This PR implements a method in the MathicsSession class that uses the…

… Evaluation.evaluate method. This allows to handle exceptions and special symbols like % or Line references. This method is used in certain pytests.

mathics/session.py

@@ -86,13 +86,21 @@ def reset(self, add_builtin=True, catch_interrupt=False):
         self.last_result = None
 
     def evaluate(self, str_expression, timeout=None, form=None):
+        """Parse str_expression and evaluate using the `evaluate` method of the Expression"""
         self.evaluation.out.clear()
         expr = parse(self.definitions, MathicsSingleLineFeeder(str_expression))
         if form is None:
             form = self.form
         self.last_result = expr.evaluate(self.evaluation)
         return self.last_result
 
+    def evaluate_as_in_cli(self, str_expression, timeout=None, form=None):
+        """This method parse and evaluate the expression using the session.evaluation.evaluate method"""
+        query = self.evaluation.parse(str_expression)
+        res = self.evaluation.evaluate(query)
+        self.evaluation.stopped = False
+        return res
+
     def format_result(self, str_expression=None, timeout=None, form=None):
         if str_expression:
             self.evaluate(str_expression, timeout=None, form=None)

test/builtin/test_attributes.py

@@ -4,7 +4,7 @@
 """
 
 import os
-from test.helper import check_evaluation, session
+from test.helper import check_evaluation, check_evaluation_as_in_cli, session
 
 import pytest
 
@@ -282,28 +282,4 @@ def test_private_doctests_attributes_with_exceptions(
     str_expr, msgs, str_expected, fail_msg
 ):
     """These tests check the behavior of $RecursionLimit and $IterationLimit"""
-
-    # Here we do not use the session object to check the messages
-    # produced by the exceptions. If $RecursionLimit / $IterationLimit
-    # are reached during the evaluation using a MathicsSession object,
-    # an exception is raised. On the other hand, using the `Evaluation.evaluate`
-    # method, the exception is handled.
-    #
-    # TODO: Maybe it makes sense to clone this exception handling in
-    # the check_evaluation function.
-    #
-    def eval_expr(expr_str):
-        query = session.evaluation.parse(expr_str)
-        res = session.evaluation.evaluate(query)
-        session.evaluation.stopped = False
-        return res
-
-    res = eval_expr(str_expr)
-    if msgs is None:
-        assert len(res.out) == 0
-    else:
-        assert len(res.out) == len(msgs)
-        for li1, li2 in zip(res.out, msgs):
-            assert li1.text == li2
-
-    assert res.result == str_expected
+    check_evaluation_as_in_cli(str_expr, str_expected, fail_msg, msgs)

test/builtin/test_evalution.py

@@ -4,7 +4,7 @@
 """
 
 
-from test.helper import check_evaluation, session
+from test.helper import check_evaluation_as_in_cli, session
 
 import pytest
 
@@ -66,28 +66,4 @@
 )
 def test_private_doctests_evaluation(str_expr, msgs, str_expected, fail_msg):
     """These tests check the behavior of $RecursionLimit and $IterationLimit"""
-
-    # Here we do not use the session object to check the messages
-    # produced by the exceptions. If $RecursionLimit / $IterationLimit
-    # are reached during the evaluation using a MathicsSession object,
-    # an exception is raised. On the other hand, using the `Evaluation.evaluate`
-    # method, the exception is handled.
-    #
-    # TODO: Maybe it makes sense to clone this exception handling in
-    # the check_evaluation function.
-    #
-    def eval_expr(expr_str):
-        query = session.evaluation.parse(expr_str)
-        res = session.evaluation.evaluate(query)
-        session.evaluation.stopped = False
-        return res
-
-    res = eval_expr(str_expr)
-    if msgs is None:
-        assert len(res.out) == 0
-    else:
-        assert len(res.out) == len(msgs)
-        for li1, li2 in zip(res.out, msgs):
-            assert li1.text == li2
-
-    assert res.result == str_expected
+    check_evaluation_as_in_cli(str_expr, str_expected, fail_msg, msgs)

test/builtin/test_functional.py

@@ -5,7 +5,7 @@
 
 import sys
 import time
-from test.helper import check_evaluation, evaluate, session
+from test.helper import check_evaluation, check_evaluation_as_in_cli, evaluate, session
 
 import pytest
 
@@ -95,22 +95,7 @@
 )
 def test_private_doctests_apply_fns_to_lists(str_expr, msgs, str_expected, fail_msg):
     """functional.apply_fns_to_lists"""
-
-    def eval_expr(expr_str):
-        query = session.evaluation.parse(expr_str)
-        res = session.evaluation.evaluate(query)
-        session.evaluation.stopped = False
-        return res
-
-    res = eval_expr(str_expr)
-    if msgs is None:
-        assert len(res.out) == 0
-    else:
-        assert len(res.out) == len(msgs)
-        for li1, li2 in zip(res.out, msgs):
-            assert li1.text == li2
-
-    assert res.result == str_expected
+    check_evaluation_as_in_cli(str_expr, str_expected, fail_msg, msgs)
 
