Add code snipet integration testissue/1393/add-property-based-testing-of-complex-code-snippet

2 files changed, 161 insertions, 0 deletions

diff --git a/tests/integration/conftest.py b/tests/integration/conftest.py
new file mode 100644
index 00000000..e83f690c
--- /dev/null
+++ b/tests/integration/conftest.py
@@ -0,0 +1,51 @@
+import isort
+from hypothesis import strategies as st
+from typing import get_type_hints
+
+
+def _as_config(kw) -> isort.Config:
+    if "wrap_length" in kw and "line_length" in kw:
+        kw["wrap_length"], kw["line_length"] = sorted([kw["wrap_length"], kw["line_length"]])
+    try:
+        return isort.Config(**kw)
+    except ValueError:
+        kw["wrap_length"] = 0
+        return isort.Config(**kw)
+
+
+def configs(**force_strategies: st.SearchStrategy) -> st.SearchStrategy[isort.Config]:
+    """Generate arbitrary Config objects."""
+    skip = {
+        "line_ending",
+        "sections",
+        "known_future_library",
+        "forced_separate",
+        "lines_after_imports",
+        "lines_between_sections",
+        "lines_between_types",
+        "sources",
+        "virtual_env",
+        "conda_env",
+        "directory",
+        "formatter",
+        "formatting_function",
+    }
+    inferred_kwargs = {
+        k: st.from_type(v)
+        for k, v in get_type_hints(isort.settings._Config).items()
+        if k not in skip
+    }
+    specific = {
+        "line_length": st.integers(0, 200),
+        "wrap_length": st.integers(0, 200),
+        "indent": st.integers(0, 20).map(lambda n: n * " "),
+        "default_section": st.sampled_from(sorted(isort.settings.KNOWN_SECTION_MAPPING)),
+        "force_grid_wrap": st.integers(0, 20),
+        "profile": st.sampled_from(sorted(isort.settings.profiles)),
+        "py_version": st.sampled_from(("auto",) + isort.settings.VALID_PY_TARGETS),
+    }
+    kwargs = {**inferred_kwargs, **specific, **force_strategies}
+    return st.fixed_dictionaries({}, optional=kwargs).map(_as_config)
+
+
+st.register_type_strategy(isort.Config, configs())
diff --git a/tests/integration/test_setting_combinations.py b/tests/integration/test_setting_combinations.py
new file mode 100644
index 00000000..c3fae0ee
--- /dev/null
+++ b/tests/integration/test_setting_combinations.py
@@ -0,0 +1,110 @@
+import isort
+import hypothesis
+from hypothesis import find, settings, Verbosity
+from hypothesis import strategies as st
+
+CODE_SNIPPET = """
+''' Taken from bottle.py
+
+Copyright (c) 2009-2018, Marcel Hellkamp.
+License: MIT (see LICENSE for details)
+'''
+# Lots of stdlib and builtin differences.
+if py3k:
+    import http.client as httplib
+    import _thread as thread
+    from urllib.parse import urljoin, SplitResult as UrlSplitResult
+    from urllib.parse import urlencode, quote as urlquote, unquote as urlunquote
+    urlunquote = functools.partial(urlunquote, encoding='latin1')
+    from http.cookies import SimpleCookie, Morsel, CookieError
+    from collections.abc import MutableMapping as DictMixin
+    import pickle # comment number 2
+    from io import BytesIO
+    import configparser
+
+    basestring = str
+    unicode = str
+    json_loads = lambda s: json_lds(touni(s))
+    callable = lambda x: hasattr(x, '__call__')
+    imap = map
+
+    def _raise(*a):
+        raise a[0](a[1]).with_traceback(a[2])
+else:  # 2.x
+    import httplib
+    import thread
+    from urlparse import urljoin, SplitResult as UrlSplitResult
+    from urllib import urlencode, quote as urlquote, unquote as urlunquote
+    from Cookie import SimpleCookie, Morsel, CookieError
+    from itertools import imap
+    import cPickle as pickle
+    from StringIO import StringIO as BytesIO
+    import ConfigParser as configparser  # commentnumberone
+    from collections import MutableMapping as DictMixin
+    unicode = unicode
+    json_loads = json_lds
+    exec(compile('def _raise(*a): raise a[0], a[1], a[2]', '<py3fix>', 'exec'))
+"""
+SHOULD_RETAIN = ["""''' Taken from bottle.py
+
+Copyright (c) 2009-2018, Marcel Hellkamp.
+License: MIT (see LICENSE for details)
+'''""",
+"# Lots of stdlib and builtin differences.",
+"if py3k:",
+"http.client",
+"_thread",
+"urllib.parse",
+"urlencode",
+"urlunquote = functools.partial(urlunquote, encoding='latin1')",
+"http.cookies",
+"SimpleCookie",
+"collections.abc",
+"pickle",
+"# comment number 2",
+"io",
+"configparser",
+"""basestring = str
+    unicode = str
+    json_loads = lambda s: json_lds(touni(s))
+    callable = lambda x: hasattr(x, '__call__')
+    imap = map
+
+    def _raise(*a):
+        raise a[0](a[1]).with_traceback(a[2])
+else:  # 2.x
+""",
+    "httplib",
+    "thread",
+    "urlparse",
+    "urllib",
+    "Cookie",
+    "itertools",
+    "cPickle",
+    "StringIO",
+    "ConfigParser",
+    "commentnumberone",
+    "collections",
+    """unicode = unicode
+    json_loads = json_lds
+    exec(compile('def _raise(*a): raise a[0], a[1], a[2]', '<py3fix>', 'exec'))"""
+]
+
+
+@hypothesis.given(
+    config=st.from_type(isort.Config),
+    disregard_skip=st.booleans(),
+)
+def test_isort_is_idempotent(config: isort.Config, disregard_skip: bool) -> None:
+    result = isort.code(CODE_SNIPPET, config=config, disregard_skip=disregard_skip)
+    assert result == isort.code(result, config=config, disregard_skip=disregard_skip)
+    
+    
+@hypothesis.given(
+    config=st.from_type(isort.Config),
+    disregard_skip=st.booleans(),
+)
+def test_isort_is_doesnt_lose_imports_or_comments(config: isort.Config, disregard_skip: bool) -> None:
+    result = isort.code(CODE_SNIPPET, config=config, disregard_skip=disregard_skip)
+    for should_be_retained in SHOULD_RETAIN:
+        assert should_be_retained in result