port pagination tests

tests/pydis_core/utils/test_pagination.py

@@ -0,0 +1,46 @@
+from unittest import TestCase
+
+from pydis_core.utils import pagination
+
+
+class LinePaginatorTests(TestCase):
+    """Tests functionality of the `LinePaginator`."""
+
+    def setUp(self):
+        """Create a paginator for the test method."""
+        self.paginator = pagination.LinePaginator(prefix="", suffix="", max_size=30,
+                                                  scale_to_size=50)
+
+    def test_add_line_works_on_small_lines(self):
+        """`add_line` should allow small lines to be added."""
+        self.paginator.add_line("x" * (self.paginator.max_size - 3))
+        # Note that the page isn't added to _pages until it's full.
+        self.assertEqual(len(self.paginator._pages), 0)
+
+    def test_add_line_works_on_long_lines(self):
+        """After additional lines after `max_size` is exceeded should go on the next page."""
+        self.paginator.add_line("x" * self.paginator.max_size)
+        self.assertEqual(len(self.paginator._pages), 0)
+
+        # Any additional lines should start a new page after `max_size` is exceeded.
+        self.paginator.add_line("x")
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_continuation(self):
+        """When `scale_to_size` is exceeded, remaining words should be split onto the next page."""
+        self.paginator.add_line("zyz " * (self.paginator.scale_to_size // 4 + 1))
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_no_continuation(self):
+        """If adding a new line to an existing page would exceed `max_size`, it should start a new
+        page rather than using continuation.
+        """
+        self.paginator.add_line("z" * (self.paginator.max_size - 3))
+        self.paginator.add_line("z")
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_truncates_very_long_words(self):
+        """`add_line` should truncate if a single long word exceeds `scale_to_size`."""
+        self.paginator.add_line("x" * (self.paginator.scale_to_size + 1))
+        # Note: item at index 1 is the truncated line, index 0 is prefix
+        self.assertEqual(self.paginator._current_page[1], "x" * self.paginator.scale_to_size)