rename execute_command to __call__

This commit addresses reviewer comment:
<datalad#596 (comment)>
It renames `ShellCommandExecutor.execute_command` to
`ShellCommandExecutor.__call__`. With that change the
following code becomes possible:

>>> with shell_connection(['bash']) as shell:
...     r = shell(b'uname')

datalad_next/utils/shell_connection.py

@@ -72,7 +72,7 @@ def train(queue: Queue):
         cmd_executor = ShellCommandExecutor(subprocess_inputs, shell_output)
         try:
             # Skip initial login messages
-            result_0 = cmd_executor.execute_command(b'test')
+            result_0 = cmd_executor(b'test')
             for line in result_0:
                 lgr.debug('skipped login message line: %s', line)
             if result_0.returncode != 1:
@@ -118,11 +118,11 @@ def __init__(self,
         self.stdout = stdout
         self.end_marker, self.command_postfix = self._get_marker()
 
-    def execute_command(self,
-                        command: bytes,
-                        *,
-                        stdin: Iterable[bytes] | None = None,
-                        ) -> ShellCommandResponseGenerator:
+    def __call__(self,
+                 command: bytes,
+                 *,
+                 stdin: Iterable[bytes] | None = None,
+                 ) -> ShellCommandResponseGenerator:
         """Execute a command in the connected shell
 
         Parameters
@@ -181,7 +181,7 @@ def upload(self,
         file_size = local_path.stat().st_size
         cmd_line = f'dd bs=1 of="{remote_path.as_posix()}" count={file_size}'
         with local_path.open('rb') as local_file:
-            result = self.execute_command(
+            result = self(
                 cmd_line.encode(),
                 stdin=iter(local_file.read, b''))
             consume(result)
@@ -213,7 +213,7 @@ def download(self,
         # wire. That ensures that the end-marker is not in the downloaded data,
         # even if it is contained in the remote file.
         cmd_line = f'7z a dummy -tgzip -so "{remote_path.as_posix()}"'
-        result = self.execute_command(cmd_line.encode())
+        result = self(cmd_line.encode())
         dco = decompressobj(wbits=31)
         with local_path.open('wb') as local_file:
             for chunk in result:
@@ -247,7 +247,7 @@ def delete(self,
             'rm ' \
             + ('-f ' if force else '') \
             + ' '.join(f'"{f.as_posix()}"' for f in files)
-        result = self.execute_command(cmd_line.encode())
+        result = self(cmd_line.encode())
         consume(result)
         return result.returncode, b''.join(result.stderr_deque)
 

datalad_next/utils/tests/test_shell_connection.py

@@ -43,15 +43,15 @@ def test_basic_functionality_multi(sshserver):
 
 
 def _check_ls_result(ssh_executor, file_name: bytes):
-    results = ssh_executor.execute_command(b'ls ' + file_name)
+    results = ssh_executor(b'ls ' + file_name)
     assert b''.join(results) == file_name + b'\n'
     assert results.returncode == 0
 
 
 def test_return_code_functionality(sshserver):
     ssh_url = sshserver[0]
     with shell_connection(_get_cmdline(ssh_url)[0]) as ssh:
-        results = ssh.execute_command(b'bash -c "exit 123"')
+        results = ssh(b'bash -c "exit 123"')
         consume(results)
         assert results.returncode == 123
 
@@ -77,7 +77,7 @@ def test_stdout_forwarding_multi(sshserver):
 
 
 def _check_echo_result(ssh: ShellCommandExecutor, cmd: bytes, expected: bytes):
-    results = ssh.execute_command(cmd)
+    results = ssh(cmd)
     assert b''.join(results) == expected
     assert results.returncode == 0
 
@@ -94,7 +94,7 @@ def test_exit_if_unlimited_stdin_is_closed(sshserver):
             shell_connection(ssh_args) as ssh_executor, \
             iter_subproc([sys.executable, '-c', 'print("0123456789")']) as cat_feed:
 
-        results = ssh_executor.execute_command(b'cat >' + ssh_path, stdin=cat_feed)
+        results = ssh_executor(b'cat >' + ssh_path, stdin=cat_feed)
         ssh_executor.close()
         consume(results)
         assert results.returncode == 0
@@ -115,7 +115,7 @@ def test_continuation_after_stdin_reading(sshserver):
 
         for file_name, feed in (('dd-123', dd_feed_1), ('dd-456', dd_feed_2)):
             server_path = (ssh_path + '/' + file_name).encode()
-            results = ssh_executor.execute_command(
+            results = ssh_executor(
                 b'dd bs=1 count=10 of=' + server_path,
                 stdin=feed)
             consume(results)