pytester: testdir: add makefiles helper

This is a sane method to create a set of files, allowing for absolute
paths.

Ref: #6578
Ref: #6579

Author: blueyed

src/_pytest/pytester.py

@@ -7,6 +7,7 @@
 import re
 import subprocess
 import sys
+import textwrap
 import time
 import traceback
 from fnmatch import fnmatch
@@ -665,6 +666,17 @@ def maketxtfile(self, *args, **kwargs):
         """Shortcut for .makefile() with a .txt extension."""
         return self._makefile(".txt", args, kwargs)
 
+    def makefiles(self, **kwargs: str) -> Optional[Path]:
+        """Create the given set of files."""
+        first_path = None
+        for fname, content in kwargs.items():
+            path = Path(self.tmpdir).joinpath(Path(fname))
+            with open(path, "w") as fp:
+                fp.write(textwrap.dedent(content))
+            if not first_path:
+                first_path = path
+        return first_path
+
     def syspathinsert(self, path=None):
         """Prepend a directory to sys.path, defaults to :py:attr:`tmpdir`.
 

testing/test_pytester.py

@@ -11,6 +11,7 @@
 from _pytest.config import PytestPluginManager
 from _pytest.main import ExitCode
 from _pytest.outcomes import Failed
+from _pytest.pathlib import Path
 from _pytest.pytester import CwdSnapshot
 from _pytest.pytester import HookRecorder
 from _pytest.pytester import LineMatcher
@@ -710,3 +711,16 @@ def test_error2(bad_fixture):
     result.assert_outcomes(error=2)
 
     assert result.parseoutcomes() == {"error": 2}
+
+
+def test_testdir_makefiles(testdir: Testdir) -> None:
+    abspath = str(testdir.tmpdir / "bar")
+    p1 = testdir.makefiles(**{"foo": "", abspath: ""})
+    relpath = testdir.tmpdir / "foo"
+    assert p1 == relpath
+
+    abspath_path = Path(abspath)
+    assert abspath_path.exists()
+    assert str(abspath_path) == abspath
+
+    assert testdir.makefiles() is None