FTL: Add std::variant matcher
Bug: 185536303
Test: ftl_test
Change-Id: Id6357fa04ffe0c17b17c99b49b5a5262d68925bf
diff --git a/libs/ftl/match_test.cpp b/libs/ftl/match_test.cpp
new file mode 100644
index 0000000..a6cff2e
--- /dev/null
+++ b/libs/ftl/match_test.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * 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 <ftl/match.h>
+#include <gtest/gtest.h>
+
+#include <chrono>
+#include <string>
+#include <variant>
+
+namespace android::test {
+
+// Keep in sync with example usage in header file.
+TEST(Match, Example) {
+ using namespace std::chrono;
+ using namespace std::chrono_literals;
+ using namespace std::string_literals;
+
+ std::variant<seconds, minutes, hours> duration = 119min;
+
+ // Mutable match.
+ ftl::match(duration, [](auto& d) { ++d; });
+
+ // Immutable match. Exhaustive due to minutes being convertible to seconds.
+ EXPECT_EQ("2 hours"s,
+ ftl::match(
+ duration,
+ [](const seconds& s) {
+ const auto h = duration_cast<hours>(s);
+ return std::to_string(h.count()) + " hours"s;
+ },
+ [](const hours& h) { return std::to_string(h.count() / 24) + " days"s; }));
+}
+
+} // namespace android::test