Add class for existing files

src/jcloud_docsgen/utils.py

@@ -24,7 +24,7 @@ import types
 
 class ExistingDirectory(pathlib.Path):
     '''
-    pathlib.Path subclass that is a directory
+    pathlib.Path subclass that is a directory.
 
     ExistingDirectory represents a filesystem path but it also checks
     whether the path exists and is not a file but a directory. It
@@ -37,6 +37,21 @@ class ExistingDirectory(pathlib.Path):
             raise NotADirectoryError(errno.ENOTDIR, 'not a directory', path)
         super().__init__(*(path, *args), **kwargs)
 
+class ExistingFile(pathlib.Path):
+    '''
+    pathlib.Path subclass that is a file.
+
+    ExistingFile represents a filesystem path but it also checks whether
+    the path exists and is not a directory but a file. It inherits from
+    pathlib.Path.
+    '''
+    def __init__(self, path, *args, **kwargs) -> None:
+        if not os.path.exists(path):
+            raise FileNotFoundError(errno.ENOENT, 'no such file or directory', path)
+        if not os.path.isfile(path):
+            raise IsADirectoryError(errno.EISDIR, 'is a directory', path)
+        super().__init__(*(path, *args), **kwargs)
+
 def _quote(string: str, quotation_mark: str) -> str:
     '''
     Quotes a string.