Add unit test for async and await statement

Author: jaepil

tests/expressions/test_interpreter_async.py

@@ -0,0 +1,152 @@
+#
+# Monic Framework
+#
+# Copyright (c) 2024-2025 Cognica, Inc.
+#
+
+import pytest
+
+from monic.expressions import ExpressionsParser, ExpressionsInterpreter
+
+
+def test_awaitable_value():
+    """Test that AwaitableValue.__await__ works correctly."""
+    # Create a simple async function that returns a value
+    code = """
+async def test_func():
+    return 42
+
+await test_func()
+"""
+
+    parser = ExpressionsParser()
+    interpreter = ExpressionsInterpreter()
+
+    # Execute the code
+    result = interpreter.execute(parser.parse(code))
+
+    # The result should be 42
+    assert result == 42
+
+
+def test_awaitable_value_with_error():
+    """Test that AwaitableValue.__await__ handles errors correctly."""
+    # Create an async function that raises an error
+    code = """
+async def test_func():
+    raise ValueError("test error")
+
+await test_func()
+"""
+
+    parser = ExpressionsParser()
+    interpreter = ExpressionsInterpreter()
+
+    # The execution should raise ValueError
+    with pytest.raises(ValueError, match="test error"):
+        interpreter.execute(parser.parse(code))
+
+
+def test_awaitable_value_return():
+    """Test that AwaitableValue.__await__ returns the correct value."""
+    # Create an async function that returns a value through StopIteration
+    code = """
+async def test_func():
+    # This will make __await__ return the value through StopIteration
+    return await test_func() if False else 42
+
+await test_func()
+"""
+
+    parser = ExpressionsParser()
+    interpreter = ExpressionsInterpreter()
+
+    # Execute the code
+    result = interpreter.execute(parser.parse(code))
+
+    # The result should be 42
+    assert result == 42
+
+
+def test_awaitable_value_direct_return():
+    """Test that AwaitableValue.__await__ directly returns its value."""
+    # Create an async function that returns a value directly
+    code = """
+async def test_func():
+    # This will make __await__ directly return its value
+    return 42
+
+# Call the function multiple times to ensure the value is returned correctly
+result1 = await test_func()
+result2 = await test_func()
+result1 + result2  # This should be 84
+"""
+
+    parser = ExpressionsParser()
+    interpreter = ExpressionsInterpreter()
+
+    # Execute the code
+    result = interpreter.execute(parser.parse(code))
+
+    # The result should be 84 (42 + 42)
+    assert result == 84
+
+
+def test_awaitable_value_direct():
+    """
+    Test that AwaitableValue.__await__ directly returns its value by creating
+    an awaitable value directly.
+    """
+    code = """
+async def create_awaitable():
+    # This will create an awaitable value that will be awaited directly
+    return 42
+
+# Get the awaitable value
+awaitable = create_awaitable()
+# Await it directly
+result1 = await awaitable
+# Await it again to ensure it works multiple times
+result2 = await awaitable
+result1 + result2  # This should be 84
+"""
+
+    parser = ExpressionsParser()
+    interpreter = ExpressionsInterpreter()
+
+    # Execute the code
+    result = interpreter.execute(parser.parse(code))
+
+    # The result should be 84 (42 + 42)
+    assert result == 84
+
+
+def test_awaitable_value_complex():
+    """
+    Test that AwaitableValue.__await__ returns its value in a more complex
+    scenario.
+    """
+    code = """
+async def nested_awaitable():
+    # This will create a chain of awaitable values
+    async def inner():
+        return 42
+
+    # First await will yield the value
+    value = await inner()
+    # Second await will return the value
+    return await inner()
+
+# Execute the nested awaitable
+result = await nested_awaitable()
+result  # This should be 42
+"""
+
+    parser = ExpressionsParser()
+    interpreter = ExpressionsInterpreter()
+
+    # Execute the code
+    result = interpreter.execute(parser.parse(code))
+
+    # The result should be 42
+    assert result == 42