diff --git a/test/src/test_BufferLineWalker.cc b/test/src/test_BufferLineWalker.cc
new file mode 100644
index 0000000..6491ede
--- /dev/null
+++ b/test/src/test_BufferLineWalker.cc
@@ -0,0 +1,180 @@
+#include "gtest/gtest.h"
+#include "BufferLineWalker.h"
+
+class MyCharacterWidthDeterminer : public CharacterWidthDeterminer
+{
+    int operator()(uint32_t character)
+    {
+        if (character < 32)
+        {
+            return 2;
+        }
+        else
+        {
+            return 1;
+        }
+    }
+} cld;
+
+TEST(BufferLineWalkerTest, calls_callback_once_for_empty_line)
+{
+    static const uint8_t data[] = "\n";
+    std::shared_ptr<Buffer> b = std::make_shared<Buffer>(data, 1u);
+    BufferLineWalker blw(b, cld);
+    blw.set_width(20);
+    std::shared_ptr<Buffer::Iterator> start_of_line = b->add_iterator();
+    int times_called = 0;
+    blw.walk_line(*start_of_line, [&times_called](int row_offset, int screen_column, int virtual_column, int character_width, const Buffer::Iterator & it) -> bool {
+            times_called++;
+            EXPECT_EQ(0, row_offset);
+            EXPECT_EQ(0, screen_column);
+            EXPECT_EQ(0, virtual_column);
+            EXPECT_EQ(0, character_width);
+            return true;
+    });
+    EXPECT_EQ(1, times_called);
+}
+
+TEST(BufferLineWalkerTest, walks_correctly_with_tabs_and_no_line_wrapping)
+{
+    static const char data[] = "\t1\t12\t123\t1234\t!";
+    std::shared_ptr<Buffer> b = std::make_shared<Buffer>((const uint8_t *)data, strlen(data));
+    BufferLineWalker blw(b, cld);
+    blw.set_width(100);
+    std::shared_ptr<Buffer::Iterator> start_of_line = b->add_iterator();
+    int times_called = 0;
+    blw.walk_line(*start_of_line, [&times_called](int row_offset, int screen_column, int virtual_column, int character_width, const Buffer::Iterator & it) -> bool {
+            EXPECT_EQ(0, row_offset);
+            static int expected_screen_columns[] = {
+                0,   4, 5,   8, 9, 10,   12, 13, 14, 15,   16, 17, 18, 19, 20,   24, 25
+            };
+            static int expected_character_widths[] = {
+                4,   1, 3,   1, 1, 2,    1, 1, 1, 1,       1, 1, 1, 1, 4,        1, 0
+            };
+            EXPECT_LT(times_called, (int)(sizeof(expected_screen_columns)/sizeof(expected_screen_columns[0])));
+            EXPECT_EQ(expected_screen_columns[times_called], screen_column);
+            EXPECT_EQ(expected_screen_columns[times_called], virtual_column);
+            EXPECT_EQ(expected_character_widths[times_called], character_width);
+            times_called++;
+            return true;
+    });
+    EXPECT_EQ((int)strlen(data) + 1, times_called);
+}
+
+TEST(BufferLineWalkerTest, walks_correctly_with_tabs_and_line_wrapping)
+{
+    static const char data[] = "\t1\t12\t123\t1234\t!";
+    std::shared_ptr<Buffer> b = std::make_shared<Buffer>((const uint8_t *)data, strlen(data));
+    BufferLineWalker blw(b, cld);
+    blw.set_width(5);
+    std::shared_ptr<Buffer::Iterator> start_of_line = b->add_iterator();
+    int times_called = 0;
+    blw.walk_line(*start_of_line, [&times_called](int row_offset, int screen_column, int virtual_column, int character_width, const Buffer::Iterator & it) -> bool {
+            static int expected_screen_columns[] = {
+                0,   4, 0,   3, 4, 0,   2, 3, 4, 0,   1, 2, 3, 4, 0,   4, 0
+            };
+            static int expected_row_offsets[] = {
+                0,   0, 1,   1, 1, 2,   2, 2, 2, 3,   3, 3, 3, 3, 4,   4, 5
+            };
+            static int expected_virtual_columns[] = {
+                0,   4, 5,   8, 9, 10,   12, 13, 14, 15,   16, 17, 18, 19, 20,   24, 25
+            };
+            static int expected_character_widths[] = {
+                4,   1, 3,   1, 1, 2,    1, 1, 1, 1,       1, 1, 1, 1, 4,        1, 0
+            };
+            EXPECT_LT(times_called, (int)(sizeof(expected_screen_columns)/sizeof(expected_screen_columns[0])));
+            EXPECT_EQ(expected_row_offsets[times_called], row_offset);
+            EXPECT_EQ(expected_screen_columns[times_called], screen_column);
