Coverage for /home/martinb/.local/share/virtualenvs/camcops/lib/python3.6/site-packages/_pytest/assertion/__init__.py : 13%

Hot-keys on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
1"""
2support for presenting detailed information in failing assertions.
3"""
4import sys
5from typing import Any
6from typing import Generator
7from typing import List
8from typing import Optional
10from _pytest.assertion import rewrite
11from _pytest.assertion import truncate
12from _pytest.assertion import util
13from _pytest.assertion.rewrite import assertstate_key
14from _pytest.compat import TYPE_CHECKING
15from _pytest.config import Config
16from _pytest.config import hookimpl
17from _pytest.config.argparsing import Parser
18from _pytest.nodes import Item
20if TYPE_CHECKING:
21 from _pytest.main import Session
24def pytest_addoption(parser: Parser) -> None:
25 group = parser.getgroup("debugconfig")
26 group.addoption(
27 "--assert",
28 action="store",
29 dest="assertmode",
30 choices=("rewrite", "plain"),
31 default="rewrite",
32 metavar="MODE",
33 help=(
34 "Control assertion debugging tools.\n"
35 "'plain' performs no assertion debugging.\n"
36 "'rewrite' (the default) rewrites assert statements in test modules"
37 " on import to provide assert expression information."
38 ),
39 )
40 parser.addini(
41 "enable_assertion_pass_hook",
42 type="bool",
43 default=False,
44 help="Enables the pytest_assertion_pass hook."
45 "Make sure to delete any previously generated pyc cache files.",
46 )
49def register_assert_rewrite(*names: str) -> None:
50 """Register one or more module names to be rewritten on import.
52 This function will make sure that this module or all modules inside
53 the package will get their assert statements rewritten.
54 Thus you should make sure to call this before the module is
55 actually imported, usually in your __init__.py if you are a plugin
56 using a package.
58 :raise TypeError: if the given module names are not strings.
59 """
60 for name in names:
61 if not isinstance(name, str):
62 msg = "expected module names as *args, got {0} instead"
63 raise TypeError(msg.format(repr(names)))
64 for hook in sys.meta_path:
65 if isinstance(hook, rewrite.AssertionRewritingHook):
66 importhook = hook
67 break
68 else:
69 # TODO(typing): Add a protocol for mark_rewrite() and use it
70 # for importhook and for PytestPluginManager.rewrite_hook.
71 importhook = DummyRewriteHook() # type: ignore
72 importhook.mark_rewrite(*names)
75class DummyRewriteHook:
76 """A no-op import hook for when rewriting is disabled."""
78 def mark_rewrite(self, *names: str) -> None:
79 pass
82class AssertionState:
83 """State for the assertion plugin."""
85 def __init__(self, config: Config, mode) -> None:
86 self.mode = mode
87 self.trace = config.trace.root.get("assertion")
88 self.hook = None # type: Optional[rewrite.AssertionRewritingHook]
91def install_importhook(config: Config) -> rewrite.AssertionRewritingHook:
92 """Try to install the rewrite hook, raise SystemError if it fails."""
93 config._store[assertstate_key] = AssertionState(config, "rewrite")
94 config._store[assertstate_key].hook = hook = rewrite.AssertionRewritingHook(config)
95 sys.meta_path.insert(0, hook)
96 config._store[assertstate_key].trace("installed rewrite import hook")
98 def undo() -> None:
99 hook = config._store[assertstate_key].hook
100 if hook is not None and hook in sys.meta_path:
101 sys.meta_path.remove(hook)
103 config.add_cleanup(undo)
104 return hook
107def pytest_collection(session: "Session") -> None:
108 # this hook is only called when test modules are collected
109 # so for example not in the master process of pytest-xdist
110 # (which does not collect test modules)
111 assertstate = session.config._store.get(assertstate_key, None)
112 if assertstate:
113 if assertstate.hook is not None:
114 assertstate.hook.set_session(session)
117@hookimpl(tryfirst=True, hookwrapper=True)
118def pytest_runtest_protocol(item: Item) -> Generator[None, None, None]:
119 """Setup the pytest_assertrepr_compare and pytest_assertion_pass hooks
121 The rewrite module will use util._reprcompare if
122 it exists to use custom reporting via the
123 pytest_assertrepr_compare hook. This sets up this custom
124 comparison for the test.
125 """
127 ihook = item.ihook
129 def callbinrepr(op, left: object, right: object) -> Optional[str]:
130 """Call the pytest_assertrepr_compare hook and prepare the result
132 This uses the first result from the hook and then ensures the
133 following:
134 * Overly verbose explanations are truncated unless configured otherwise
135 (eg. if running in verbose mode).
136 * Embedded newlines are escaped to help util.format_explanation()
137 later.
138 * If the rewrite mode is used embedded %-characters are replaced
139 to protect later % formatting.
141 The result can be formatted by util.format_explanation() for
142 pretty printing.
143 """
144 hook_result = ihook.pytest_assertrepr_compare(
145 config=item.config, op=op, left=left, right=right
146 )
147 for new_expl in hook_result:
148 if new_expl:
149 new_expl = truncate.truncate_if_required(new_expl, item)
150 new_expl = [line.replace("\n", "\\n") for line in new_expl]
151 res = "\n~".join(new_expl)
152 if item.config.getvalue("assertmode") == "rewrite":
153 res = res.replace("%", "%%")
154 return res
155 return None
157 saved_assert_hooks = util._reprcompare, util._assertion_pass
158 util._reprcompare = callbinrepr
160 if ihook.pytest_assertion_pass.get_hookimpls():
162 def call_assertion_pass_hook(lineno: int, orig: str, expl: str) -> None:
163 ihook.pytest_assertion_pass(item=item, lineno=lineno, orig=orig, expl=expl)
165 util._assertion_pass = call_assertion_pass_hook
167 yield
169 util._reprcompare, util._assertion_pass = saved_assert_hooks
172def pytest_sessionfinish(session: "Session") -> None:
173 assertstate = session.config._store.get(assertstate_key, None)
174 if assertstate:
175 if assertstate.hook is not None:
176 assertstate.hook.set_session(None)
179def pytest_assertrepr_compare(
180 config: Config, op: str, left: Any, right: Any
181) -> Optional[List[str]]:
182 return util.assertrepr_compare(config=config, op=op, left=left, right=right)