Move assert out of prod code

The assert that checks the width of each char is removed from
screen.display and put it into the tests. This ensures that our test
suite maintains the same quality and at the same time we make
screen.display ~x1.7 faster.

Author: eldipa

pyte/screens.py

@@ -256,7 +256,6 @@ def display(self):
                     is_wide_char = False
                     continue
                 char = cell.data
-                assert sum(map(wcwidth, char[1:])) == 0
                 is_wide_char = wcwidth(char[0]) == 2
                 display_line.append(char)
 

tests/helpers/asserts.py

@@ -0,0 +1,12 @@
+from wcwidth import wcwidth
+def consistency_asserts(screen):
+    # Ensure that all the cells in the buffer, if they have
+    # a data of 2 or more code points, they all sum up 0 width
+    # In other words, the width of the cell is determinated by the
+    # width of the first code point.
+    for y in range(screen.lines):
+        for x in range(screen.columns):
+            char = screen.buffer[y][x].data
+            assert sum(map(wcwidth, char[1:])) == 0
+
+

tests/test_history.py

@@ -1,8 +1,10 @@
-import os
+import os, sys
 
 import pyte
 from pyte import control as ctrl, modes as mo
 
+sys.path.append(os.path.join(os.path.dirname(__file__), "helpers"))
+from asserts import consistency_asserts
 
 def chars(history_lines, columns):
     return ["".join(history_lines[y][x].data for x in range(columns))
@@ -96,6 +98,7 @@ def test_prev_page():
         "39  ",
         "    "
     ]
+    consistency_asserts(screen)
 
     assert chars(screen.history.top, screen.columns)[-4:] == [
         "33  ",
@@ -114,6 +117,7 @@ def test_prev_page():
         "37  ",
         "38  "
     ]
+    consistency_asserts(screen)
 
     assert chars(screen.history.top, screen.columns)[-4:] == [
         "31  ",
@@ -138,6 +142,7 @@ def test_prev_page():
         "35  ",
         "36  ",
     ]
+    consistency_asserts(screen)
 
     assert len(screen.history.bottom) == 4
     assert chars(screen.history.bottom, screen.columns) == [
@@ -165,6 +170,7 @@ def test_prev_page():
         "49   ",
         "     "
     ]
+    consistency_asserts(screen)
 
     screen.prev_page()
     assert screen.history.position == 47
@@ -175,6 +181,7 @@ def test_prev_page():
         "46   ",
         "47   "
     ]
+    consistency_asserts(screen)
 
     assert len(screen.history.bottom) == 3
     assert chars(screen.history.bottom, screen.columns) == [
@@ -200,6 +207,7 @@ def test_prev_page():
         "39  ",
         "    "
     ]
+    consistency_asserts(screen)
 
     screen.prev_page()
     assert screen.history.position == 37
@@ -209,6 +217,7 @@ def test_prev_page():
         "36  ",
         "37  "
     ]
+    consistency_asserts(screen)
 
     assert len(screen.history.bottom) == 3
     assert chars(screen.history.bottom, screen.columns) == [
@@ -235,6 +244,7 @@ def test_prev_page():
         "49   ",
         "     "
     ]
+    consistency_asserts(screen)
 
     screen.cursor_to_line(screen.lines // 2)
 
@@ -250,6 +260,7 @@ def test_prev_page():
         "4    ",
         "5    "
     ]
+    consistency_asserts(screen)
 
     while screen.history.position < screen.history.size:
         screen.next_page()
@@ -262,6 +273,7 @@ def test_prev_page():
         "49   ",
         "     "
     ]
+    consistency_asserts(screen)
 
     # e) same with cursor near the middle of the screen.
     screen = pyte.HistoryScreen(5, 5, history=50)
@@ -282,6 +294,7 @@ def test_prev_page():
         "49   ",
         "     "
     ]
+    consistency_asserts(screen)
 
     screen.cursor_to_line(screen.lines // 2 - 2)
 
@@ -297,6 +310,7 @@ def test_prev_page():
         "4    ",
         "5    "
     ]
+    consistency_asserts(screen)
 
     while screen.history.position < screen.history.size:
         screen.next_page()
@@ -310,6 +324,7 @@ def test_prev_page():
         "49   ",
         "     "
     ]
+    consistency_asserts(screen)
 
 
 def test_next_page():
@@ -332,6 +347,7 @@ def test_next_page():
         "24   ",
         "     "
     ]
+    consistency_asserts(screen)
 
     # a) page up -- page down.
     screen.prev_page()
@@ -346,6 +362,7 @@ def test_next_page():
         "24   ",
         "     "
     ]
+    consistency_asserts(screen)
 
     # b) double page up -- page down.
     screen.prev_page()
@@ -366,6 +383,7 @@ def test_next_page():
         "21   ",
         "22   "
     ]
+    consistency_asserts(screen)
 
     # c) double page up -- double page down
     screen.prev_page()
@@ -381,6 +399,7 @@ def test_next_page():
         "21   ",
         "22   "
     ]
+    consistency_asserts(screen)
 
 
 def test_ensure_width(monkeypatch):
@@ -402,6 +421,7 @@ def test_ensure_width(monkeypatch):
         "0024 ",
         "     "
     ]
+    consistency_asserts(screen)
 
     # Shrinking the screen should truncate the displayed lines following lines.
     screen.resize(5, 3)
@@ -416,6 +436,7 @@ def test_ensure_width(monkeypatch):
         "002",  # 21
         "002"   # 22
     ]
+    consistency_asserts(screen)
 
 
 def test_not_enough_lines():
@@ -436,6 +457,7 @@ def test_not_enough_lines():
         "4    ",
         "     "
     ]
+    consistency_asserts(screen)
 
     screen.prev_page()
     assert not screen.history.top
@@ -448,6 +470,7 @@ def test_not_enough_lines():
         "3    ",
         "4    ",
     ]
+    consistency_asserts(screen)
 
     screen.next_page()
     assert screen.history.top
@@ -459,6 +482,7 @@ def test_not_enough_lines():
         "4    ",
         "     "
     ]
+    consistency_asserts(screen)
 
 
 def test_draw(monkeypatch):
@@ -479,6 +503,7 @@ def test_draw(monkeypatch):
         "24   ",
         "     "
     ]
+    consistency_asserts(screen)
 
     # a) doing a pageup and then a draw -- expecting the screen
     #    to scroll to the bottom before drawing anything.
@@ -494,6 +519,7 @@ def test_draw(monkeypatch):
         "24   ",
         "x    "
     ]
+    consistency_asserts(screen)
 
 
 def test_cursor_is_hidden(monkeypatch):

tests/test_input_output.py

@@ -1,5 +1,5 @@
 import json
-import os.path
+import os.path, sys
 
 import pytest
 
@@ -8,6 +8,8 @@
 
 captured_dir = os.path.join(os.path.dirname(__file__), "captured")
 
+sys.path.append(os.path.join(os.path.dirname(__file__), "helpers"))
+from asserts import consistency_asserts
 
 @pytest.mark.parametrize("name", [
     "cat-gpl3", "find-etc", "htop", "ls", "mc", "top", "vi"
@@ -23,3 +25,4 @@ def test_input_output(name):
     stream = pyte.ByteStream(screen)
     stream.feed(input)
     assert screen.display == output
+    consistency_asserts(screen)