FIX to display function handling null element reference, and wrong target parameter values (#1784)

* blacked

* More robust code for display, with tests

Display now includes more robust controls when checking
the input target parameters, with appropriate exception raised
(i.e. ValueError or TypeError) whether target is either
an empty string, or a not-string, not-None type, respectively.

The TypeError aligns with other similar behaviour with other Pyton
functions (e.g. str.split with integer separator).

Also, now display raises a ValueError whether the target element
is not found or not existing.

All changes are supported by tests.

* traceback lines in check_py_error & removed clones

check_py_error function now automatically includes
check of the traceback in console errors.

This way tests in basic and display have been refactored,
and lots of duplicated code removed.

* removed useless console check lines.

If check_py_errors function is running, those
console log lines are useless to check.

pyscript.core/tests/integration/test_02_display.py

@@ -11,6 +11,7 @@ import pytest
 from PIL import Image
 
 from .support import (
+    PageErrors,
     PyScriptTest,
     filter_inner_text,
     filter_page_content,
@@ -72,6 +73,67 @@ class TestDisplay(PyScriptTest):
         mydiv = self.page.locator("#mydiv")
         assert mydiv.inner_text() == "hello world"
 
+    def test_target_parameter_with_sharp(self):
+        self.pyscript_run(
+            """
+            <script type="py">
+                from pyscript import display
+                display('hello world', target="#mydiv")
+            </script>
+            <div id="mydiv"></div>
+            """
+        )
+        mydiv = self.page.locator("#mydiv")
+        assert mydiv.inner_text() == "hello world"
+
+    def test_non_existing_id_target_raises_value_error(self):
+        self.pyscript_run(
+            """
+            <script type="py">
+                from pyscript import display
+                display('hello world', target="non-existing")
+            </script>
+            """
+        )
+        error_msg = (
+            f"Invalid selector with id=non-existing. Cannot be found in the page."
+        )
+        self.check_py_errors(f"ValueError: {error_msg}")
+
+    def test_empty_string_target_raises_value_error(self):
+        self.pyscript_run(
+            """
+            <script type="py">
+                from pyscript import display
+                display('hello world', target="")
+            </script>
+            """
+        )
+        self.check_py_errors(f"ValueError: Cannot have an empty target")
+
+    def test_non_string_target_values_raise_typerror(self):
+        self.pyscript_run(
+            """
+            <script type="py">
+                from pyscript import display
+                display("hello False", target=False)
+            </script>
+            """
+        )
+        error_msg = f"target must be str or None, not bool"
+        self.check_py_errors(f"TypeError: {error_msg}")
+
+        self.pyscript_run(
+            """
+            <script type="py">
+                from pyscript import display
+                display("hello False", target=123)
+            </script>
+            """
+        )
+        error_msg = f"target must be str or None, not int"
+        self.check_py_errors(f"TypeError: {error_msg}")
+
     @skip_worker("NEXT: display(target=...) does not work")
     def test_tag_target_attribute(self):
         self.pyscript_run(