WIP: checkpoint geocaching before main integration

modules/core_geocaching/tests/test_buffered.cpp

@@ -0,0 +1,34 @@
+#include "gps/gpx/buffered_sink.h"
+#include <cassert>
+#include <memory>
+#include <string>
+struct Sink : gps::gpx::OutputSink
+{
+    std::string data;
+    unsigned writes = 0;
+    bool fail = false;
+    bool write(std::string_view bytes) override
+    {
+        ++writes;
+        if (fail) return false;
+        data.append(bytes);
+        return true;
+    }
+};
+int main()
+{
+    Sink sink;
+    auto buffered = std::make_unique<gps::gpx::BufferedOutputSink>(sink);
+    for (unsigned i = 0; i < 1100; ++i) assert(buffered->write("abc"));
+    assert(sink.writes == 3 && sink.data.size() == 3072);
+    assert(buffered->finish());
+    assert(sink.data.size() == 3300 && sink.writes == 4);
+    for (std::size_t i = 0; i < sink.data.size(); ++i) assert(sink.data[i] == "abc"[i % 3]);
+    assert(buffered->finish() && sink.writes == 4 && !buffered->write("x"));
+    Sink bad;
+    auto failing = std::make_unique<gps::gpx::BufferedOutputSink>(bad);
+    assert(failing->write("x"));
+    bad.fail = true;
+    assert(!failing->finish());
+    assert(!failing->write("y") && !failing->finish());
+}