Add settings_tests

Co-authored-by: James O'Beirne <james.obeirne@gmail.com>

src/Makefile.test.include

@@ -134,6 +134,7 @@ BITCOIN_TESTS =\
   test/script_standard_tests.cpp \
   test/scriptnum_tests.cpp \
   test/serialize_tests.cpp \
+  test/settings_tests.cpp \
   test/sighash_tests.cpp \
   test/sigopcount_tests.cpp \
   test/skiplist_tests.cpp \

src/test/settings_tests.cpp

@@ -0,0 +1,159 @@
+// Copyright (c) 2011-2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <util/settings.h>
+
+#include <test/setup_common.h>
+#include <test/util.h>
+
+#include <boost/test/unit_test.hpp>
+#include <univalue.h>
+#include <util/strencodings.h>
+#include <vector>
+
+BOOST_FIXTURE_TEST_SUITE(settings_tests, BasicTestingSetup)
+
+// Simple settings merge test case.
+BOOST_AUTO_TEST_CASE(Simple)
+{
+    util::Settings settings;
+    settings.command_line_options["name"].push_back("val1");
+    settings.command_line_options["name"].push_back("val2");
+    settings.ro_config["section"]["name"].push_back(2);
+
+    auto check_values = [&](util::Settings s, std::string single_val, std::string list_val) {
+        util::SettingsValue single_value = GetSetting(s, "section", "name", false, false);
+        util::SettingsValue list_value(util::SettingsValue::VARR);
+        for (const auto& item : GetListSetting(s, "section", "name", false)) {
+            list_value.push_back(item);
+        }
+        BOOST_CHECK_EQUAL(single_value.write().c_str(), single_val);
+        BOOST_CHECK_EQUAL(list_value.write().c_str(), list_val);
+    };
+
+    // The last given arg takes precedence when specified via commandline.
+    check_values(settings, R"("val2")", R"(["val1","val2",2])");
+
+    util::Settings settings2;
+    settings2.ro_config["section"]["name"].push_back("val2");
+    settings2.ro_config["section"]["name"].push_back("val3");
+
+    // The first given arg takes precedence when specified via config file.
+    check_values(settings2, R"("val2")", R"(["val2","val3"])");
+}
+
+// Test different ways settings can be merged, and verify results. This test can
+// be used to confirm that updates to settings code don't change behavior
+// unintentionally.
+struct MergeTestingSetup : 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;
+
+    enum Action { END, SET, NEGATE, SECTION_SET, SECTION_NEGATE };
+    using ActionList = Action[MAX_ACTIONS];
+
+    //! Enumerate all possible test configurations.
+    template <typename Fn>
+    void ForEachMergeSetup(Fn&& fn)
+    {
+        ActionList arg_actions = {};
+        ForEachNoDup(arg_actions, SET, NEGATE, [&]{
+            ActionList conf_actions = {};
+            ForEachNoDup(conf_actions, SET, SECTION_NEGATE, [&]{
+                for (bool force_set : {false, true}) {
+                    for (bool ignore_default_section_config : {false, true}) {
+                        fn(arg_actions, conf_actions, force_set, ignore_default_section_config);
+                    }
+                }
+            });
+        });
+    }
+};
+
+// Regression test covering different ways config settings can be merged. The
+// 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(Merge, MergeTestingSetup)
+{
+    CHash256 out_sha;
+    FILE* out_file = nullptr;
+    if (const char* out_path = getenv("SETTINGS_MERGE_TEST_OUT")) {
+        out_file = fsbridge::fopen(out_path, "w");
+        if (!out_file) throw std::system_error(errno, std::generic_category(), "fopen failed");
+    }
+
+    const std::string& network = CBaseChainParams::MAIN;
+    ForEachMergeSetup([&](const ActionList& arg_actions, const ActionList& conf_actions, bool force_set,
+                          bool ignore_default_section_config) {
+        std::string desc;
+        int value_suffix = 0;
+        util::Settings settings;
+
+        const std::string& name = ignore_default_section_config ? "wallet" : "server";
+        auto push_values = [&](Action action, const char* value_prefix, const std::string& name_prefix,
+                               std::vector<util::SettingsValue>& dest) {
+            if (action == SET || action == SECTION_SET) {
+                for (int i = 0; i < 2; ++i) {
+                    dest.push_back(value_prefix + std::to_string(++value_suffix));
+                    desc += " " + name_prefix + name + "=" + dest.back().get_str();
+                }
+            } else if (action == NEGATE || action == SECTION_NEGATE) {
+                dest.push_back(false);
+                desc += " " + name_prefix + "no" + name;
+            }
+        };
+
+        if (force_set) {
+            settings.forced_settings[name] = "forced";
+            desc += " " + name + "=forced";
+        }
+        for (Action arg_action : arg_actions) {
+            push_values(arg_action, "a", "-", settings.command_line_options[name]);
+        }
+        for (Action conf_action : conf_actions) {
+            bool use_section = conf_action == SECTION_SET || conf_action == SECTION_NEGATE;
+            push_values(conf_action, "c", use_section ? network + "." : "",
+                settings.ro_config[use_section ? network : ""][name]);
+        }
+
+        desc += " || ";
+        desc += GetSetting(settings, network, name, ignore_default_section_config, /* skip_nonpersistent= */ false).write();
+        desc += " |";
+        for (const auto& s : GetListSetting(settings, network, name, ignore_default_section_config)) {
+            desc += " ";
+            desc += s.write();
+        }
+        if (HasIgnoredDefaultSectionConfigValue(settings, network, name)) desc += " | ignored";
+        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:
+    //
+    //   SETTINGS_MERGE_TEST_OUT=results.txt ./test_bitcoin --run_test=settings_tests/Merge
+    //
+    // 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, "ec71b35fb64821e6ab4595b1bf8525dc1984258651cfa641f5f6239424914ddb");
+}
+
+BOOST_AUTO_TEST_SUITE_END()