add basic unit tests run at startup

src/main.cc

@@ -903,6 +903,8 @@ void exec_string(const CommandParameters& params,
     exec_keys(keys, context);
 }
 
+void run_unit_tests();
+
 int main(int argc, char* argv[])
 {
     NCurses::init(prompt_func, get_key_func);
@@ -914,6 +916,8 @@ int main(int argc, char* argv[])
     FilterRegistry      filter_registry;
     GlobalHooksManager  hooks_manager;
 
+    run_unit_tests();
+
     command_manager.register_commands({ "e", "edit" }, edit<false>,
                                      CommandManager::None,
                                      PerArgumentCommandCompleter({ complete_filename }));

src/unit_tests.cc

@@ -0,0 +1,33 @@
+#include "buffer.hh"
+#include "assert.hh"
+
+using namespace Kakoune;
+
+int test_buffer()
+{
+    Buffer buffer("test", Buffer::Type::Scratch, "allo ?\nmais que fais la police\n hein ?\n youpi\n");
+    assert(buffer.line_count() == 4);
+
+    BufferIterator i = buffer.begin();
+    assert(*i == 'a');
+    i += 6;
+    assert(buffer.line_and_column_at(i) == BufferCoord{0 COMMA 6});
+    i += 1;
+    assert(buffer.line_and_column_at(i) == BufferCoord{1 COMMA 0});
+    --i;
+    assert(buffer.line_and_column_at(i) == BufferCoord{0 COMMA 6});
+    ++i;
+    assert(buffer.line_and_column_at(i) == BufferCoord{1 COMMA 0});
+    buffer.modify(Modification::make_insert(i, "tchou kanaky\n"));
+    assert(buffer.line_count() == 5);
+
+    BufferIterator begin = buffer.iterator_at({ 4, 1 });
+    BufferIterator end = buffer.iterator_at({ 4, 5 }) + 1;
+    String str = buffer.string(begin, end);
+    assert(str == "youpi");
+}
+
+void run_unit_tests()
+{
+    test_buffer();
+}