ BOOST_FIXTURE_TEST_CASE(util_SettingsMerge, SettingsMergeTestingSetup)
 
     // If check below fails, should manually dump the results with:
     //
-    //   SETTINGS_MERGE_TEST_OUT=results.txt ./test_bitcoin --run_test=util_tests/util_SettingsMerge
+    //   ARGS_MERGE_TEST_OUT=results.txt ./test_bitcoin --run_test=util_tests/util_ArgsMerge
     //
     // And verify diff against previous results to make sure the changes are expected.
     //
@@ -777,6 +777,108 @@ BOOST_FIXTURE_TEST_CASE(util_SettingsMerge, SettingsMergeTestingSetup)
     BOOST_CHECK_EQUAL(out_sha_hex, "b835eef5977d69114eb039a976201f8c7121f34fe2b7ea2b73cafb516e5c9dc8");
 }
 
+// Similar test as above, but for ArgsManager::GetChainName function.
+struct ChainMergeTestingSetup : public BasicTestingSetup {
+    static constexpr int MAX_ACTIONS = 2;
+
+    enum Action { NONE, ENABLE_TEST, DISABLE_TEST, NEGATE_TEST, ENABLE_REG, DISABLE_REG, NEGATE_REG };
+    using ActionList = Action[MAX_ACTIONS];
+
+    //! Enumerate all possible test configurations.
+    template <typename Fn>
+    void ForEachMergeSetup(Fn&& fn)
+    {
+        ActionList arg_actions = {};
+        ForEachNoDup(arg_actions, ENABLE_TEST, NEGATE_REG, [&] {
+            ActionList conf_actions = {};
+            ForEachNoDup(conf_actions, ENABLE_TEST, NEGATE_REG, [&] { fn(arg_actions, conf_actions); });
+        });
+    }
+};
+
+BOOST_FIXTURE_TEST_CASE(util_ChainMerge, ChainMergeTestingSetup)
+{
+    CHash256 out_sha;
+    FILE* out_file = nullptr;
+    if (const char* out_path = getenv("CHAIN_MERGE_TEST_OUT")) {
+        out_file = fsbridge::fopen(out_path, "w");
+        if (!out_file) throw std::system_error(errno, std::generic_category(), "fopen failed");
+    }
+
+    ForEachMergeSetup([&](const ActionList& arg_actions, const ActionList& conf_actions) {
+        TestArgsManager parser;
+        LOCK(parser.cs_args);
+        parser.AddArg("-regtest", "regtest", false, OptionsCategory::OPTIONS);
+        parser.AddArg("-testnet", "testnet", false, OptionsCategory::OPTIONS);
+
+        auto arg = [](Action action) { return action == ENABLE_TEST  ? "-testnet=1"   :
+                                              action == DISABLE_TEST ? "-testnet=0"   :
+                                              action == NEGATE_TEST  ? "-notestnet=1" :
+                                              action == ENABLE_REG   ? "-regtest=1"   :
+                                              action == DISABLE_REG  ? "-regtest=0"   :
+                                              action == NEGATE_REG   ? "-noregtest=1" : nullptr; };
+
+        std::string desc;
+        std::vector<const char*> argv = {"ignored"};
+        for (Action action : arg_actions) {
+            const char* argstr = arg(action);
+            if (!argstr) break;
+            argv.push_back(argstr);
+            desc += " ";
+            desc += argv.back();
+        }
+        std::string error;
+        BOOST_CHECK(parser.ParseParameters(argv.size(), argv.data(), error));
+        BOOST_CHECK_EQUAL(error, "");
+
+        std::string conf;
+        for (Action action : conf_actions) {
+            const char* argstr = arg(action);
+            if (!argstr) break;
+            desc += " ";
+            desc += argstr + 1;
+            conf += argstr + 1;
+        }
+        std::istringstream conf_stream(conf);
+        BOOST_CHECK(parser.ReadConfigStream(conf_stream, "filepath", error));
+        BOOST_CHECK_EQUAL(error, "");
+
+        desc += " || ";
+        try {
+            desc += parser.GetChainName();
+        } catch (const std::runtime_error& e) {
+            desc += "error: ";
+            desc += e.what();
+        }
+        desc += "\n";
+
+        out_sha.Write((const unsigned char*)desc.data(), desc.size());
+        if (out_file) {
+            BOOST_REQUIRE(fwrite(desc.data(), 1, desc.size(), out_file) == desc.size());
+        }
+    });
+
+    if (out_file) {
+        if (fclose(out_file)) throw std::system_error(errno, std::generic_category(), "fclose failed");
+        out_file = nullptr;
+    }
+
+    unsigned char out_sha_bytes[CSHA256::OUTPUT_SIZE];
+    out_sha.Finalize(out_sha_bytes);
+    std::string out_sha_hex = HexStr(std::begin(out_sha_bytes), std::end(out_sha_bytes));
+
+    // If check below fails, should manually dump the results with:
+    //
+    //   CHAIN_MERGE_TEST_OUT=results.txt ./test_bitcoin --run_test=util_tests/util_ChainMerge
+    //
+    // And verify diff against previous results to make sure the changes are expected.
+    //
+    // Results file is formatted like:
+    //
+    //   <input> || <output>
+    BOOST_CHECK_EQUAL(out_sha_hex, "b284f4b4a15dd6bf8c06213a69a004b1960388e1d9917173927db52ac220927f");
+}
+
 BOOST_AUTO_TEST_CASE(util_FormatMoney)
 {
     BOOST_CHECK_EQUAL(FormatMoney(0), "0.00");