Added tempfile context manager to FileProxy (fixes #123) (#126)

* added tempfile method

* added test_tempfile

Author: ChrisTimperley

src/rozzy/proxy/file.py

@@ -4,10 +4,12 @@
 """
 __all__ = ('FileProxy',)
 
-from typing import List, Union, Optional, overload
+from typing import List, Union, Iterator, Optional, overload
 from typing_extensions import Literal
 import os
+import contextlib
 import shlex
+import logging
 import tempfile
 import subprocess
 
@@ -16,6 +18,9 @@
 from .shell import ShellProxy
 from ..exceptions import RozzyException
 
+logger: logging.Logger = logging.getLogger(__name__)
+logger.setLevel(logging.DEBUG)
+
 
 class FileProxy:
     def __init__(self,
@@ -365,6 +370,11 @@ def mktemp(self,
             if specified directory does not exist.
         OSError:
             if the temporary file could not be constructed.
+
+        Returns
+        -------
+        str
+            The absolute path of the temporary file.
         """
         template = shlex.quote(f"{prefix if prefix else 'tmp'}.XXXXXXXXXX")
         cmd_parts = ['mktemp', template]
@@ -383,3 +393,31 @@ def mktemp(self,
             raise OSError(f"failed to create temporary directory")
 
         return output
+
+    @contextlib.contextmanager
+    def tempfile(self,
+                 suffix: Optional[str] = None,
+                 prefix: Optional[str] = None,
+                 dirname: Optional[str] = None
+                 ) -> Iterator[str]:
+        """Creates a temporary file within a context.
+
+        Upon exiting the context, the temporary file will be destroyed.
+
+        See Also
+        --------
+        mktemp: Uses the same arguments to create a temporary file.
+
+        Yields
+        ------
+        str
+            The absolute path of the temporary file.
+        """
+        fn = self.mktemp(suffix=suffix, prefix=prefix, dirname=dirname)
+        logger.debug("created temporary file: %s", fn)
+        yield fn
+        logger.debug("destroying temporary file: %s", fn)
+        try:
+            self.remove(fn)
+        except FileNotFoundError:
+            logger.debug("temporary file already destroyed: %s", fn)

test/test_file.py

@@ -352,3 +352,11 @@ def test_mktemp():
         fn = files.mktemp(prefix='foo')
         assert os.path.basename(fn).startswith('foo')
         assert files.isfile(fn)
+
+
+def test_tempfile():
+    with build_file_proxy() as files:
+        fn: str
+        with files.tempfile() as fn:
+            assert files.isfile(fn)
+        assert not files.exists(fn)