Add test for readline shell (#4447)

* fix: ReadlineShell pass stdin/out to Cmd's constructor

* test: add test for readline shell

* chore: increase required coverage

* test:

* fix: failing ci pipeline

* fix: failing ci test

.coveragerc

@@ -27,7 +27,7 @@ exclude_lines =
 skip_covered = true
 skip_empty = true
 show_missing = true
-sort = Cover
+sort = Miss
 
-# something is better than nothing :)
-fail_under = 55
+# keep improving ;)
+fail_under = 60

tests/conftest.py

@@ -183,6 +183,22 @@ def ptk_shell(xonsh_execer):
     inp.close()
 
 
+@pytest.fixture
+def readline_shell(xonsh_execer, tmpdir, mocker):
+    from xonsh.readline_shell import ReadlineShell
+
+    inp_path = tmpdir / "in"
+    inp = inp_path.open("w+")
+    out_path = tmpdir / "out"
+    out = out_path.open("w+")
+
+    shell = ReadlineShell(execer=xonsh_execer, ctx={}, stdin=inp, stdout=out)
+    mocker.patch.object(shell, "_load_remaining_input_into_queue")
+    yield shell
+    inp.close()
+    out.close()
+
+
 def pytest_configure(config):
     """Abort test run if --flake8 requested, since it would hang on parser_test.py"""
     if config.getoption("--flake8", ""):

tests/test_readline_shell.py

@@ -23,3 +23,24 @@ def test_render_completions(prefix, completion, prefix_len, readline_completion)
     assert _render_completions({completion}, prefix, prefix_len) == [
         readline_completion
     ]
+
+
+@pytest.mark.parametrize(
+    "line, exp",
+    [
+        [repr("hello"), "hello"],
+        ["2 * 3", "6"],
+    ],
+)
+def test_rl_prompt_cmdloop(line, exp, readline_shell, capsys):
+    shell = readline_shell
+    shell.use_rawinput = False
+    shell.stdin.write(f"{line}\nexit\n")  # note: terminate with '\n'
+    shell.stdin.seek(0)
+    shell.cmdloop()
+    # xonsh, doesn't write all its output to shell.stdout
+    # so capture sys.stdout
+    out, err = capsys.readouterr()
+
+    # sometimes the output has ansii color codes
+    assert exp in out.strip()

xonsh/base_shell.py

@@ -299,11 +299,18 @@ class Tee:
         return s
 
 
-class BaseShell(object):
+class BaseShell:
     """The xonsh shell."""
 
     def __init__(self, execer, ctx, **kwargs):
-        super().__init__()
+        """
+
+        Notes
+        -----
+        classes inheriting multiple base classes should call them explicitly
+        as done for ``ReadlineShell``
+        """
+
         self.execer = execer
         self.ctx = ctx
         self.completer = Completer() if kwargs.get("completer", True) else None

xonsh/readline_shell.py

@@ -320,7 +320,11 @@ class ReadlineShell(BaseShell, cmd.Cmd):
     """The readline based xonsh shell."""
 
     def __init__(self, completekey="tab", stdin=None, stdout=None, **kwargs):
-        super().__init__(completekey=completekey, stdin=stdin, stdout=stdout, **kwargs)
+        BaseShell.__init__(self, **kwargs)
+        # super() doesn't pass the stdin/stdout to Cmd's init method correctly.
+        # so calling it explicitly
+        cmd.Cmd.__init__(self, completekey=completekey, stdin=stdin, stdout=stdout)
+
         setup_readline()
         self._current_indent = ""
         self._current_prompt = ""
@@ -533,16 +537,16 @@ class ReadlineShell(BaseShell, cmd.Cmd):
         (C) Python Software Foundation, 2015.
         """
         self.preloop()
-        if self.use_rawinput and self.completekey:
-            try:
-                import readline
+        try:
+            import readline
 
+            if self.use_rawinput and self.completekey:
                 self.old_completer = readline.get_completer()
                 readline.set_completer(self.complete)
                 readline.parse_and_bind(self.completekey + ": complete")
-                have_readline = True
-            except ImportError:
-                have_readline = False
+            have_readline = True
+        except ImportError:
+            have_readline = False
         try:
             if intro is not None:
                 self.intro = intro
@@ -606,7 +610,7 @@ class ReadlineShell(BaseShell, cmd.Cmd):
             try:
                 self._cmdloop(intro=intro)
             except (KeyboardInterrupt, SystemExit):
-                print()  # Gives a newline
+                print(file=self.stdout)  # Gives a newline
                 fix_readline_state_after_ctrl_c()
                 self.reset_buffer()
                 intro = None