 
 @pytest.mark.parametrize(

test/builtin/test_messages.py

@@ -4,7 +4,7 @@
 """
 
 
-from test.helper import check_evaluation, session
+from test.helper import check_evaluation_as_in_cli, session
 
 import pytest
 
@@ -136,19 +136,4 @@
 )
 def test_private_doctests_messages(str_expr, msgs, str_expected, fail_msg):
     """These tests check the behavior the module messages"""
-
-    def eval_expr(expr_str):
-        query = session.evaluation.parse(expr_str)
-        res = session.evaluation.evaluate(query)
-        session.evaluation.stopped = False
-        return res
-
-    res = eval_expr(str_expr)
-    if msgs is None:
-        assert len(res.out) == 0
-    else:
-        assert len(res.out) == len(msgs)
-        for li1, li2 in zip(res.out, msgs):
-            assert li1.text == li2
-
-    assert res.result == str_expected
+    check_evaluation_as_in_cli(str_expr, str_expected, fail_msg, msgs)

test/builtin/test_procedural.py

@@ -3,7 +3,7 @@
 Unit tests from mathics.builtin.procedural.
 """
 
-from test.helper import check_evaluation, session
+from test.helper import check_evaluation, check_evaluation_as_in_cli, session
 
 import pytest
 
@@ -111,6 +111,19 @@ def test_private_doctests_procedural(str_expr, msgs, str_expected, fail_msg):
 
 def test_history_compound_expression():
     """Test the effect in the history from the evaluation of a CompoundExpression"""
+    check_evaluation_as_in_cli("Clear[x];Clear[y]")
+    check_evaluation_as_in_cli("CompoundExpression[x, y, Null]")
+    check_evaluation_as_in_cli("ToString[%]", "y")
+    check_evaluation_as_in_cli(
+        "CompoundExpression[CompoundExpression[y, x, Null], Null]"
+    )
+    check_evaluation_as_in_cli("ToString[%]", "x")
+    check_evaluation_as_in_cli("CompoundExpression[x, y, Null, Null]")
+    check_evaluation_as_in_cli("ToString[%]", "y")
+    check_evaluation_as_in_cli("CompoundExpression[]")
+    check_evaluation_as_in_cli("ToString[%]", "Null")
+    check_evaluation_as_in_cli("Clear[x];Clear[y];")
+    return
 
     def eval_expr(expr_str):
         query = session.evaluation.parse(expr_str)
@@ -119,7 +132,7 @@ def eval_expr(expr_str):
     eval_expr("Clear[x];Clear[y]")
     eval_expr("CompoundExpression[x, y, Null]")
     assert eval_expr("ToString[%]").result == "y"
-    eval_expr("CompoundExpression[CompoundExpression[y, x, Null], Null]")
+    eval_expr("CompoundExpression[CompoundExpression[y, x, Null], Null])")
     assert eval_expr("ToString[%]").result == "x"
     eval_expr("CompoundExpression[x, y, Null, Null]")
     assert eval_expr("ToString[%]").result == "y"

test/helper.py

@@ -27,7 +27,7 @@ def evaluate(str_expr: str):
 
 
 def check_evaluation(
-    str_expr: str,
+    str_expr: Optional[str],
     str_expected: Optional[str] = None,
     failure_message: str = "",
     hold_expected: bool = False,
@@ -122,3 +122,30 @@ def check_evaluation(
                 print(" and ")
                 print(f"expected=<<{msg}>>")
                 assert False, " do not match."
+
+
+def check_evaluation_as_in_cli(
+    str_expr: Optional[str] = None,
+    str_expected: Optional[str] = None,
+    failure_message: str = "",
+    expected_messages: Optional[tuple] = None,
+):
+    """
+    Use this method when special Symbols like Return, %, %%,
+    $IterationLimit, $RecursionLimit, etc. are used in the tests.
+    """
+    if str_expr is None:
+        reset_session()
+        return
+
+    res = session.evaluate_as_in_cli(str_expr)
+    if expected_messages is None:
+        assert len(res.out) == 0
+    else:
+        assert len(res.out) == len(expected_messages)
+        for li1, li2 in zip(res.out, expected_messages):
+            assert li1.text == li2
+
+    if failure_message:
+        assert res.result == str_expected, failure_message
+    assert res.result == str_expected