Fix #1834 - Throw an error if more than a terminal exists (#1837)

pyscript.core/src/plugins/py-terminal.js

@@ -1,27 +1,35 @@
 // PyScript py-terminal plugin
 import { TYPES, hooks } from "../core.js";
+import { notify } from "./error.js";
 
 const SELECTOR = [...TYPES.keys()]
     .map((type) => `script[type="${type}"][terminal],${type}-script[terminal]`)
     .join(",");
 
+// show the error on main and
+// stops the module from keep executing
+const notifyAndThrow = (message) => {
+    notify(message);
+    throw new Error(message);
+};
+
 const pyTerminal = async () => {
     const terminals = document.querySelectorAll(SELECTOR);
 
     // no results will look further for runtime nodes
     if (!terminals.length) return;
 
-    // we currently support only one terminal as in "classic"
-    if (terminals.length > 1)
-        console.warn("Unable to satisfy multiple terminals");
-
     // if we arrived this far, let's drop the MutationObserver
+    // as we only support one terminal per page (right now).
     mo.disconnect();
 
+    // we currently support only one terminal as in "classic"
+    if (terminals.length > 1) notifyAndThrow("You can use at most 1 terminal.");
+
     const [element] = terminals;
     // hopefully to be removed in the near future!
     if (element.matches('script[type="mpy"],mpy-script'))
-        throw new Error("Unsupported terminal");
+        notifyAndThrow("Unsupported terminal.");
 
     // import styles lazily
     document.head.append(

pyscript.core/tests/integration/support.py

@@ -118,6 +118,20 @@ def only_main(fn):
     return decorated
 
 
+def only_worker(fn):
+    """
+    Decorator to mark a test which make sense only in the worker thread
+    """
+
+    @functools.wraps(fn)
+    def decorated(self, *args):
+        if self.execution_thread != "worker":
+            return
+        return fn(self, *args)
+
+    return decorated
+
+
 def filter_inner_text(text, exclude=None):
     return "\n".join(filter_page_content(text.splitlines(), exclude=exclude))
 

pyscript.core/tests/integration/test_01_basic.py

@@ -80,7 +80,7 @@ class TestBasic(PyScriptTest):
                 '"Cross-Origin-Opener-Policy":"same-origin"}. '
                 "The problem may be that one or both of these are missing."
             )
-            alert_banner = self.page.wait_for_selector(".alert-banner")
+            alert_banner = self.page.wait_for_selector(".py-error")
             assert expected_alert_banner_msg in alert_banner.inner_text()
 
     def test_print(self):

pyscript.core/tests/integration/test_py_terminal.py

@@ -1,12 +1,45 @@
 import time
 
+import pytest
 from playwright.sync_api import expect
 
-from .support import PyScriptTest, skip_worker
+from .support import PageErrors, PyScriptTest, only_worker, skip_worker
 
 
 class TestPyTerminal(PyScriptTest):
-    @skip_worker("FIXME: the auto worker dance removes terminal")
+    def test_multiple_terminals(self):
+        """
+        Multiple terminals are not currently supported
+        """
+        self.pyscript_run(
+            """
+            <script type="py" terminal></script>
+            <script type="py" terminal></script>
+            """,
+            wait_for_pyscript=False,
+            check_js_errors=False,
+        )
+        assert self.assert_banner_message("You can use at most 1 terminal")
+
+        with pytest.raises(PageErrors, match="You can use at most 1 terminal"):
+            self.check_js_errors()
+
+    @only_worker
+    def test_py_terminal_input(self):
+        """
+        Only worker py-terminal accepts an input
+        """
+        self.pyscript_run(
+            """
+            <script type="py" terminal></script>
+            """,
+            wait_for_pyscript=False,
+        )
+        self.page.get_by_text(">>> ", exact=True).wait_for()
+        self.page.keyboard.type("'the answer is ' + str(6 * 7)")
+        self.page.keyboard.press("Enter")
+        self.page.get_by_text("the answer is 42").wait_for()
+
     def test_py_terminal(self):
         """
         1. <py-terminal> should redirect stdout and stderr to the DOM
@@ -21,8 +54,10 @@ class TestPyTerminal(PyScriptTest):
                 print('this goes to stderr', file=sys.stderr)
                 print('this goes to stdout')
             </script>
-            """
+            """,
+            wait_for_pyscript=False,
         )
+        self.page.get_by_text("hello world").wait_for()
         term = self.page.locator("py-terminal")
         term_lines = term.inner_text().splitlines()
         assert term_lines[0:3] == [
@@ -31,7 +66,9 @@ class TestPyTerminal(PyScriptTest):
             "this goes to stdout",
         ]
 
-    @skip_worker("FIXME: the auto worker dance removes terminal")
+    @skip_worker(
+        "Workers don't have events + two different workers don't share the same I/O"
+    )
     def test_button_action(self):
         self.pyscript_run(
             """
@@ -50,7 +87,6 @@ class TestPyTerminal(PyScriptTest):
         last_line.wait_for()
         assert term.inner_text().rstrip() == "hello world"
 
-    @skip_worker("FIXME: the auto worker dance removes terminal")
     def test_xterm_function(self):
         """Test a few basic behaviors of the xtermjs terminal.
 
@@ -69,7 +105,8 @@ class TestPyTerminal(PyScriptTest):
                 print("\x1b[3mItalic\x1b[23m")
                 print("done")
             </script>
-            """
+            """,
+            wait_for_pyscript=False,
         )
 
         # Wait for "done" to actually appear in the xterm; may be delayed,