test_dictcomps.py 5.1 KB

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  1. import unittest
  2. # For scope testing.
  3. g = "Global variable"
  4. class DictComprehensionTest(unittest.TestCase):
  5. def test_basics(self):
  6. expected = {0: 10, 1: 11, 2: 12, 3: 13, 4: 14, 5: 15, 6: 16, 7: 17,
  7. 8: 18, 9: 19}
  8. actual = {k: k + 10 for k in range(10)}
  9. self.assertEqual(actual, expected)
  10. expected = {0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9}
  11. actual = {k: v for k in range(10) for v in range(10) if k == v}
  12. self.assertEqual(actual, expected)
  13. def test_scope_isolation(self):
  14. k = "Local Variable"
  15. expected = {0: None, 1: None, 2: None, 3: None, 4: None, 5: None,
  16. 6: None, 7: None, 8: None, 9: None}
  17. actual = {k: None for k in range(10)}
  18. self.assertEqual(actual, expected)
  19. self.assertEqual(k, "Local Variable")
  20. expected = {9: 1, 18: 2, 19: 2, 27: 3, 28: 3, 29: 3, 36: 4, 37: 4,
  21. 38: 4, 39: 4, 45: 5, 46: 5, 47: 5, 48: 5, 49: 5, 54: 6,
  22. 55: 6, 56: 6, 57: 6, 58: 6, 59: 6, 63: 7, 64: 7, 65: 7,
  23. 66: 7, 67: 7, 68: 7, 69: 7, 72: 8, 73: 8, 74: 8, 75: 8,
  24. 76: 8, 77: 8, 78: 8, 79: 8, 81: 9, 82: 9, 83: 9, 84: 9,
  25. 85: 9, 86: 9, 87: 9, 88: 9, 89: 9}
  26. actual = {k: v for v in range(10) for k in range(v * 9, v * 10)}
  27. self.assertEqual(k, "Local Variable")
  28. self.assertEqual(actual, expected)
  29. def test_scope_isolation_from_global(self):
  30. expected = {0: None, 1: None, 2: None, 3: None, 4: None, 5: None,
  31. 6: None, 7: None, 8: None, 9: None}
  32. actual = {g: None for g in range(10)}
  33. self.assertEqual(actual, expected)
  34. self.assertEqual(g, "Global variable")
  35. expected = {9: 1, 18: 2, 19: 2, 27: 3, 28: 3, 29: 3, 36: 4, 37: 4,
  36. 38: 4, 39: 4, 45: 5, 46: 5, 47: 5, 48: 5, 49: 5, 54: 6,
  37. 55: 6, 56: 6, 57: 6, 58: 6, 59: 6, 63: 7, 64: 7, 65: 7,
  38. 66: 7, 67: 7, 68: 7, 69: 7, 72: 8, 73: 8, 74: 8, 75: 8,
  39. 76: 8, 77: 8, 78: 8, 79: 8, 81: 9, 82: 9, 83: 9, 84: 9,
  40. 85: 9, 86: 9, 87: 9, 88: 9, 89: 9}
  41. actual = {g: v for v in range(10) for g in range(v * 9, v * 10)}
  42. self.assertEqual(g, "Global variable")
  43. self.assertEqual(actual, expected)
  44. def test_global_visibility(self):
  45. expected = {0: 'Global variable', 1: 'Global variable',
  46. 2: 'Global variable', 3: 'Global variable',
  47. 4: 'Global variable', 5: 'Global variable',
  48. 6: 'Global variable', 7: 'Global variable',
  49. 8: 'Global variable', 9: 'Global variable'}
  50. actual = {k: g for k in range(10)}
  51. self.assertEqual(actual, expected)
  52. def test_local_visibility(self):
  53. v = "Local variable"
  54. expected = {0: 'Local variable', 1: 'Local variable',
  55. 2: 'Local variable', 3: 'Local variable',
  56. 4: 'Local variable', 5: 'Local variable',
  57. 6: 'Local variable', 7: 'Local variable',
  58. 8: 'Local variable', 9: 'Local variable'}
  59. actual = {k: v for k in range(10)}
  60. self.assertEqual(actual, expected)
  61. self.assertEqual(v, "Local variable")
  62. def test_illegal_assignment(self):
  63. with self.assertRaisesRegex(SyntaxError, "cannot assign"):
  64. compile("{x: y for y, x in ((1, 2), (3, 4))} = 5", "<test>",
  65. "exec")
  66. with self.assertRaisesRegex(SyntaxError, "illegal expression"):
  67. compile("{x: y for y, x in ((1, 2), (3, 4))} += 5", "<test>",
  68. "exec")
  69. def test_evaluation_order(self):
  70. expected = {
  71. 'H': 'W',
  72. 'e': 'o',
  73. 'l': 'l',
  74. 'o': 'd',
  75. }
  76. expected_calls = [
  77. ('key', 'H'), ('value', 'W'),
  78. ('key', 'e'), ('value', 'o'),
  79. ('key', 'l'), ('value', 'r'),
  80. ('key', 'l'), ('value', 'l'),
  81. ('key', 'o'), ('value', 'd'),
  82. ]
  83. actual_calls = []
  84. def add_call(pos, value):
  85. actual_calls.append((pos, value))
  86. return value
  87. actual = {
  88. add_call('key', k): add_call('value', v)
  89. for k, v in zip('Hello', 'World')
  90. }
  91. self.assertEqual(actual, expected)
  92. self.assertEqual(actual_calls, expected_calls)
  93. def test_assignment_idiom_in_comprehensions(self):
  94. expected = {1: 1, 2: 4, 3: 9, 4: 16}
  95. actual = {j: j*j for i in range(4) for j in [i+1]}
  96. self.assertEqual(actual, expected)
  97. expected = {3: 2, 5: 6, 7: 12, 9: 20}
  98. actual = {j+k: j*k for i in range(4) for j in [i+1] for k in [j+1]}
  99. self.assertEqual(actual, expected)
  100. expected = {3: 2, 5: 6, 7: 12, 9: 20}
  101. actual = {j+k: j*k for i in range(4) for j, k in [(i+1, i+2)]}
  102. self.assertEqual(actual, expected)
  103. def test_star_expression(self):
  104. expected = {0: 0, 1: 1, 2: 4, 3: 9}
  105. self.assertEqual({i: i*i for i in [*range(4)]}, expected)
  106. self.assertEqual({i: i*i for i in (*range(4),)}, expected)
  107. if __name__ == "__main__":
  108. unittest.main()