+            EXPECT_EQ(expected_virtual_columns[times_called], virtual_column);
+            EXPECT_EQ(expected_character_widths[times_called], character_width);
+            times_called++;
+            return true;
+    });
+    EXPECT_EQ((int)strlen(data) + 1, times_called);
+}
+
+TEST(BufferLineWalkerTest, walks_correctly_with_multi_column_characters_and_line_wrapping)
+{
+    static const char data[] = "ab\002xyz\003.";
+    std::shared_ptr<Buffer> b = std::make_shared<Buffer>((const uint8_t *)data, strlen(data));
+    BufferLineWalker blw(b, cld);
+    blw.set_width(4);
+    std::shared_ptr<Buffer::Iterator> start_of_line = b->add_iterator();
+    int times_called = 0;
+    blw.walk_line(*start_of_line, [&times_called](int row_offset, int screen_column, int virtual_column, int character_width, const Buffer::Iterator & it) -> bool {
+            static int expected_screen_columns[] = {
+                0, 1, 2,  0, 1, 2,  0, 2,  3
+            };
+            static int expected_row_offsets[] = {
+                0, 0, 0,  1, 1, 1,  2, 2,  2
+            };
+            static int expected_virtual_columns[] = {
+                0, 1, 2,  4, 5, 6,  7, 9, 10
+            };
+            static int expected_character_widths[] = {
+                1, 1, 2,  1, 1, 1,  2, 1, 0
+            };
+            EXPECT_LT(times_called, (int)(sizeof(expected_screen_columns)/sizeof(expected_screen_columns[0])));
+            EXPECT_EQ(expected_row_offsets[times_called], row_offset);
+            EXPECT_EQ(expected_screen_columns[times_called], screen_column);
+            EXPECT_EQ(expected_virtual_columns[times_called], virtual_column);
+            EXPECT_EQ(expected_character_widths[times_called], character_width);
+            times_called++;
+            return true;
+    });
+    EXPECT_EQ((int)strlen(data) + 1, times_called);
+}
+
+TEST(BufferLineWalkerTest, does_not_push_down_a_row_when_a_multi_column_character_is_wider_than_view_width)
+{
+    static const char data[] = "\002\003";
+    std::shared_ptr<Buffer> b = std::make_shared<Buffer>((const uint8_t *)data, strlen(data));
+    BufferLineWalker blw(b, cld);
+    blw.set_width(1);
+    std::shared_ptr<Buffer::Iterator> start_of_line = b->add_iterator();
+    int times_called = 0;
+    blw.walk_line(*start_of_line, [&times_called](int row_offset, int screen_column, int virtual_column, int character_width, const Buffer::Iterator & it) -> bool {
+            static int expected_screen_columns[] = {
+                0, 0, 0
+            };
+            static int expected_row_offsets[] = {
+                0, 1, 2
+            };
+            static int expected_virtual_columns[] = {
+                0, 2, 4
+            };
+            static int expected_character_widths[] = {
+                2, 2, 0
+            };
+            EXPECT_LT(times_called, (int)(sizeof(expected_screen_columns)/sizeof(expected_screen_columns[0])));
+            EXPECT_EQ(expected_row_offsets[times_called], row_offset);
+            EXPECT_EQ(expected_screen_columns[times_called], screen_column);
+            EXPECT_EQ(expected_virtual_columns[times_called], virtual_column);
+            EXPECT_EQ(expected_character_widths[times_called], character_width);
+            times_called++;
+            return true;
+    });
+    EXPECT_EQ((int)strlen(data) + 1, times_called);
+}
+
+TEST(BufferLineWalkerTest, stops_iterating_when_callback_returns_false)
+{
+    static const char data[] = "abcdef";
+    std::shared_ptr<Buffer> b = std::make_shared<Buffer>((const uint8_t *)data, strlen(data));
+    BufferLineWalker blw(b, cld);
+    blw.set_width(6);
+    std::shared_ptr<Buffer::Iterator> start_of_line = b->add_iterator();
+    int times_called = 0;
+    blw.walk_line(*start_of_line, [&times_called](int row_offset, int screen_column, int virtual_column, int character_width, const Buffer::Iterator & it) -> bool {
+            times_called++;
+            if (times_called >= 3)
+            {
+                return false;
+            }
+            else
+            {
+                return true;
+            }
+    });
+    EXPECT_EQ(3, times_called);
+}