1 files changed, 112 insertions, 0 deletions
diff --git a/tests/test_buffer.py b/tests/test_buffer.py
new file mode 100644
index 0000000..e636137
--- /dev/null
+++ b/tests/test_buffer.py
@@ -0,0 +1,112 @@
+from __future__ import annotations
+
+import pytest
+
+from prompt_toolkit.buffer import Buffer
+
+
+@pytest.fixture
+def _buffer():
+    buff = Buffer()
+    return buff
+
+
+def test_initial(_buffer):
+    assert _buffer.text == ""
+    assert _buffer.cursor_position == 0
+
+
+def test_insert_text(_buffer):
+    _buffer.insert_text("some_text")
+    assert _buffer.text == "some_text"
+    assert _buffer.cursor_position == len("some_text")
+
+
+def test_cursor_movement(_buffer):
+    _buffer.insert_text("some_text")
+    _buffer.cursor_left()
+    _buffer.cursor_left()
+    _buffer.cursor_left()
+    _buffer.cursor_right()
+    _buffer.insert_text("A")
+
+    assert _buffer.text == "some_teAxt"
+    assert _buffer.cursor_position == len("some_teA")
+
+
+def test_backspace(_buffer):
+    _buffer.insert_text("some_text")
+    _buffer.cursor_left()
+    _buffer.cursor_left()
+    _buffer.delete_before_cursor()
+
+    assert _buffer.text == "some_txt"
+    assert _buffer.cursor_position == len("some_t")
+
+
+def test_cursor_up(_buffer):
+    # Cursor up to a line thats longer.
+    _buffer.insert_text("long line1\nline2")
+    _buffer.cursor_up()
+
+    assert _buffer.document.cursor_position == 5
+
+    # Going up when already at the top.
+    _buffer.cursor_up()
+    assert _buffer.document.cursor_position == 5
+
+    # Going up to a line that's shorter.
+    _buffer.reset()
+    _buffer.insert_text("line1\nlong line2")
+
+    _buffer.cursor_up()
+    assert _buffer.document.cursor_position == 5
+
+
+def test_cursor_down(_buffer):
+    _buffer.insert_text("line1\nline2")
+    _buffer.cursor_position = 3
+
+    # Normally going down
+    _buffer.cursor_down()
+    assert _buffer.document.cursor_position == len("line1\nlin")
+
+    # Going down to a line that's shorter.
+    _buffer.reset()
+    _buffer.insert_text("long line1\na\nb")
+    _buffer.cursor_position = 3
+
+    _buffer.cursor_down()
+    assert _buffer.document.cursor_position == len("long line1\na")
+
+
+def test_join_next_line(_buffer):
+    _buffer.insert_text("line1\nline2\nline3")
+    _buffer.cursor_up()
+    _buffer.join_next_line()
+
+    assert _buffer.text == "line1\nline2 line3"
+
+    # Test when there is no '\n' in the text
+    _buffer.reset()
+    _buffer.insert_text("line1")
+    _buffer.cursor_position = 0
+    _buffer.join_next_line()
+
+    assert _buffer.text == "line1"
+
+
+def test_newline(_buffer):
+    _buffer.insert_text("hello world")
+    _buffer.newline()
+
+    assert _buffer.text == "hello world\n"
+
+
+def test_swap_characters_before_cursor(_buffer):
+    _buffer.insert_text("hello world")
+    _buffer.cursor_left()
+    _buffer.cursor_left()
+    _buffer.swap_characters_before_cursor()
+
+    assert _buffer.text == "hello wrold"