Mercurial Repositories > eric / file comparison
comparison: eric6/DebugClients/Python/coverage/optional.py
eric6/DebugClients/Python/coverage/optional.py
- changeset 7427
- 362cd1b6f81a
- child 7975
- 7d493839a8fc
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| 1 # Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0 | |
| 2 # For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt | |
| 3 | |
| 4 """ | |
| 5 Imports that we need at runtime, but might not be present. | |
| 6 | |
| 7 When importing one of these modules, always do it in the function where you | |
| 8 need the module. Some tests will need to remove the module. If you import | |
| 9 it at the top level of your module, then the test won't be able to simulate | |
| 10 the module being unimportable. | |
| 11 | |
| 12 The import will always succeed, but the value will be None if the module is | |
| 13 unavailable. | |
| 14 | |
| 15 Bad:: | |
| 16 | |
| 17 # MyModule.py | |
| 18 from coverage.optional import unsure | |
| 19 | |
| 20 def use_unsure(): | |
| 21 unsure.something() | |
| 22 | |
| 23 Good:: | |
| 24 | |
| 25 # MyModule.py | |
| 26 | |
| 27 def use_unsure(): | |
| 28 from coverage.optional import unsure | |
| 29 if unsure is None: | |
| 30 raise Exception("Module unsure isn't available!") | |
| 31 | |
| 32 unsure.something() | |
| 33 | |
| 34 """ | |
| 35 | |
| 36 import contextlib | |
| 37 | |
| 38 # This file's purpose is to provide modules to be imported from here. | |
| 39 # pylint: disable=unused-import | |
| 40 | |
| 41 # TOML support is an install-time extra option. | |
| 42 try: | |
| 43 import toml | |
| 44 except ImportError: # pragma: not covered | |
| 45 toml = None | |
| 46 | |
| 47 | |
| 48 @contextlib.contextmanager | |
| 49 def without(modname): | |
| 50 """Hide a module for testing. | |
| 51 | |
| 52 Use this in a test function to make an optional module unavailable during | |
| 53 the test:: | |
| 54 | |
| 55 with coverage.optional.without('toml'): | |
| 56 use_toml_somehow() | |
| 57 | |
| 58 Arguments: | |
| 59 modname (str): the name of a module importable from | |
| 60 `coverage.optional`. | |
| 61 | |
| 62 """ | |
| 63 real_module = globals()[modname] | |
| 64 try: | |
| 65 globals()[modname] = None | |
| 66 yield | |
| 67 finally: | |
| 68 globals()[modname] = real_module |
