Coverage for app/backend/src/tests/test_config.py: 100%

1import typing 

2 

3import pytest 

4 

5from couchers.config import Config 

6from couchers.constants import DB_POOL_SIZE 

7 

8 

9def _complete_config(dev: bool) -> Config: 

10 """Build a config object attribute populated with a valid, truthy value. 

11 

12 This mirrors what Config.load_from_env() produces when every env var is set, 

13 so Config.check() should succeed against it. 

14 """ 

15 cfg = Config() 

16 for var_name, var_type in Config.__annotations__.items(): 

17 if var_type is bool: 

18 setattr(cfg, var_name, True) 

19 elif var_type is int: 

20 setattr(cfg, var_name, 1) 

21 elif var_type is bytes: 

22 setattr(cfg, var_name, b"x") 

23 elif typing.get_origin(var_type) is typing.Literal: # type: ignore[comparison-overlap] 

24 setattr(cfg, var_name, typing.get_args(var_type)[0]) 

25 else: 

26 setattr(cfg, var_name, "x") 

27 

28 cfg.DEV = dev 

29 if not dev: 

30 # production invariants that aren't satisfiable by a generic truthy value 

31 cfg.BASE_URL = "https://example.com" 

32 cfg.ENABLE_EMAIL = True 

33 cfg.IN_TEST = False 

34 cfg.FEATURE_FLAGS_FILE_OVERRIDE_PATH = "" 

35 return cfg 

36 

37 

38def test_load_from_env() -> None: 

39 cfg = Config() 

40 assert not hasattr(cfg, "BASE_URL") 

41 cfg.load_from_env({"BASE_URL": "https://example.com"}) 

42 assert cfg.BASE_URL == "https://example.com" 

43 

44 

45def test_load_from_env_types() -> None: 

46 cfg = Config() 

47 

48 cfg.load_from_env({"IN_TEST": "1"}) 

49 assert cfg.IN_TEST is True 

50 with pytest.raises(ValueError): 

51 cfg.load_from_env({"IN_TEST": "not a bool"}) 

52 

53 cfg.load_from_env({"BACKGROUND_WORKER_PROCESSES": "42"}) 

54 assert cfg.BACKGROUND_WORKER_PROCESSES == 42 

55 with pytest.raises(ValueError): 

56 cfg.load_from_env({"BACKGROUND_WORKER_PROCESSES": "not an int"}) 

57 

58 cfg.load_from_env({"SECRET": bytes.hex(b"abc")}) 

59 assert cfg.SECRET == b"abc" 

60 with pytest.raises(ValueError): 

61 cfg.load_from_env({"SECRET": "not hex"}) 

62 

63 cfg.load_from_env({"ROLE": "worker"}) 

64 assert cfg.ROLE == "worker" 

65 with pytest.raises(ValueError): 

66 cfg.load_from_env({"ROLE": "not a valid role"}) 

67 

68 

69def test_getitem() -> None: 

70 cfg = Config() 

71 cfg.BASE_URL = "https://example.com" 

72 assert cfg.BASE_URL == "https://example.com" 

73 assert cfg["BASE_URL"] == "https://example.com" 

74 

75 

76def test_setitem() -> None: 

77 cfg = Config() 

78 

79 cfg["BASE_URL"] = "https://example.com" 

80 assert cfg.BASE_URL == "https://example.com" 

81 assert cfg["BASE_URL"] == "https://example.com" 

82 

83 with pytest.raises(KeyError): 

84 cfg["NOT_A_KEY"] = "value" 

85 

86 with pytest.raises(TypeError): 

87 cfg["BASE_URL"] = 123 

88 

89 

90def test_instances_state_are_independent() -> None: 

91 # Default values are declared at the class level, but should be copied to each instance. 

92 assert Config.IN_TEST is False 

93 

94 cfg1 = Config() 

95 cfg2 = Config() 

96 

97 assert cfg1.IN_TEST is False 

98 assert cfg2.IN_TEST is False 

99 

100 cfg1.IN_TEST = True 

101 

102 assert cfg1.IN_TEST is True 

103 assert cfg2.IN_TEST is False 

104 

105 

106def test_copy() -> None: 

107 cfg = Config() 

108 

109 cfg.BACKGROUND_WORKER_PROCESSES = 1 

110 copy1 = cfg.copy() 

111 cfg.BACKGROUND_WORKER_PROCESSES = 2 

112 copy2 = cfg.copy() 

113 

114 assert copy1.BACKGROUND_WORKER_PROCESSES == 1 

115 assert copy2.BACKGROUND_WORKER_PROCESSES == 2 

116 

117 

118@pytest.mark.parametrize("dev", [True, False]) 

119def test_check_config_only_references_known_keys(dev): 

120 """Config.check() must only access config keys that are declared as attributes. 

121 

122 A reference to a key that was removed from attributes (e.g. a toggle migrated to a feature 

123 flag) would raise KeyError at app boot but is invisible to the rest of the test suite, since 

124 Config.check() only runs in app.py's startup path. Exercising it here catches that. 

125 """ 

126 _complete_config(dev=dev).check() 

127 

128 

129def test_check_rejects_too_many_worker_threads() -> None: 

130 cfg = _complete_config(dev=True) 

131 cfg.BACKGROUND_WORKER_THREADS_PER_PROCESS = DB_POOL_SIZE // 2 

132 cfg.check() 

133 

134 cfg.BACKGROUND_WORKER_THREADS_PER_PROCESS = DB_POOL_SIZE // 2 + 1 

135 with pytest.raises(Exception, match="BACKGROUND_WORKER_THREADS_PER_PROCESS"): 

136 cfg.check()