add test

Author: braised-babbage

source/openpulse/openpulse/parser.py

@@ -51,10 +51,12 @@
 from ._antlr.openpulseParser import openpulseParser
 from ._antlr.openpulseParserVisitor import openpulseParserVisitor
 
+
 class OpenPulseParsingError(Exception):
     """An error raised by the AST visitor during the AST-generation phase.  This is raised in cases where the
     given program could not be correctly parsed."""
 
+
 def parse(input_: str, permissive: bool = False) -> ast.Program:
     """
     Parse a complete OpenPulse program from a string.
@@ -71,7 +73,9 @@ def parse(input_: str, permissive: bool = False) -> ast.Program:
     return qasm3_ast
 
 
-def parse_openpulse(input_: str, in_defcal: bool, permissive: bool = True) -> openpulse_ast.CalibrationBlock:
+def parse_openpulse(
+    input_: str, in_defcal: bool, permissive: bool = True
+) -> openpulse_ast.CalibrationBlock:
     lexer = openpulseLexer(InputStream(input_))
     stream = CommonTokenStream(lexer)
     parser = openpulseParser(stream)

source/openpulse/tests/test_openpulse_parser.py

@@ -38,7 +38,7 @@
     UnaryOperator,
     WaveformType,
 )
-from openpulse.parser import parse
+from openpulse.parser import parse, OpenPulseParsingError
 from openqasm3.visitor import QASMVisitor
 
 
@@ -368,6 +368,29 @@ def test_switch_in_cal_block():
     assert _remove_spans(program) == expected
 
 
+def test_permissive_parsing(capsys):
+    p = """
+    cal {
+      int;
+    }
+    """
+
+    with pytest.raises(AttributeError, match=r"'NoneType' object has no attribute 'line'"):
+        # In this case, we do get an exception, but this is somewhat incidental --
+        # the antlr parser gives us a `None` value where we expect a `Statement`
+        parse(p, permissive=True)
+    # The actual ANTLR failure is reported via stderr
+    captured = capsys.readouterr()
+    assert captured.err.strip() == "line 2:9 no viable alternative at input 'int;'"
+
+    with pytest.raises(OpenPulseParsingError):
+        # This is stricter -- we fail as soon as ANTLR sees a problem
+        parse(p)
+    captured = capsys.readouterr()
+    # The actual ANTLR failure is reported via stderr
+    assert captured.err.strip() == "line 2:9 no viable alternative at input 'int;'"
+
+
 @pytest.mark.parametrize(
     "p",
     [