From 398d62097d84fb0871809a7e555cb4b89bb5f2ea Mon Sep 17 00:00:00 2001
From: lola <keepthechange2021@gmail.com>
Date: Tue, 21 Oct 2025 11:08:49 -0700
Subject: [PATCH 1/2] add tests for multiple assignments and unpacking

---
 tests/syntax/test_assignments.py | 66 ++++++++++++++++++++++++++++++++
 tests/syntax/test_parser.py      | 14 +++++++
 2 files changed, 80 insertions(+)
 create mode 100644 tests/syntax/test_assignments.py

diff --git a/tests/syntax/test_assignments.py b/tests/syntax/test_assignments.py
new file mode 100644
index 000000000..fe7812d65
--- /dev/null
+++ b/tests/syntax/test_assignments.py
@@ -0,0 +1,66 @@
+# Minimal semantics tests for multiple assignment and LHS unpacking.
+
+import pytest
+
+from tests.utils import compileScenic, sampleEgoActions
+
+
+def test_multiple_assignment_swap():
+    scenario = compileScenic(
+        """
+        behavior Foo():
+            a = 1
+            b = 2
+            a, b = b, a
+            take a
+            take b
+        ego = new Object with behavior Foo
+        """
+    )
+    actions = sampleEgoActions(scenario, maxSteps=2)
+    assert actions == [2, 1]
+
+
+def test_lhs_tuple_unpack():
+    scenario = compileScenic(
+        """
+        behavior Foo():
+            x, y = (3, 4)
+            take x
+            take y
+        ego = new Object with behavior Foo
+        """
+    )
+    assert sampleEgoActions(scenario, maxSteps=2) == [3, 4]
+
+
+def test_unpack_from_distribution_pair():
+    scenario = compileScenic(
+        """
+        behavior Foo():
+            pair = Uniform((0, 1), (1, 0))
+            x, y = pair
+            take x
+            take y
+        ego = new Object with behavior Foo
+        """
+    )
+    outs = [tuple(sampleEgoActions(scenario, maxSteps=2)) for _ in range(60)]
+    assert {(0, 1), (1, 0)} <= set(outs)
+
+
+@pytest.mark.parametrize(
+    "rhs",
+    ["(1, 2, 3)", "(1,)"],  # too many; not enough
+)
+def test_unpack_arity_mismatch_exec_raises(rhs):
+    scenario = compileScenic(
+        f"""
+        behavior Foo():
+            x, y = {rhs}
+            take x
+        ego = new Object with behavior Foo
+    """
+    )
+    with pytest.raises(ValueError):
+        sampleEgoActions(scenario, maxSteps=1)
diff --git a/tests/syntax/test_parser.py b/tests/syntax/test_parser.py
index 8267466c6..e073cb655 100644
--- a/tests/syntax/test_parser.py
+++ b/tests/syntax/test_parser.py
@@ -168,6 +168,20 @@ def test_workspace_assign(self):
                 assert False
 
 
+class TestAssign:
+    def test_tuple_lhs_parses(self):
+        mod = parse_string_helper("a, b = 1, 2")
+        stmt = mod.body[0]
+        match stmt:
+            case Assign(
+                targets=[Tuple([Name("a"), Name("b")])],
+                value=Tuple([Constant(1), Constant(2)]),
+            ):
+                assert True
+            case _:
+                assert False
+
+
 class TestInitialScenario:
     def test_initial_scenario(self):
         mod = parse_string_helper("initial scenario")

From b4052bf1a1af21e964524a225de98ad81a6e4384 Mon Sep 17 00:00:00 2001
From: lola <keepthechange2021@gmail.com>
Date: Mon, 17 Nov 2025 11:30:12 -0800
Subject: [PATCH 2/2] simplify tests, just use top level code

---
 tests/syntax/test_assignments.py | 66 +++++++++++++-------------------
 1 file changed, 27 insertions(+), 39 deletions(-)

diff --git a/tests/syntax/test_assignments.py b/tests/syntax/test_assignments.py
index fe7812d65..99b36abbc 100644
--- a/tests/syntax/test_assignments.py
+++ b/tests/syntax/test_assignments.py
@@ -2,51 +2,42 @@
 
 import pytest
 
-from tests.utils import compileScenic, sampleEgoActions
+from tests.utils import sampleParamPFrom
 
 
 def test_multiple_assignment_swap():
-    scenario = compileScenic(
+    p = sampleParamPFrom(
         """
-        behavior Foo():
-            a = 1
-            b = 2
-            a, b = b, a
-            take a
-            take b
-        ego = new Object with behavior Foo
+        a = 1
+        b = 2
+        a, b = b, a
+        param p = (a, b)
         """
     )
-    actions = sampleEgoActions(scenario, maxSteps=2)
-    assert actions == [2, 1]
+    assert p == (2, 1)
 
 
 def test_lhs_tuple_unpack():
-    scenario = compileScenic(
+    p = sampleParamPFrom(
         """
-        behavior Foo():
-            x, y = (3, 4)
-            take x
-            take y
-        ego = new Object with behavior Foo
+        x, y = (3, 4)
+        param p = (x, y)
         """
     )
-    assert sampleEgoActions(scenario, maxSteps=2) == [3, 4]
+    assert p == (3, 4)
 
 
 def test_unpack_from_distribution_pair():
-    scenario = compileScenic(
-        """
-        behavior Foo():
-            pair = Uniform((0, 1), (1, 0))
-            x, y = pair
-            take x
-            take y
-        ego = new Object with behavior Foo
-        """
-    )
-    outs = [tuple(sampleEgoActions(scenario, maxSteps=2)) for _ in range(60)]
-    assert {(0, 1), (1, 0)} <= set(outs)
+    code = """
+        pair = (Uniform(0, 1), Uniform(0, 1))
+        x, y = pair
+        param p = (x, y)
+    """
+    outs = [sampleParamPFrom(code) for _ in range(20)]
+    assert len(set(outs)) > 1
+    for x, y in outs:
+        assert 0 <= x <= 1
+        assert 0 <= y <= 1
 
 
 @pytest.mark.parametrize(
@@ -54,13 +45,10 @@ def test_unpack_from_distribution_pair():
     ["(1, 2, 3)", "(1,)"],  # too many; not enough
 )
 def test_unpack_arity_mismatch_exec_raises(rhs):
-    scenario = compileScenic(
-        f"""
-        behavior Foo():
-            x, y = {rhs}
-            take x
-        ego = new Object with behavior Foo
-    """
-    )
     with pytest.raises(ValueError):
-        sampleEgoActions(scenario, maxSteps=1)
+        sampleParamPFrom(
+            f"""
+            x, y = {rhs}
+            param p = x
+            """
+        )