add unit tests for buffer insert/erase character

src/core/Buffer.cc

@@ -8,39 +8,47 @@
 
 Buffer::Buffer()
 {
+    common_pre_load_initialization();
     load_empty_buffer();
-    common_initialization();
+    common_post_load_initialization();
 }
 
 Buffer::Buffer(const char * filename)
 {
+    common_pre_load_initialization();
     if (!load_from_file(filename))
     {
         load_empty_buffer();
     }
-    common_initialization();
+    common_post_load_initialization();
 }
 
 Buffer::Buffer(const uint8_t * data, size_t data_length)
 {
+    common_pre_load_initialization();
     if (!load_from_memory(data, data_length))
     {
         load_empty_buffer();
     }
-    common_initialization();
+    common_post_load_initialization();
 }
 
-void Buffer::common_initialization()
+void Buffer::common_pre_load_initialization()
 {
     m_tabstop = 4u;
+    m_change_buffer = std::make_shared<GapBuffer>();
+    m_operation_level = 0;
+    m_current_change_operation_index = INVALID_CHANGE_OPERATION_INDEX;
+    m_encoding = Encoding::UTF_8;
+}
+
+void Buffer::common_post_load_initialization()
+{
     m_eof_iterator = add_iterator();
     while (m_eof_iterator->valid())
     {
         m_eof_iterator->go_forward();
     }
-    m_change_buffer = std::make_shared<GapBuffer>();
-    m_operation_level = 0;
-    m_current_change_operation_index = INVALID_CHANGE_OPERATION_INDEX;
 }
 
 void Buffer::load_empty_buffer()

src/core/Buffer.h

@@ -154,7 +154,8 @@ protected:
     size_t m_current_change_operation_index;
     std::vector<std::shared_ptr<ChangeOperation>> m_change_operations;
 
-    void common_initialization();
+    void common_pre_load_initialization();
+    void common_post_load_initialization();
     bool load_from_file(const char * filename);
     void load_empty_buffer();
     bool load_from_memory(const uint8_t * data, size_t data_length);