test: added test cases for kata 'PaginationHelper'

tests/codewars/test_pagination_helper.py

@@ -0,0 +1,27 @@
+from src.codewars.kata_pagination_helper import PaginationHelper
+
+
+def test_pagination():
+    collection = ["a", "b", "c", "d", "e", "f"]
+    helper = PaginationHelper(collection, 4)
+
+    assert helper.page_count() == 2
+    assert helper.item_count() == 6
+    assert helper.page_item_count(0) == 4
+    assert helper.page_item_count(1) == 2
+    assert helper.page_item_count(2) == -1
+    assert helper.page_index(5) == 1
+    assert helper.page_index(2) == 0
+    assert helper.page_index(20) == -1
+    assert helper.page_index(-10) == -1
+
+    empty = PaginationHelper([], 10)
+
+    assert empty.item_count() == 0
+    assert empty.page_count() == 0
+    assert empty.page_index(0) == -1
+    assert empty.page_index(1) == -1
+    assert empty.page_index(-1) == -1
+    assert empty.page_item_count(0) == -1
+    assert empty.page_item_count(1) == -1
+    assert empty.page_item_count(-1) == -1