Add prometheus support (#950)

Fixes #888

unittests/util/prometheus/CounterTests.cpp

@@ -0,0 +1,157 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2023, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <util/prometheus/Counter.h>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <thread>
+
+using namespace util::prometheus;
+
+struct AnyCounterTests : ::testing::Test {
+    struct MockCounterImpl {
+        using ValueType = std::uint64_t;
+        MOCK_METHOD(void, add, (ValueType));
+        MOCK_METHOD(void, set, (ValueType));
+        MOCK_METHOD(ValueType, value, (), (const));
+    };
+
+    ::testing::StrictMock<MockCounterImpl> mockCounterImpl;
+    std::string const name = "test_counter";
+    std::string labelsString = R"({label1="value1",label2="value2"})";
+    CounterInt counter{name, labelsString, static_cast<MockCounterImpl&>(mockCounterImpl)};
+};
+
+TEST_F(AnyCounterTests, name)
+{
+    EXPECT_EQ(counter.name(), name);
+}
+
+TEST_F(AnyCounterTests, labelsString)
+{
+    EXPECT_EQ(counter.labelsString(), labelsString);
+}
+
+TEST_F(AnyCounterTests, serialize)
+{
+    EXPECT_CALL(mockCounterImpl, value()).WillOnce(::testing::Return(42));
+    std::string serialized;
+    counter.serialize(serialized);
+    EXPECT_EQ(serialized, R"(test_counter{label1="value1",label2="value2"} 42)");
+}
+
+TEST_F(AnyCounterTests, operatorAdd)
+{
+    EXPECT_CALL(mockCounterImpl, add(1));
+    ++counter;
+    EXPECT_CALL(mockCounterImpl, add(42));
+    counter += 42;
+}
+
+TEST_F(AnyCounterTests, reset)
+{
+    EXPECT_CALL(mockCounterImpl, set(0));
+    counter.reset();
+}
+
+TEST_F(AnyCounterTests, value)
+{
+    EXPECT_CALL(mockCounterImpl, value()).WillOnce(::testing::Return(42));
+    EXPECT_EQ(counter.value(), 42);
+}
+
+struct CounterIntTests : ::testing::Test {
+    CounterInt counter{"test_counter", R"(label1="value1",label2="value2")"};
+};
+
+TEST_F(CounterIntTests, operatorAdd)
+{
+    ++counter;
+    counter += 24;
+    EXPECT_EQ(counter.value(), 25);
+}
+
+TEST_F(CounterIntTests, reset)
+{
+    ++counter;
+    EXPECT_EQ(counter.value(), 1);
+    counter.reset();
+    EXPECT_EQ(counter.value(), 0);
+}
+
+TEST_F(CounterIntTests, multithreadAdd)
+{
+    static auto constexpr numAdditions = 1000;
+    static auto constexpr numNumberAdditions = 100;
+    static auto constexpr numberToAdd = 11;
+    std::thread thread1([&] {
+        for (int i = 0; i < numAdditions; ++i) {
+            ++counter;
+        }
+    });
+    std::thread thread2([&] {
+        for (int i = 0; i < numNumberAdditions; ++i) {
+            counter += numberToAdd;
+        }
+    });
+    thread1.join();
+    thread2.join();
+    EXPECT_EQ(counter.value(), numAdditions + numNumberAdditions * numberToAdd);
+}
+
+struct CounterDoubleTests : ::testing::Test {
+    CounterDouble counter{"test_counter", R"(label1="value1",label2="value2")"};
+};
+
+TEST_F(CounterDoubleTests, operatorAdd)
+{
+    ++counter;
+    counter += 24.1234;
+    EXPECT_NEAR(counter.value(), 25.1234, 1e-9);
+}
+
+TEST_F(CounterDoubleTests, reset)
+{
+    ++counter;
+    EXPECT_EQ(counter.value(), 1.);
+    counter.reset();
+    EXPECT_EQ(counter.value(), 0.);
+}
+
+TEST_F(CounterDoubleTests, multithreadAdd)
+{
+    static auto constexpr numAdditions = 1000;
+    static auto constexpr numNumberAdditions = 100;
+    static auto constexpr numberToAdd = 11.1234;
+    std::thread thread1([&] {
+        for (int i = 0; i < numAdditions; ++i) {
+            ++counter;
+        }
+    });
+    std::thread thread2([&] {
+        for (int i = 0; i < numNumberAdditions; ++i) {
+            counter += numberToAdd;
+        }
+    });
+    thread1.join();
+    thread2.join();
+    EXPECT_NEAR(counter.value(), numAdditions + numNumberAdditions * numberToAdd, 1e-9);
+}