Add @files command

Author: GuillaumeGomez

src/etc/htmldocck.py

@@ -110,6 +110,9 @@
 
 * `@has-dir PATH` checks for the existence of the given directory.
 
+* `@files FOLDER_PATH [ENTRIES]`, checks that `FOLDER_PATH` contains exactly
+  `[ENTRIES]`.
+
 All conditions can be negated with `!`. `@!has foo/type.NoSuch.html`
 checks if the given file does not exist, for example.
 
@@ -321,12 +324,15 @@ def resolve_path(self, path):
         else:
             return self.last_path
 
+    def get_absolute_path(self, path):
+        return os.path.join(self.root, path)
+
     def get_file(self, path):
         path = self.resolve_path(path)
         if path in self.files:
             return self.files[path]
 
-        abspath = os.path.join(self.root, path)
+        abspath = self.get_absolute_path(path)
         if not(os.path.exists(abspath) and os.path.isfile(abspath)):
             raise FailedCheck('File does not exist {!r}'.format(path))
 
@@ -340,7 +346,7 @@ def get_tree(self, path):
         if path in self.trees:
             return self.trees[path]
 
-        abspath = os.path.join(self.root, path)
+        abspath = self.get_absolute_path(path)
         if not(os.path.exists(abspath) and os.path.isfile(abspath)):
             raise FailedCheck('File does not exist {!r}'.format(path))
 
@@ -356,7 +362,7 @@ def get_tree(self, path):
 
     def get_dir(self, path):
         path = self.resolve_path(path)
-        abspath = os.path.join(self.root, path)
+        abspath = self.get_absolute_path(path)
         if not(os.path.exists(abspath) and os.path.isdir(abspath)):
             raise FailedCheck('Directory does not exist {!r}'.format(path))
 
@@ -538,6 +544,41 @@ def get_nb_matching_elements(cache, c, regexp, stop_at_first):
         return check_tree_text(cache.get_tree(c.args[0]), pat, c.args[2], regexp, stop_at_first)
 
 
+def check_files_in_folder(c, cache, folder, files):
+    files = files.strip()
+    if not files.startswith('[') or not files.endswith(']'):
+        raise InvalidCheck("Expected list as second argument of @{} (ie '[]')".format(c.cmd))
+
+    folder = cache.get_absolute_path(folder)
+
+    # First we create a set of files to check if there are duplicates.
+    files = shlex.split(files[1:-1].replace(",", ""))
+    files_set = set()
+    for file in files:
+        if file in files_set:
+            raise InvalidCheck("Duplicated file `{}` in @{}".format(file, c.cmd))
+        files_set.add(file)
+    folder_set = set([f for f in os.listdir(folder) if f != "." and f != ".."])
+
+    # Then we remove entries from both sets (we clone `folder_set` so we can iterate it while
+    # removing its elements).
+    for entry in set(folder_set):
+        if entry in files_set:
+            files_set.remove(entry)
+            folder_set.remove(entry)
+
+    error = 0
+    if len(files_set) != 0:
+        print_err(c.lineno, c.context, "Entries not found in folder `{}`: `{}`".format(
+            folder, files_set))
+        error += 1
+    if len(folder_set) != 0:
+        print_err(c.lineno, c.context, "Extra entries in folder `{}`: `{}`".format(
+            folder, folder_set))
+        error += 1
+    return error == 0
+
+
 ERR_COUNT = 0
 
 
@@ -566,6 +607,13 @@ def check_command(c, cache):
             else:
                 raise InvalidCheck('Invalid number of @{} arguments'.format(c.cmd))
 
+        elif c.cmd == 'files': # check files in given folder
+            if len(c.args) != 2: # @files <folder path> <file list>
+                raise InvalidCheck("Invalid number of @{} arguments".format(c.cmd))
+            elif c.negated:
+                raise InvalidCheck("@{} doesn't support negative check".format(c.cmd))
+            ret = check_files_in_folder(c, cache, c.args[0], c.args[1])
+
         elif c.cmd == 'count':  # count test
             if len(c.args) == 3:  # @count <path> <pat> <count> = count test
                 expected = int(c.args[2])